No. 22 - Gibraltar Ornithological & Natural History Society

GUNS,
HERBS
& BEASTS
Leslie Linares, Keith Bensusan, Charles Perez & Alex Menez
Windmill Hill Flats is a large, relatively
flat area located at the southern end of the
Rock. It has been an MOD military training
area for many years and is also an MOD
conservation area. This, together with its
recent listing under the EU Habitats Directive,
affords the flora and fauna of the area protection.
However, the surface of the Flats
has suffered much disturbance over time.
Buildings, gun emplacements, firing ranges,
aerial pylons and other structures have been
constructed there, with many subsequently
being removed or left derelict. All have left
their mark.
Despite this disturbance and the fact that
the soil covering most of the Flats is thin and of
poor quality, the flora and fauna of the area
thrive to make this one of the prime sites for
wildlife in Gibraltar. Windmill Hill Flats contain
an extraordinary assemblage of plant
species, which at the last count reached a
total of 283. Many of these are either found
here and nowhere else on the Rock or are
very rare elsewhere. Among those unique
to the Flats are the Southern Autumn Crocus
Crocus serotinus subsp. salzmannii, Bastard
Toadflax Thesium humile, Saw-tooth Plantain
Plantago serraria, Wild Clary Salvia verbenaca,
Dagger Flower Mantisalca salmantica,
Pygmy Cudweed Filago pygmaea,
Ovate Goat Grass Aegilops geniculata,
Italian Sainfoin Hedysarum coronarium and
Winged Pea Lotus tetragonolobus.
The species that are found on the Flats
don’t just have to survive the poor soil. The
area is exposed to the full force of both
Easterly and Westerly winds and strong
Easterly winds are also salt-laden. Large
sections of the Flats are completely lacking
in tree or shrub cover and are fully
exposed to the sun. Only the most hardy
species are able to survive this harsh environment.
Despite the harsh environment of
the Flats however, a couple of small stands
of Bee Orchids Ophrys apifera have been
established there for some time. These are
extremely rare locally and are a protected
species.
Other less exposed areas, generally
forming the perimeter from south-east to
south-west, have a low, dense cover of
Crocus serotinus subsp salzmannii
Summer - Autumn 2012 - No. 22
shrubs, mainly Olive Olea europaea, Lentisc
Pistacia lentiscus, Spiny Broom Calicotome
villosa, Spiny Ivy Smilax aspera, Flax-leaved
Broom Genista linifolia and Joint-pine
Ephedra fragilis. In these areas, less hardy
species are afforded some degree of protection
by the shrub cover, but their survival
is threatened by the increasing density of
the vegetation. There are two areas where
this is particularly so. One is the slope
immediately south of the Signal Station,
and to a lesser extent the northern part of
the rocky outcrop upon which the Signal
Station stands. Here are found the extremely
rare Thesium and the rare Crocus. Both are
protected and endangered species locally.
The other area lies along the eastern edge
of the Flats, between the small range and the
old magazine building north of Buffadero
Battery. Here there is an excellent stand of
Warty Spurge Euphorbia squamigera that
is threatened by the spread of other shrubs.
The firing range is also home to a large
number of species. This is because the soil
used on the range was imported and with it
came a large number of seeds. These have
germinated and managed to survive despite
the environment and, up to a point, as a
result of the regular strimming of vegetation.
Among them are the Early Storksbill Erodium
primulaceum, Narbonne Star of Bethlehem
Ornithogalum narbonense, Corn Camomile
Anthemis arvensis, Subterranean Clover
... continued on P. 16

GIBRALTAR NATURE NEWS
2
Guns, Herbs and Beasts 1 & 16
Editorial 2
Birding scene 3
Name changes 4 & 5
Local wildlife websites and blogs 6
Windmill Hill collaboration 6
Upper Rock Team continues to
work for Gibraltar’s flora 7
Photo stacking 8 & 9
Fishing dispute causes GONHS
serious concern 10
Rhian leading research on ants 10
Captive breeding programme 11
Tidal power in Guernsey 12 & 13
Natural history and art -
What about graffiti? 14 & 15
PHOTO CREDITS
Leslie Linares
Charles Perez
Clive Finlayson
Alex Menez
Nicholas Ferrary
Andrew Casebow
Gilbert Gonzalez
Keith Bensusan
Paul Acolina
CONTRIBUTORS
Keith Bensusan
Charles Perez
Leslie Linares
Alex Menez
Vincent Robba
Andrew Casebow
Published by the
Gibraltar Ornithological & Natural History Society
Natural History Field Centre, Jews’ Gate,
Upper Rock Nature Reserve
P.O.Box 843, Gibraltar
Tel. 200 72639 - Fax. 200 74022
e-mail: editors@gonhs.org
http//:www.gonhs.org
Editorial team:
Leslie Linares,
Charles Perez,
Keith Bensusan,
Alex Menez
Designed and printed by
Roca Graphics Ltd. Gibraltar
21 Tuckeys Lane, Gibraltar.
Tel. +350 200 57955
Editorial
Where do we go
from here?
As our readers will be aware, Dr John
Cortes is no longer General Secretary of this
organisation, having taken on the responsibility
of Government as Gibraltar’s new Minister
for Health and the Environment. Dr Cortes’
contribution to GONHS cannot be overstated.
An intelligent and passionate man with the
strongest commitment towards the conservation
of Gibraltar’s Wildlife, John worked ceaselessly
on the organisation’s behalf, often working
long hours into the night and labouring
with important issues during weekends. In this
sense, leading this organisation could be said
to have prepared Dr Cortes for his ministerial
role.
GONHS wishes Dr Cortes every success
as Minister for the Environment and is confident
that his scientific background, wealth of
knowledge, experience, and tireless work ethic
will help to thrust Gibraltar into the forefront of
Wildlife Conservation, an example for small
territories elsewhere. We know that if anyone
can achieve this, Dr Cortes can. As those
of you who count John among your personal
friends will agree, nobody deserves such a
resounding election victory more than he does.
Dr Cortes’ exit does of course leave a large
void in GONHS, from its running to the preparation
of articles for this magazine. To emulate
Dr Cortes in his past endeavour would require
a herculean approach from any one individual,
but luckily GONHS has a strong, experienced,
expert and committed Council, twelve-person
strong and each willing to do his or her bit
to ensure that the organisation remains afloat
and indeed continues to progress its objectives
and ideals.
This Council was elected on the 25th
January, with Charlie Perez selected as the
new General Secretary. Those familiar with
GONHS will know that Charlie’s expertise of
and dedication to Gibraltar’s varied wildlife
and its conservation will aid him greatly in a
role that, as Council is already experiencing,
he is undertaking admirably. As a colleague
and personal friend of Charlie’s, I cannot
emphasise enough the importance of Charlie’s
personal qualities to GONHS. I personally
look forward to working with him in my new
capacity as the head of the Strait of Gibraltar
Bird Observatory, as I know other section
heads do too. An article in the next issue of
‘Gibraltar Nature News’ will summarise your
Council members, their attributes and responsibilities.
Another change brought about by Dr
Cortes’ departure has been the recruitment of
Dr Alex Menez as co-editor of this magazine,
as well as his appointment to Council as the
new head of the Invertebrate Section, following
my taking over the Strait of Gibraltar Bird
Observatory from Charlie Perez. Alex has a
strong background as a scientist, especially as
an ecologist, evolutionist and expert on Land
Molluscs. He brings fresh and new ideas to
the table and we very much look forward to his
input to Nature News.
The editorial team of Gibraltar Nature
News had long been discussing the possibility
of new ideas and features in our magazine.
We have now decided how to bring these
about. Future issues will include a Letters
section and a Children’s section, as well as
greater emphasis on authored articles. It will
also, on the basis of the success of the GONHS
Facebook page, be selecting some of the best
questions posed on this page by members and
publishing these together with their answers.
A ‘Notes & News’ item in this issue highlights
some of these proposed changes and what
they require from you, our dear and valued
reader. I have no problem conceding that most
of these initiatives are Alex’s: change, when
carefully considered, is inevitably a good thing
that leads to revitalisation and innovation.
A question our organisation must ask
itself is “where do we go from here?” as the
heading of this editorial states. Although seen
primarily as a conservation organisation by
many, we should not forget that the Society
was, from the onset, one that aimed to study
Gibraltar’s wildlife and foster scientific study
of ecological issues in Gibraltar. This has not
changed and GONHS has always been active
in research. However this has, of necessity,
taken a backseat to more pressing issues such
as the infamous Funicular or Dolphinarium,
which frankly, a Government that is committed
to environmental well-being should have
discouraged from the beginning. Thus, people
have often heard about GONHS via its campaigns
rather than its scientific work.
This issue of Nature News and the next
carry reports of strong and cutting-edge scientific
work carried out by members of several
of the sections. In particular, praise must be
heaped upon the members of the Cave Science
Unit of the Caves and Cliffs section. The unit,
comprised entirely of volunteers, is a full member
of one of the strongest teams in the field
of cave science. The Cave Science Unit was
putting Gibraltar firmly on the map behind
the scenes whilst GONHS was busy fighting
this battle and that. If only we had had more
time to broadcast these achievements instead
of having to campaign against proposed
threats to our natural environment…but we do
not regret it, and we are left to wonder what
Gibraltar’s landscape and wildlife would be
like had it not been for GONHS.
We should, as we always have, be willing
to engage Government to try and resolve
matters amicably. Acrimony only achieves
entrenchment of opponents in their respective
positions, whereas compromise, best achieved
via dialogue, often leads to solutions that are
mutually acceptable to both parties. However,
it is important to point out that if GONHS and
Government come to loggerheads over any
issues, then GONHS shall defend its views
and objectives as passionately, vociferously
and resolutely as it always has. We hope that
the strong, friendly and frank relationship that
this organisation maintains with Minister Cortes
(who is still a GONHS member) will facilitate
mutually acceptable resolutions or, if we cannot
find common ground, that we furnish each
other with the respect and maturity that we
should expect from those committed to rational
thought and intelligent debate.
We are hopeful that a renewed impetus
from the Government to adequately protect
Gibraltar’s wildlife, together with the changes
described above, will allow GONHS to continue
to develop its aims as an organisation
that protects Gibraltar’s natural environment
and helps to foster and carry out research on
our wonderful wildlife.
Keith Bensusan, Co-editor

BIRDING SCENE: VAGRANT BIRDS IN GIBRALTAR
Gibraltar has had its fair share of vagrants.
Although a small piece of land by any standards,
6 km 2, it has the following attributes:
• It is located between two continents and
two seas
• It lies along one of the busiest maritime
routes in the world,
• It is at the crossroads of a major migr
tory route for seabirds, raptors and
passerines
It is therefore only a question of time and
patience before an observer encounters a rare
bird.
At the beginning of this year, a Yellowbrowed
Warbler Phylloscopus inornatus was
discovered wintering in the Mount Garden.
An Asiatic species that is recorded annually
in western Europe, it was located by its
characteristic call and spent several months at
home in one particular tree, the Asian fig species
Ficus microcarpa. The species has been
recorded three times in Gibraltar and has also
been trapped and ringed at the Jews’ Gate
Observatory. It has in addition been recorded
in the vicinity, most notably the one found
inside the Carrefour supermarket in Los Barrios
by our Bird Report editor Ernest Garcia (see
Gibraltar Bird Report vol. 5).
Other Asiatic species over the years have
included a pair of Pine Buntings Emberiza
leucocephalos found on Windmill Hill, the
Little Bunting Emberiza pusilla trapped at the
Observatory last September, Pallas’s Warbler
Tropical Mockingbird
Phylloscopus proregulus, Dusky Warbler
Phylloscopus fuscatus, several Siberian
Chiffchaffs Phylloscopus collybita tristis and a
Mountain Chiffchaff Phylloscopus sindianus.
These birds, mainly juvenile and inexperienced,
confuse their orientation on migration and find
their way to distant locations instead of familiar
wintering-grounds. Weather may play a part
in this as well, but it is an incredible feat given
that many of these species winter in South or
Southeast Asia.
At the other end of the spectrum are
Nearctic migrants that fly down the eastern
coast of North America to their wintering
grounds in the Caribbean and South America.
Here, westerly depressions and storms displace
some over the Atlantic where they either manage
to make landfall in Europe, succumb, or
land on a ship and survive the journey until
they are in sight of land. Many small passerine
migrants must be ship-assisted and some have
found their way to Gibraltar. In May 1986 a
White-throated Sparrow Zonotrichia albicol-
Charles Perez & Keith Bensusan
lis and a Dark-eyed Junco Junco Hyemalis
were found, after a foggy night, at the North
Mole. The location indicates a ship-assisted
provenance, as is the case with the discovery
this spring of a Tropical Mockingbird Mimus
gilvus in the Watergardens area close to
the Mole. Other Nearctic species, such as
Bobolink Dolichonyx oryzivorus and Indigo
Bunting Passerina cyanea were trapped in late
April and early May. One can only wonder
whether these had crossed the Atlantic during
the autumn as is more usual for these birds,
and then perhaps wintered in Europe or Africa.
Ship-assisted passage from the
Mediterranean was also attributed in the discovery
of a House Crow Corvus splendens in
March 1991, found flying around the cliffs at
Europa Point and discovered shortly after the
arrival of the Royal Navy’s task force from the
Middle East. This species is an example of
how birds may benefit from ship assistance: a
native of South and Southeast Asia, it has taken
advantage of shipping movements in the Indian
Ocean to spread to Arabia and East Africa.
Indeed, there are scattered records of House
Crow around the coasts of Europe and the
species has been breeding in the Netherlands
since 1998. All of these birds have been ship
assisted.
Many tropical African birds are practically
sedentary. However, those that occupy
habitats that are subject to large fluctuations
in resources perform considerable nomadic
movements in areas south of the Sahara.
The desert is a formidable obstacle for most
birds, as are the Atlas mountain ranges of
Morocco. Nevertheless a juvenile Allen’s
Gallinule Porphyrio alleni overshot and arrived
at Gibraltar on the 13th December 2001, the
first of several that were recorded into Europe
during that period. Such overshoots are
perhaps not surprising given the considerable
movements that aquatic species perform whilst
tracking water in the Sahel and Savannah belts
of West Africa. Many sub-Saharan African
passerines have been recorded in Gibraltar
over the years, such as Waxbills Estrilda spp.,
Weavers Ploceus spp., Wydahs Vidua spp.,
Cut-throat Finch Amadina fasciata and Redbilled
Quelea Quelea quelea. Due to these
being granivores that are popular as cage
birds, they have traditionally been considered
escapees, but the capacity of these for seasonal
movements is considerable (the Red-billed
Quelea being a famous case in point) and
ship assistance of occasional birds is possible.
Many of these are seen at Europa Point, which
makes you wonder. Some escapees such
as the Common Waxbill Estrilda astrild have
established small populations in southern Iberia
that have now been present for many generations.
Sporadic records of these in Gibraltar,
including two at the Convent Garden on the
16th June 2012, would indicate that feral birds
could become established on the Rock too.
Some North African species have altitudinal
movements to wintering grounds north or
south of the Sahara desert, and when returning
north have been recorded in Gibraltar.
This was the case for a Tristram’s Warbler
Sylvia deserticola and a Seebohm’s Wheatear
Oenanthe oenanthe seebohmi seen on
Windmill Hill on the 10th April 1988 and 28th
April 2005 respectively. A Desert Wheatear
Oenanthe deserti seen on Windmill Hill Flats
on the 3rd September 1987 could also have
been North African (subspecies homochroa).
African Chaffinches Fringilla coelebs africana
have also been trapped at the Jews’ Gate
Observatory on the 28th March 1986 and the
9th April 2004, and constitute the only records
of this subspecies for Iberia.
Seabirds tend to be displaced from their
breeding and wintering grounds by inclement
weather systems, but fare better and are more
resilient at sea and survive to arrive in unfamiliar
territory. There have been three records of
immature Laughing Gulls Leucophaeus atricilla
from North America in autumn 1990 and in
spring 1997 and 2004. A Grey-headed
Little bunting
Gull Chroicocephalus cirrocephalus, a tropical
African and South American species, was
recorded on the 17th August 1992 and an
Iceland Gull Larus glaucoides was seen after a
cold spell on the 14th and 15th January 1987.
An exceptional vagrant is the only record for
Europe of a Cape Petrel Daption capense, a
common species from the southern oceans,
which was seen below Europa Point on 20th
June 1979.
Species of ducks and divers from the far
north were occasionally recorded in the area
of the Strait of Gibraltar by Lt. Col. Irby in the
1800s but have remained undetected recently
since the mid 1900s. Exceptions to this include
two records of Great Northern Diver Gavia
immer, one seen off Europa Point on 23rd
November 1999 and the other off Sandy Bay
on 31st December 2000.
With climate change as a precursor of
global trends, we may well see the behaviour
of many bird species begin to change as a
result of adaptation. Already in our short
lifetime, some species have begun to arrive at
their breeding grounds earlier, expand their
distribution northwards, or winter north of the
Sahara. Records of Lanner Falco biarmicus
erlangeri and Long-legged Buzzards Buteo
rufinus cirtensis, both North African subspecies,
have increased in the last 10 years, with the latter
now found breeding in southern Spain, and
Short-toed Circaetus gallicus and Booted Eagles
Hieraaetus pennatus regularly winter in increasing
numbers in Iberia. We may find that these
adaptations may lead to changing patterns of
vagrancy that may provide an insight into the
dramatic environmental changes that are occurring
in the world in our lifetime.
GIBRALTAR NATURE NEWS
3

GIBRALTAR NATURE NEWS
4
The foundations of the binominal nomenclature,
or scientific name, by which living species are
categorised and identified, were laid down by the
Swedish botanist Carl Linnaeus (1707 - 1778) and
for this he is often referred to as the father of modern
taxonomy. This system of naming is the internationally
accepted form of identifying and classifying species.
For example the scientific name of the endemic
Gibraltar campion is Silene tomentosa. This makes
clear that the plant belongs to the genus Silene, and
of the many hundreds of species that belong to this
genus, the Gibraltar plant is the species tomentosa.
Botanists world-wide will know exactly which species
is being referred to, and there will be no confusion.
Simply referring to the common name is not
very useful as the common name of a plant will differ
from country to country and even between different
regions within a country.
However, things are not as straightforward
and uncomplicated as all this! Over the last few
years, various botanical entities and organisations
such as ICBN (the International Code of Botanical
Nomenclature), IPCN (Index to Plant Chromosome
Numbers), PESI (Pan-European Species directories
Infrastructure), APG (The Angiosperm Phylogeny
Group), and others have been working at standardising
and eliminating errors in the naming of
plant species. This has resulted in the accepted
scientific names of many species having to be
altered, in some cases only slightly and in others
Tripodion tetraphyllum
Rhodalsine geniculata
NAME CHANGES
Leslie Linares
quite drastically, sometimes involving placing a
species under a different or new genus or family.
There are various reasons for the need to make
these changes. The simplest of these arises because
of the existence of different spellings for the same
species name. These are known as orthographic
variants, and a decision has to be made as to
which is the accepted spelling. Examples of this are
Bidens aurea becoming B. aureus, Melilotus indica
becoming M. indicus, and Amaryllis bella-donna
becoming A. belladonna.
The most common and significant changes
arise from the existence of synonyms. A synonym
is a scientific name applied to a species that now
goes by a different scientific name. This can arise
for various reasons, such as that the same species
was named independently by different authors.
There are various categories of synonyms, depending
on whether they are derived from the same
type specimen (homotypic synonyms), or from
different types (heterotypic synonyms). Changes
arise when a decision is made as to which one is
to be considered the correct one. This may depend
on the opinion of the author, but usually priority is
given to the name first published. For example the
Gibraltar campion was named Silene tomentosa
by Otth in 1824 and Silene gibraltarica by Boissier
in 1838, so priority goes to Otth.
Occasionally, a taxon which originally had
been classified as a subspecies is raised to the
Solanum linnaeanum Jacobaea maritima
Drimia maritima
Dioscorea communis Ornithogalum baeticum Moraea sisyrinchium
level of full species. Such is the case of the Star
of Bethlehem (Ornithogalum orthophyllum subsp.
baeticum) which has become O. baeticum.
Sometimes it is found that there is a species
which has a name which is identical in spelling
to another such name belonging to a totally different
species. These are known as homonyms. The
International Code of Botanical Nomenclature specifies
that, as the case above, the first published of
the two homonyms is to be used as the correct one.
A later homonym is considered illegitimate, and so
the species has to be given an alternative name.
When the scientific name is changed, and
the new name is based on a previously publicised
legitimate synonym, the earlier name is known as a
basionym of the species.
Important fundamental changes occur when a
species is placed under a different genus or even a
different family, as a consequence of DNA analysis.
Lastly, sometimes it is found that some species
have been associated with a wrong name and
never corrected, or due to confusing circumstances,
it is not clear which was the original type that got
the name by which it is known. This is the case of
Solanum linnaeanum, which, because of confusion
about what species the original Solanum sodomeum
of Carl Linnaeus referred to, a new name
honouring Linnaeus was chosen.
Here are some examples of recent changes
made to the well-known names of common species:

Acis autumnalis Bidens aureus
Common name Previous name or synonym New accepted name
Bladder vetch Anthyllis tetraphylla Tripodion tetraphyllum
Upright or stiff brome Bromus rigidus Anisantha rigida
Crown daisy Chrysanthemum coronarium Glebionis coronaria
Barbary nut Gynandriris sisyrinchium Moraea sisyrinchium
Autumn snowflake Leucojum autumnale Acis autumnalis
Pink sandwort Minuartia geniculata Rhodalsine geniculata
Osyris Osyris quadripartita Osyris lanceolata
Kikuyu grass Pennisetum clandestinum Kikuyuochloa clandestina
Annual meadow-grass Poa annua Ochlopoa annua
Pitch trefoil; Bitumen pea Psoralea bituminosa Bituminaria bituminosa
Autumn squill Scilla autumnalis Prospero autumnale
Cineraria Senecio cineraria Jacobaea maritima
Esparto grass Stipa tenacissima Macrochloa tenacissima
Black bryony Tamus communis Dioscorea communis
Winged or asparagus pea Tetragonolobus purpureus Lotus tetragonolobus
Sea squill Urginea maritima Drimia maritima
Glebionis coronaria
Silene tomentosa
Bituminaria bituminosa
Prospero autumnale
NOTES
& NEWS
EUROPA POINT MOUND
As a result of the cessation of all weeding and
planting at the mound at Europa Point, much
of the natural vegetation of the site made a
welcome return this Spring. Though some of
the original species re-appeared in reasonable
number, others remain absent. Imported soil
was used to cover the mound, and as a result
a number of introduced species also made an
appearance. These may or may not survive
the coming winter storms, only time will tell. In
total, over 100 species have been recorded
from the site. What is important is that there
should be an interpretation board at the site,
explaining the fact that the site has been left in
a natural state, and not landscaped as other
areas at Europa Point. A more detailed report
on the mound will appear in the next issue of
Nature News.
JELLYFISH INVASION
This summer the jellyfish invasion reached
enormous proportions. The species, the Mauve
Stinger Pelagia noctiluca, has a nasty sting and
swimming was banned on some of our beaches
to prevent swimmers from being stung. The
problem was exacerbated by increasing water
temperatures in the Mediterranean in recent
years, and was mainly prevalent in areas of
the Spanish coastline around the Costa Blanca
and Costa del Sol. The cold currents from the
Atlantic gave Gibraltar a respite, but in recent
years, and with easterly conditions blowing
warm surface waters close to the shoreline,
the invasion has reached our shores. Sightings
earlier in the year have included the venomous
Portuguese Man o’ War Physalia physalis,
not a jellyfish but also a cnidarian with similar
habits.
LETTERS FOR NATURE NEWS
Please remember you can start sending in
letters either by normal mail to Gibraltar
Ornithological & Natural History Society, PO
Box 843, Gibraltar or by email to editors@
gonhs.org for the next issue of Nature News.
Letters can be about your views or comments
related to nature, or to ask questions
to GONHS Council. The sender of the first
letter received for each Nature News issue
will receive a FREE copy of the great book The
Flowers of Gibraltar written by Leslie Linares,
Arthur Harper and John Cortes! Letters must
have bona fide names (and remember to
include your contact details in case you qualify
for the free book).
GIBRALTAR NATURE NEWS
5

GIBRALTAR NATURE NEWS
6
Wildlife photography has grown with the
advent of the digital medium in the last decade and
has led to an increase in the popularity of this hobby
in recent years. From distant subjects captured with
telephoto lenses to close-ups with macro lenses,
the results can now be displayed instantly on the
web and has resulted locally in the creation of the
Facebook page ‘Gibraltar Wildlife Photographers’
earlier this year.
This is a closed group that displays the work
of many accomplished photographers, where you
can post pictures taken anywhere in the world
of plants, animals and landscapes. You can
request to join at http://www.facebook.com/
groups/390212081002774/. The only criterion
for joining is that you must have a Gibraltar connection.
Some local photographers have also created
their personal websites and blogs, where they post a
photographic account of their trips to the countryside
in Gibraltar and nearby in Spain. Among a few
examples of some of these sites is ‘Bird Nerds’, created
by father and son John and Gareth Henwood.
They have been posting examples of their work since
the late summer of 2010 and their blog is dedicated
to bird species found in areas of Southern Spain and
the area of the Strait of Gibraltar. Many of their
expeditions have taken them to traditional birding
hotspots such as La Janda, the Palmones estuary, the
Sancti Petri wetlands near Cadiz and the saltpans
Late last year the GONHS and the Royal
Gibraltar Regiment, together with the representatives
of the Defence Estates in Gibraltar, and the MOD’s
Janitorial Section held a very fruitful meeting on
Windmill Hill to assess prospective habitat management
works at the site.
For some time now the GONHS had been
highlighting the plight of vegetation succession on
Windmill Hill, with dominant Olive bushes forming
thickets of impenetrable scrub, threatening areas of
floral diversity. Many of the pathways had been
smothered by encroaching woody vegetation, with
some completely disappearing in the last few years.
The Regiment had also identified some of these areas
as priorities for vegetation clearance as it prevented
access and constricted their training to just a few
locations.
Four main areas for habitat management were
identified, with one particular area where the growth
of the species Warty Spurge Euphorbia squamigera
was being restricted by the Olive scrub. This species
is prevalent close to cliffs, and forms a habitat type
of European importance that is designated under
the Habitats Directive. Minor clearing either side
of existing pathways was also recommended. In
LOCAL WILDLIFE WEBSITES & BLOGS
Charles Perez
of Bonanza. They also have a photographic record
of a visit to Doñana and even took their cameras
to Iceland earlier this year. Birders interested in
visiting some of these habitats can get a feel of the
place by visiting the website on http://bird-nerds.
blogspot.com/.
Another unique blog is hosted by Clive
Finlayson of the Gibraltar Museum and his family,
all keen wildlife photographers. They have
posted their work under the title ‘Finlayson Nature
Photography’, which covers visits to the surrounding
countryside in Spain and Gibraltar, as well as further
afield including the Pyrenees and the Farne Islands.
Some of their photographic accounts are dedicated
to specific diaries of species, drawing on texts written
by historic naturalists of the 19th and 20th
centuries and comparing them to the present. They
also depict behavioural aspects of some species,
including Chiffchaffs feeding on the nectar of Aloes,
Honey Buzzard migration, an Arctic Tern colony and
feeding frenzies of Common Dolphins and Cory’s
Shearwaters in the Strait. The blog also includes
features on the Spanish Ibex and the Lammergeier.
Entries are accompanied by magnificent land and
WINDMILL HILL COLLABORATION
Charles Perez
addition to this, the Regiment suggested the clearing
of woody vegetation to form wide open corridors on
the south-eastern slope, and we suggested this could
be carried out elsewhere on the site.
At the meeting the GONHS also highlighted
areas where rubble accumulations had built up in
recent years, some of which had been deposited on
natural vegetation, and areas where rubber pellets,
contaminated with spent bullets, had been illegally
dumped at the site. Emphasis was also given to the
removal of stands of invasive species, such as the
Hottentot Fig Carpobrotus edulis, the Century Plant
Agave americana and the spread of the invasive
grass Kikuyuochloa clandestinum on the site. As is
customary, the GONHS advised that works should
be carried out outside the bird-breeding season; from
July to February.
The MOD Janitorial Section, under the leadership
of Emilio Wink, soon carried out habitat management
works and by late winter a large corridor
on the slopes was brimming to full capacity with
flowering plants, including the colourful Giant Squills
Scilla peruviana and Paper-white Narcissus Narcissus
papyraceus from bulbs that had remained dormant,
hidden in the dense scrub. Several pathways were
seascapes to depict wildlife in its natural environment.
You can enjoy this blog on http://naturalandalus.blogspot.com/.
As this is a GONHS magazine, pride of place
must go to the GONHS website, which keeps the
membership informed of news, press releases, recent
records of sightings of birds, other fauna, and lists of
the fauna and flora of Gibraltar that are frequently
updated. Recently, the GONHS has established a
Facebook page, which has proved extremely popular.
Photographs are posted regularly and members
have the opportunity to ask questions that can then
be answered by experts or other enthusiasts. In
fact, as outlined in the Editorial, future editions of
‘Gibraltar Nature News’ will carry a selection of
questions and answers that that have been posted
on the GONHS Facebook page.
You can ask to join the group at http://www.
facebook.com/groups/gonhs/.
also exposed, with vegetation cleared several metres
either side and this provided the conditions for many
flowers to germinate.
The Regimental site officer WO2 Jimmy
Canessa, was also instrumental in providing skips
at the site, and several rubble accumulations were
removed as well. Other sensitive issues on Windmill
Hill include the removal of palm trees that have germinated
on seeds carried in the faeces of gulls, and
widely dispersed at the site, the control of feral cats
that have drastically reduced the numbers of Barbary
Partridges, habitat management on the firing ranges
and the adjoining embankments, and the sensitive
use of pyrotechnics in the dry season. Regular contact
with him since then has improved lines of communication
with the MOD and augurs well for the future.
The MOD are also looking into the implementation
of a management plan for Windmill
Hill, and a draft has already been circulated for
consultation purposes. One particular issue that
the GONHS had raised on numerous occasions,
and will be resurrected once the plan is in place,
is the MOD Conservation Group, which will ensure
sound management practises at this ecologically
sensitive site.

UPPER ROCK TEAM CONTINUES TO
WORK FOR GIBRALTAR’S FLORA
Wildlife (Gibraltar) Ltd’s Upper Rock Team has again been doing some excellent work maintaining and
creating habitat on the Upper Rock. This is being done in tandem with their responsibility to maintain paths
and some structures within the Nature Reserve. Works carried out include the following:
Bruce’s Farm Firebreak
The clearing work carried out by the
team along the old Bruce’s Farm firebreak
has been reported in previous issues of
‘Gibraltar Nature News’, including the welcome
comeback of plants typical of the site
such as Greater Catmint Nepeta tuberosa
and Rampion Campanula rapunculus. This
work consisted mainly of clearing and
renovating the old Inglis Way footpath, but
recently the Upper Rock team have been
more ambitious in their aims. In 2011, the
team began to clear sections of the old,
abandoned firebreak around Bruce’s Farm.
In the winter of 2012, this culminated in
the clearing of all woody vegetation except
Dwarf Fan Palms Chamaerops humilis from almost
half of the original area. Although still too soon
to witness the full extent of the restoration of this
habitat, the results are already impressive. During
the spring, the area was alive with flowers including
an abundance of Rose Garlic Allium roseum and
Jersey Buttercup Ranunculus paludosus, as well as
some Barbary Nut Moraea sysirinchium. The flora
in this area will only improve as time progresses and
management is maintained.
Roadsides
Similar clearing work has been carried out
along roadsides on the Upper Rock. This will be of
huge benefit to flora and associated fauna within the
Nature Reserve and the results will be seen come
springtime. The clearings will also afford visitors to
the Upper Rock areas where they can sit away from
the immediate roadside and enjoy some shade.
These works have also exposed historic walls and
some of the anchor rings used to transport large guns
to the top of the Rock.
Euphorbia characias subsp. characias
Many of the plants that are typical of open
areas are becoming increasingly rare on the Upper
Rock due to a lack of maintenance or adequate
management of open areas such as firebreaks and
roadsides. It is with this in mind that the Upper Rock
Team has been carrying out the work described
Queen’s Road clearing
- Historic Wall Exposed
Keith Bensusan
The Team
above. One such plant is the Mediterranean Spurge
Euphorbia characias subsp. characias. This attractive,
shrubby plant with its thick, reddish stems and
lime-green inflorescences has become increasingly
rare in Gibraltar as a result of habitat loss. Perhaps
the most important population on the Rock lies along
Signal Station Road. Here, its habitat was becoming
increasingly encroached by the maquis, but not any
longer, as the Upper Rock Team has cut through
swathes of woody vegetation that will allow existing
plants to develop as well as to distribute their seeds.
They have also identified additional plants that were
not known to GONHS.
Sand Slopes
The spread of invasive Australian Acacia species
seems to be relentless on the East Sand Slopes. The
Upper Rock Team spent some time clearing encroaching
patches of Acacia on this interesting and important
habitat, which is protected under the EU Habitats
Directive. Gibraltar has an obligation to adequately
conserve this habitat and it is only through work such
as this that we will be able to do so.
The Upper Rock Team consists of Reuben Senior,
Al Marfe, Jimmy Alman, Arthur Asquez, Christian
Asquez, Matthew Dignam, Teresa Nankani and
Christian Ressa.
Repairing Mediterranean Steps
NOTES
& NEWS
NAVAL AERIAL
In March, GONHS discovered that works
were proceeding to clear a large area of
vegetation on Windmill Hill Flats, an area
designated as a Site of Community Interest
under the EU Habitats Directive. Upon further
inquiry, it was revealed that the MOD were
in the process of clearing the area for the
erection of a very large aerial array to service
the requirements of the Navy’s signal station
at the site. GONHS soon stopped the works
and the MOD was instructed by the Ministry
for the Environment that due process had not
been followed and that any such works at the
site would require an Appropriate Assessment.
The footprint of this aerial would cover a large
area and included 10 masts with three ties
each that would form a network of cables. It
could have an impact on night migrants and
the resident Barbary Partridges. It would also
be situated within an area where a Habitat
Type of Community Interest is located.
Ramboll (Gibraltar) Limited are in the process
of preparing an EIA Screening Report and
a Habitat Regulations Assessment Screening
report in which GONHS has supplied information
on the importance of the ecological
features of the site. We eagerly await the
results of these reports.
PALM WEEVIL UPDATE
The Red Palm Weevil Rhynchophorus ferriguneus
continues to infect palms around
Gibraltar. These large, striking beetles are
becoming an increasingly common sight in
Gibraltar and the occasional palm unfortunately
succumbs to attacks. However, the
Gibraltar-wide treatment programme that
began last year appears to be paying off,
with many palms surviving or even recovering
from attacks and considerable damage.
POLISH ORNITHOLOGISTS
VISIT GIBRALTAR
Prof. Piotr Tryjanowski (Poznan University of
Life Sciences) and Dr. Piotr Zduniak (Adam
Mickiewicz University, Poznan) visited
Gibraltar in early November to carry out collaborative
work with ornithologists from the
Gibraltar Ornithological & Natural History
Society. Prof. Tryjanowski and Dr. Zduniak
are experts on bird migration science, including
the effect of climate change on bird migration.
They visited Gibraltar to start preparing
scientific analyses on migrating birds, using
the extensive database of records gathered
by the bird ringing operation coordinated by
GONHS, which now spans a period of twenty
years and includes some 70,000 records of
birds that have been ringed or recaptured on
the Rock.
GIBRALTAR NATURE NEWS
7

GIBRALTAR NATURE NEWS
8
The problem with macro photography has
always been that the closer you focus on a
subject, the less depth of field or area in focus
that appears acceptably sharp in the image that
you take. This can be compensated to a degree
by increasing the depth of field by stopping
down the lens, increasing your f. stop, but it will
decrease the amount of light being received by
the sensor, and increases diffraction, and on
very small subjects will not ultimately result in a
fully focused image.
Photo stacking is the technique that resolves
this, and is used to produce a sharp macro pho-
PHOTO STACKING
Charles Perez
tograph throughout the focus range required
of the subject, by stacking several partially
focused images, and combining the focused
areas of the images into one final photograph.
The technique that is applied here is to take multiple
photographs of a single subject throughout
the focus range, from the closest focused part
of the subject to the furthest area that is needed
to guarantee that the final picture produced
will all be in focus. You will obviously require
mounting the camera on a sturdy tripod and
taking pictures using a shutter release to minimise
vibration. This will ensure that all photo-
graphs of the subject will align with each other
within the focusing range required. This can be
achieved in the field, but for best results you can
take the subject home and manipulate it using
selective lighting, backgrounds and choosing
the best angle to accomplish the final image.
The last few issues of Nature News have
covered several insect groups that have been
depicted using the stacking technique. Some
of the larger subjects have been taken using
ordinary macro lenses, whereas other smaller
ones have required the use of extension rings
and/or bellows to achieve a closer focusing of
the subject. Others have been taken through a
trinocular microscope, where the image is transmitted
through a third eyepiece onto the sensor
of the camera. By adjusting the focus plane
and taking multiple images the results can then
be transferred onto the stacking software for the
production of the final image.
This technique is incorporated into
advanced photographic software programmes
that resolve complex mathematical algorithms
to select focused pixels and combine them,
adjusting the x and y axes of each photograph
so that combinations are aligned and stack
perfectly into each other providing a final accurate
focused image of all the combined photographs.
For large subjects, close-ups of flowers
or a medium sized insect for example, a stack
of 8-10 photographs will suffice, depending on
the orientation of the subject, but the smaller
the subject, the more photographs that will be
required to complete the final picture.
The picture of the small yellow flower was
composed of 20 exposures at different focusing
levels and combined to produce the final
image. I have included two images in between
the focusing range where you can appreciate
the limited depth of field. Note the geometrid
caterpillar on one of the florets to the right. The
other pictures show the result of this procedure
used on other plants.
There are several software products that
you can choose to practise with. One of the
pioneers of stacking software was developed
by Alan Hadley who provides the free software
programme called ‘Combine ZP’. You can
install the programme from the site http://
www.hadleyweb.pwp.blueyonder.co.uk/CZP/
Installation.htm .
Another stacking programme, and the one
we use here at GONHS is ‘Helicon Focus’.
This programme is not free, but is extremely
user friendly and also provides an excellent
retouching programme where you can adjust
and correct slight inconsistencies and glitches in
the finished product. The programme has two
different methods of stacking using weighted
average and depth map, and you can adjust
the radius of the focused edge of pixels and
incorporate smoothing to the process so that
by applying different settings you can ultimately
produce the best image that suits your needs.

The programme is available at http://
www.heliconsoft.com/heliconfocus.
html. Helicon Focus also provides
other software options including one
called Helicon Remote that will automate
focus bracketing, and also allow
combined exposure and focus bracketing
and perform tethered shooting via
USB cable. They also provide ‘Helicon
3D viewer’ a free utility that helps to
visualize a stack of images as an interactive
3D model.
Helicon Focus also recommends
a fully automated focus-stacking rail,
‘Stackshot’, that works by an electronically
controlled macro-rail that
coordinates the movement of the rail
and automatically triggers the camera
shutter. All you have to do is set the
number of exposures required and provide
the closest and furthest focusing
distance and Stackshot will do the rest.
In our next issue I will describe a
technique for taking super close-ups of
minute subjects; micro-photography for
the closest pictures possible so far.
NOTES
& NEWS
RAVEN’S DEMISE
Ravens have been a feature of Gibraltar since
the turn of the century. The last nesting pair
disappeared in the early 1970s but a pair
colonised and attempted nesting in 2001.
However following several attempts over the
years, we discovered that one individual was
missing a foot and this possibly contributed to
its lack of breeding success.. Nevertheless it
was always a welcome sight to see these magnificent
birds chasing Yellow-legged Gulls and
raptors, foraging around the Rock and landing
on the Clifftops roof where observers at Jews’
Gate would admire their antics.
In May of this year, we received a report
that one of the Ravens had been found dead,
hanging by a leg on cliff stabilisation mesh
below Buena Vista Barracks. A visit to the site
confirmed the loss of one of these wonderful
birds, which must have got snagged in the
wire mesh.
GONHS has always been very critical of the
use of cliff stabilisation mesh, especially in
locations that birds utilise for breeding and
roosting. We have always insisted that a
wide diameter is used so as to accommodate
nesting Blue Rock Thrushes and allow small
passerines access to this habitat. Nevertheless
there have been instances when Yellow-legged
Gulls have become trapped behind the mesh.
In such cases, the Caves and Cliffs Section
have then extracted the birds and ensured that
the gaps are minimised. However, this last
instance with the Raven illustrates that these
meshes pose a peril to larger birds.
RECORD RINGING YEAR
The total number of birds trapped and ringed
in Gibraltar in 2011 was a staggering 7901
and included 7041 new birds. This total
included 47 birds ringed in the Botanic
Gardens during Eurobirdwatch day and a further
four birds trapped on the Upper Rock. All
credit goes to the immense efforts of resident
ringers Steve Norman who manned the site
during the spring, Ian Thompson & Yvonne
Benting who did a stint in the heat of the summer
and returned to cover November till the
end of the year, Robin and Julia Springett who
covered January and much of September, and
Ray Marsh who did his traditional four weeks
during the October period. Thanks are also
due to all those other local and visiting ringers
who helped out. A full report in greater
detail will be published in the 2011 Gibraltar
Bird Report.
APOLOGIES
The editorial team would like to apologise to
members for the delay in the publication of
Nature News this year. This has been due
to the restructuring of GONHS Council and
delegation of its duties, as well as critically
examining the format of Nature News, which
will in future incorporate other features of interest
and feedback from the membership. The
2011 Bird Report is almost ready and will be
posted to the membership in the autumn.
GIBRALTAR NATURE NEWS
9

GIBRALTAR NATURE NEWS
10
FISHING DISPUTE CAUSES GONHS SERIOUS CONCERN
GONHS was the first NGO to fully support Government’s position
when the Government decided to do away with the illegal 1999 Fishing
Agreement, as they intimated they would in their Manifesto and put in
practice in March of this year. We issued a press release that was published
in both the Panorama (14th March) and the Gibraltar Chronicle
(15th March) which stated that: ‘GONHS very much welcomes the
Government’s position on the 1991 Nature Protection Act as confirmed
by the Minister for Health and the Environment, Dr John Cortes, who has
stated that: ‘the Government stands firmly by the provisions of the 1991
Nature Protection Act and that the RG Police is aware of this.’
So what has happened after? Everybody in Gibraltar will be aware
that we have had illegal fishing in British Gibraltar Territorial Waters by
Spaniards since then, that the Guardia Civil have unlawfully entered our
waters both to protect the fishermen fishing illegally in our waters as well
as to taunt and provoke the RGP, GDP and even the Royal Navy vessels
who repeatedly instruct them to leave our waters. The Guardia Civil
ignores these warnings and continues its unlawful presence until its vessels
decide to leave of their own accord. There has even been an act of piracy
perpetrated by the Guardia Civil when its officers boarded a Gibraltar
boat 200 metres from Europa Point, towed it to Algeciras and detained its
occupants. These incidents are serious and worrying as they undermine
effective law enforcement by those who are meant to carry this out within
our waters: British and not Spanish authorities.
Clearly there is a lot more going on than the Spanish protecting what
they see as their rights to fish in our waters- which in fact is not a right at
all. They fish with nets and rakes that are illegal and have been for over
twenty years. When the fishermen were given the option to come to talk
to the RGP so they could be told why they could not fish in our waters any
longer, the RGP unwittingly opened Pandora’s Box. They translated, typed
out and presented to Government the fishermen’s ‘back of an envelope’
hand-written proposal that the fishermen thought would allow them to
keep fishing here. This generated the months of talks and fine-tuning that
would see the fishermen dealing directly with our Government, something
that would not be entertained in any other country. The fishermen even
gave our Government deadlines by which the Expert Working Group,
subsequently set up by Government to meet with the fishermen, had to
arrive at a date when they would start fishing again. Once Pandora’s
Box was opened insidious Spanish politics, both from the immediate
hinterland as well as from Madrid, came to the fore: the stage was set to
directly challenge Gibraltar’s jurisdiction of its waters. Our political and
other social media sites, one with over 7,300 members, are alive with
debates, discussions and views on this issue.
GONHS will provide a full assessment of the outcome of the talks
between the Working Group and the fishermen, and of the report and
findings of the Group. The Government will use the report to arrive at
a decision on fishing issues in Gibraltar. GONHS will also provide a
background and context as to why it thinks Gibraltar has been put in the
difficult position it has been both by Spain, who are known to flout fishing
regulations in their own country as well as in many others (Canada, the
UK and Morocco for example) as well as by the UK, who do not seem to
have done very much to protect our waters.
But we cannot do this until talks have ended, the full report is available,
and the Government announces its final decision. As a Natural
History society that also doubles up as a Conservation and Environmental
RHIAN LEADING RESEARCH ON ANTS
GONHS Invertebrate Section member Rhian Guillem had an
important paper entitled “Using chemo-taxonomy of host ants to help
conserve the large blue butterfly” published in the prestigious journal
Biological Conservation. The paper reports the findings of a study,
carried out as part of Rhian’s PhD with the University of Sheffield,
which aimed to simplify identification of ants that are tricked into rearing
the Large Blue Butterfly Phengaris arion by its caterpillars.
The Large Blue is a globally threatened species that became extinct
in the UK in 1979. Since then, populations have been reintroduced in
Great Britain but its status is still fragile.
As part of its life-cycle, the caterpillar of the butterfly is adopted by
Myrmica ants, which it tricks by smelling like the larvae of the ants and
Alex Menez
Pressure Group, we must put forward our views related to conservation.
We are encouraged when we re-read Government’s Manifesto and see
what they said there: ‘We will establish an Environmental Enforcement
Team which will work at sea in protecting our natural habitat from foreign
fishermen and divers who do not respect our environment and the
biodiversity in the waters around Gibraltar’ (page 33), and: ‘We do not
believe it is right to allow illegal fishing in our waters and we will stop this
immediately. We will ensure that the ban on use of drift nets and other nets
is enforced without political interference to prevent the proper policing of
and - in keeping with the commitments we have given the GFSA, we will
ensure the proper regulation of fishing (and diving) to ensure conservation
as the top priority.’ (page 43). And despite views by some that the
1999 Fishing Agreement was not illegal we need only turn to the Nature
Protection Act Section 10 ‘Prohibition of certain methods of killing or taking
wild animals.’ which states that ‘...if any person – ‘(b) uses for the purpose
of killing or taking any wild animal.... any seine or gill net, any pot or
device for killing or stunning...’ and: ‘(f) knowingly causes or permits to be
done an act which is mentioned in the foregoing provisions of this subsection,
shall be guilty of an offence.’ (f) clearly shows that the Agreement,
by allowing these, is in direct contravention of the Act and is not lawful.
GONHS acts on facts and evidence, and the fishing issue is no different
to any other in this regard. Fortunately, the Government has also
acted on facts and evidence in the fishing issue. GONHS is delighted,
and fully supports, Government’s decision based on the preliminary report
of the Working Group. In its Official Release, issued on the 16th August,
Government has clearly stated its position: ‘In the circumstances, and
based on the recommendations of the Preliminary Report, the Government
has to maintain its current position requiring full observance of the provision
of the Nature Protection Act 1991. The Government will, therefore,
not grant any permit to allow fishing with nets in British Gibraltar Territorial
Waters in contravention of section 10 of the Act. Also in keeping with
the Preliminary Report recommendations, the Government will continue to
work with the experts involved to develop robust monitoring and assessment
programmes to evaluate, manage and protect the marine environment
around Gibraltar.’ It is clear from the findings of the Preliminary
Report that commercial fishing cannot be permitted in Gibraltar: ‘Based on
the lack of complete and critical information on which sound fisheries management
measures and actions can be based, a precautionary approach
is recommended at this time. The level of uncertainty associated with most
of the species including whether some species spend part of their life
cycle in BGTW (for example, during their juvenile or breeding stage) and
the impacts of fishing methods on the marine environment within BGTW,
provides sufficient evidence to support a moratorium on commercial fishing
within the BGTW. Robust monitoring and assessment programmes need
to be established and implemented to collect and evaluate the marine
environment around Gibraltar and provide a basis for robust management
actions. It would be prudent that, until such time and when the supporting
legislation and framework for implementing fisheries conservation and
management measures are in place, the Gibraltar Government maintains
its current position on prohibiting commercial fishing in BGTW.’
As a very good friend of GONHS and the environment said very
recently of the fishing issue: ‘Science will prevail.’
Alex Menez
emitting sounds like a queen ant. However, caterpillars only develop
well in the nests of Myrmica sabuleti, usually dying in the nests of the
closely-related Myrmica scabrinodis. These ants are very difficult to
tell apart visually, even for trained experts, but Rhian and her team
have discovered that hydrocarbons found on the surface of the ant can
be used to distinguish the two species. This is crucially important to
reintroduction programs, as successful reintroductions depend on the
correct proportion of M. sabuleti being present at the site. The new
method allows surveys of Myrmica ants at proposed reintroduction
sites to be carried out accurately and efficiently. The importance of
the study is such that Planet Earth Online, the online magazine of the
Natural Environment Research Council (NERC), carried an article on

CAPTIVE BREEDING PROGRAMME
For several years now the Raptor
Rehabilitation Unit has embarked on a captive
breeding programme of raptors. Among the
species chosen have been the local subspecies
of Peregrine Falco peregrinus brookei which is a
slightly smaller bird than the nominate race, and
the Lesser Kestrel Falco naumanni.
Initial trials with the Peregrine were unsuccessful
due to a number of factors ranging
from inadequate breeding chambers leading to
captivity stress, non-laying females and non-copulating
males. The global percentage of success
of breeding wild adult falcons has always been
very low, but it was found that by constant training,
the birds imprinted to their surroundings and
human carers and this made it easier for them to
accept their situation and finally breed successfully.
The first trials after this produced infertile
eggs from one female, due to the male being
either too old or unable to maintain a healthy
courtship and copulation. A second attempt in
2004 using artificial insemination was successful
and the first captive-bred Peregrine in Gibraltar
was finally reared.
A captive male Peregrine was acquired from
Spain and the bird was paired with the female,
but copulation was again unsuccessful and the
first clutch of four eggs was found to be infertile.
Artificial insemination, although time consuming,
was tried again, and this time three out of a
clutch of four were found to be fertile. Two died
at birth but the third was finally fledged, trained
and released back to the wild.
It is believed that lack of success that year
was due to the inexperience of the male to
copulate with the much larger female, but things
changed dramatically in 2005 with the male
calling, passing food and scrape building, and
successful copulation resulted to the delight of
the falconers, who were again contemplating
artificial insemination. The season went well
with three eggs laid at two-day intervals from
the 19th February. Thirty-two days later the first
eyas was born, with a second the following day.
The third was dead in the egg and the fourth egg
was infertile. The two eyases (chicks) were left to
the parents to rear successfully.
Hacking is the process of reintroducing
captive bred birds back into the wild. Some
methods have been tried and tested by the Unit.
Initially the birds are placed in chambers at the
age of three to four weeks and are fed via a hole
Vincent Robba & Charles Perez
or trap door to avoid human contact. After seven
weeks they are brought out of the chambers and
are trained with traditional falconry methods
using a lure, until they are strong enough and
able to hunt for themselves, after which they
become accomplished hunters.
The Unit has also developed its own interesting
hacking method. This involves introducing
the young falcons to fly in the territory of the wild
Peregrines that have flying eyases themselves.
This is a risky business because if introduced at
the wrong time the wild Peregrines will attack
them, considering them intruders. By establishing
a synchronised breeding pattern with the wild
peregrines, the eyases are not attacked and the
captive birds are found to beg for food from the
wild adult Peregrines, which soon accept them as
their own young.
Up until 2011, twenty-four Peregrines had
been reared, of which fourteen had been successfully
reintroduced to the wild. This year only
one Peregrine has been successfully reared. Four
birds are still undergoing training and some of
these may be kept to establish other breeding
pairs. Six birds have been deemed not suitable or
fit enough for release and have been exchanged
for birds that will be more successful.
The Lesser Kestrels were first bred in 2011
and successfully fledged seven young in two successive
clutches of four and three birds. This year,
the captive birds reared a total of eleven birds,
of which seven have finally been released to the
wild, and three from the first clutch that are undergoing
training. The birds can be seen foraging
on Windmill Hill Flats, catching flying ants and
other ground invertebrates. They will soon depart
to the wintering grounds in Africa.
Peregrine Falcon
it recently, entitled “Ant identification boosts blue butterflies” (see: http://planetearth.nerc.ac.uk/
news/story.aspx?id=1176).
Apart from her PhD subject matter, Rhian Guillem has a strong interest in European and
Mediterranean ants and has published other papers about ants, some in conjunction with Dr Keith
Bensusan, also a GONHS Invertebrate Section member. She has so far recorded an incredible 51
species of ants from Gibraltar, including some that were new to Europe and one that she described
as new to science. Rhian’s valuable contribution to her area of expertise, and particularly using
taxonomic methods to aid in conservation issues, is an excellent example of the great work being
conducted by members of GONHS.
The full reference for the paper is:
Guillem RM, Drijfhout FP, Martin SJ. 2012. Using chemo-taxonomy of host ants to help conserve
the large blue butterfly. Biological Conservation. 148: 39-43. Published online 20 February
2012, http://dx.doi.org/10.1016/j.biocon.2012.01.066
TO JOIN... and support our work
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www.gonhs.org
NOTES
& NEWS
TURTLE SIGHTINGS
Sightings of turtles have become more frequent
this summer, with two seen on Eastern Beach,
at least five observed and photographed by
Nicholas Ferrary in the Strait and another two
observed on Europa Reef. Many others have
been reported by anglers. The Loggerhead
Turtle Caretta caretta probably accounts for
the majority of observations and sightings may
be linked to the increase in jellyfish, which
have been invading our shores and are a
source of food for turtles. Only last year two
anglers rescued a Loggerhead Turtle that had
got caught in a fishing net, highlighting the
grave threat that such nets pose to turtles and
other non-target marine life (see http://www.
gonhs.org/press.htm#Turtle).
UPPER ROCK NATURE
RESERVE ExTENDED
The boundary of the Upper Rock Nature
Reserve was extended in November 2011 to
include areas south of the Upper Rock including
Europa Foreshore, Jacob’s Ladder, Hole
in the Wall and many of the southern coastal
cliffs (see map). GONHS welcomes this and
hopes that the Government designates other
sites that are important to biodiversity but are
still not protected, or those that are designated
at a European Level but not as a local nature
reserve.
GIBRALTAR NATURE NEWS
11

GIBRALTAR NATURE NEWS
12
THE NATURAL HISTORY OF THE UK OVERSEAS TERRITORIES
7 Guernsey
Tidal Power in Guernsey
It is easy to be carried away with enthusiasm
for the generation of tidal power
in Guernsey waters. It seems so ‘right’!
Electricity generated from renewable resources
is considered one of the main ways that we
can reduce our dependency on fossil fuels.
Reliable sources suggest that more than half
of the world’s available oil resources have
already been used and that within the next 20
years oil is likely to become both scarce and
expensive. Alternative fuels will become more
costly. Having a secure and reliable source
of electricity generated from a renewable
resource would seem the obvious answer, particularly
for an island people. We have a timeless
supply of energy but there are challenges
to overcome before we can make use of it!
Tidal energy has been the subject of
considerable hype in recent years. The raw
energy of the tides is something that we can
all see but turning that power into usable electricity
will be expensive and is still some years
in the future. The potential is great but the
complex problems of exploiting the resource
are often overlooked. The devices that will
make it possible have not yet been proven and
in many cases are still on the drawing board.
Tidal energy will not be available in Guernsey
waters until 2015 at the earliest (when the first
devices might be installed) and there might be
benefits from delaying the deployment of a
full scale array (or tidal farm) until later when
equipment is available at a cheaper price due
to mass production.
That is not to suggest that renewable
Andrew Casebow
energy will not be important for the islands
in the future, but probably not as soon or as
cheaply as many people expect. In the words
of Alderney Renewable Energy Commissioner
Pamela Dixon, “We are playing a long game”.
The importance of off-shore renewable energy
from Channel Island waters may not be significant
for 20 years or more, but by then all energy
costs are likely to have risen significantly,
oil will be much more expensive and energy
produced from renewable sources will no longer
seem so expensive. It will be considered a
lifeline for the islands as a reliable and secure
source of home-produced energy that is not
dependent on expensive, imported fuel.
For the foreseeable future, electricity produced
from tidal energy will be more expensive
than conventionally generated electricity
and whilst the idea of exporting renewable
electricity to France or to Britain is attractive,
it will only become feasible if there is a cable
link to carry it. This will only be viable if the
feed-in tariff for renewable tidal electricity in
France is significantly greater than it is at the
present time, or that ‘green’ subsidies (in the
form of Renewable Obligation Certificates
– ROC’s) are available from Britain. To this
end, tidal energy from Guernsey might help
the UK to fulfil its renewable energy targets.
The recent ‘Marine Energy Plan’ published by
the British Government’s Department of Energy
and Climate Change notes that: Marine renewable
energy has a ‘small but significant’ part to
play towards the target of 15% of energy from
renewable resources by 2020: “It is possible
that marine energy will have a more significant
part to play in the period beyond 2030 and
will help to meet the policy of an 80% cut in
carbon emissions by 2050.”
Tidal electricity is likely to require a subsidy
to ‘kick-start’ the development but it has to
be guaranteed over the life of the equipment,
or for up to 25 years. In Scotland, to make
tidal energy viable, ROC’s effectively pay the
electricity generating companies a subsidy that
is about three times the cost of normal conventional
generation, whilst a French ‘feed-in’
tariff, which currently applies mainly to wind
energy, would need to value tidal energy much
more highly to make generation and export viable.
Therefore, whilst we might wish to export
the electricity produced, at present renewable
energy is likely to be mainly for island consumption.
The good news though is that the
island already has the infrastructure in place to
supply a limited amount of electricity to Jersey
and France through the existing cable link if, or
when, the price makes economic sense.
Tidal power is reliable because it is dependent
on the tides but, as a consequence, it is
intermittent (it is only generated when the tidal
stream is flowing). Therefore, even if most of
the electricity were produced by tidal generation
in the future there would still be a need for
other forms of generation at certain times in
the cycle. French electricity will still be needed
and given increasing demand it is likely that a
second cable, if only providing a back-up service,
will be needed. This could have the dual
role of supplying electricity at some stages of

the tide whilst receiving energy, perhaps from
wind power generated in Jersey waters or
French nuclear power.
Similarly, such a cable could conceivably
be linked through to Alderney, thereby
providing a channel islands ‘grid’, enabling
power generated in Alderney at certain periods
of the tide to be supplied to Guernsey or
Jersey, whilst power might be supplied back
to Alderney at other times. Hopefully, through
the newly formed Channel Islands Renewable
Energy Forum, the islands will be able to
‘speak with one voice’ to the French and
British governments, but equally, we now have
in place a group that can actively encourage
inter-island cooperation for our mutual benefit.
There are a number of social questions that
still need to be answered. Are we, as a community,
prepared to pay more for a proportion
of the electricity we use? We will have to one
day, but how soon? If we are prepared to pay
more, then how much more and how should
we pay for renewable electricity? Should we
pay for renewable energy as higher electricity
charges which would only disadvantage
electricity users and have an adverse effect on
local businesses, or should a carbon tax be collected
on all fuels sold that could then be used
to support local renewable energy generation
and higher standards of insulation? There are
some basic questions that need to be answered
and adequate provision made for disadvantaged
members of our community.
As a community in Guernsey we do need
to have a vision for the future that includes
renewable energy, but we need to consider
why we would wish to develop our ‘ocean
energy’ resources at this time.
We have a great resource, it’s nonpolluting
and the Guernsey Renewable Energy
Commission (GREC) is making good progress
in setting up a licensing regime that will ensure
that our precious environment is not damaged.
Richard Babbe, Chairman of the Commission,
explains the huge amount of work that has
been set in motion since the Commission was
set up in 2009: “We are in the process of
establishing a legislative framework, examining
the environmental and social issues, and
Guernsey Waters
ensuring that we are commercially attractive to
potential developers”. We have a basic dictum
in all our operations, that Guernsey should
be a good place for developers to do business!
There is an enormous amount of work
to undertake, in negotiating with the Crown
Estate that owns the seabed around Guernsey
(Alderney benefitted by owning the seabed
around the island), in preparing legislation, setting
up an appropriate and transparent licensing
and consenting regime, in undertaking a
Strategic Environmental Assessment of the area
(that has been called a Regional Environmental
Assessment locally as it takes into account just
Guernsey and Sark Territorial Waters), and
in attracting potential developers who wish to
develop the islands tidal resources.
Progress will largely be dependent on the
speed at which new devices can be developed
and mass-produced so that the electricity generated
can be commercially and socially viable,
in other words cheaper than if we develop
too soon! In the short term tidal energy will be
more expensive than conventional sources but
we will need to show some commitment if it is
to be available when energy becomes more
expensive or less easy to obtain in the future.
What does Guernsey want from renewable
energy? Is it economic development, a more
diversified economy, energy security, or a
chance to earn money from the future export of
energy? Or is it that we wish to be ‘green’ and
fulfil our international obligations to reduce
carbon emissions by using tidal energy? It is
important that we understand what we want to
achieve before we start or we are bound to be
disappointed.
The development of renewable tidal energy
is a long and complex road and, as so
often the case, it will not be the community that
develops tidal energy first that will be most successful,
but the one that develops it for the right
reasons, using the most efficient equipment
and at the right time – both technically and
economically – that will achieve the best result.
It is not a race, but as in Aesop’s fable of the
Hare and the Tortoise, it will be the Tortoise
that proceeds at a slow and steady pace, that
will win the prize!
NOTES
& NEWS
WEDDING ANNIVERSARY
This summer sees the first wedding anniversary
of Ian Thompson and Yvonne Benting, both
GONHS members and regular visitors to the
Jews’ Gate Observatory, where they have
been visiting ringers for many years. Ian and
Yvonne in fact met in Gibraltar whilst ringing
at Jews’ Gate and they thought it would be
apt to tie the knot in the Gibraltar Botanic
Gardens. GONHS wishes Ian and Yvonne
every happiness in their lives together and
hope that they will continue to visit Gibraltar,
where they will always be welcome, on a
regular basis.
Ian & Yvonne trapped in 2008,
ringed in 2011.
METCALFA
Gibraltar has recently experienced an invasion
of the Citrus Planthopper Metcalfa pruinosa
(see photo below). This North American
bug originally arrived in Italy but has spread
throughout the Mediterranean. Specimens
from Gibraltar were identified by Dr Mike
Wilson from the National Museum of Wales,
Cardiff, who recently became a GONHS member.
Metcalfa is a sap feeder and the fluffy,
immature stages can be noticeable on plants.
Adults too can be quite prominent, especially
when they are attracted into people’s homes
at night by bright lights. Control methods
are currently being investigated. A full report
can be found at www.gibraltargardens.gi/
documents/Metcalfa.pdf
MORE HOPPERS
Another exotic hopper recently found in
Gibraltar was the Asian Sophonia orientalis,
which like Metcalfa was first detected with a
light trap that is run at the Gibraltar Botanic
Gardens on a nightly basis. This was in fact
the first record for mainland Europe and
was published as such. Unlike Metcalfa,
Sophonia has so far been found not to be
numerous. Citation: Wilson, M., Bensusan,
K., Perez, C. & Torres, J.L. 2011. First
records of the exotic leafhopper Sophonia
orientalis (Matsumura, 1912) (Hemiptera:
Auchenorrhyncha: Cicadellidae) for the
Iberian Peninsula and mainland Europe.
Boletin Sociedad Entomologica Aragonesa,
48: 435-436.
GIBRALTAR NATURE NEWS
13

GIBRALTAR NATURE NEWS
14
6
NATURAL HISTORY AND ART:
WHAT ABOUT GRAFFITI?
Those of you who know me will be aware
that I collect natural history objects, books,
photos and documents, and many other things
besides. It will come as no surprise, therefore,
that over a number of years I have built up a collection
of photos of graffiti I have seen around
Gibraltar, more particularly graffiti that have a
natural history flavour. I started my collection
when I discovered a small graffito on a wall in
my garden of a snail that my son, Alex, had
painted clandestinely (photo 1).
Although we mostly use the term graffiti
when talking about one or more items, ‘graffito’,
although rarely used, is the singular of ‘graffiti’.
The word derives from the Greek ‘Graphein’
which means ‘to write’. This in itself gives a clue
as to what most authors on the subject agree on,
namely that graffiti is the act of drawing or writing
on walls or other surfaces in order to communicate
messages to the public. There is an
enormous literature on whether graffiti is art or
crime. Many argue that graffiti has been a part
of human culture since the drawing of the first
pictures in caves. I suspect, as a layman, that the
Alex Menez
way most people might decide whether graffiti
is art or crime centres mainly on location. If a
graffito is somewhere ‘acceptable’, perhaps the
side of a building where it may be obvious it
has been commissioned, it is art; if, on the other
hand someone has created a piece on a wall in
an underground railway station or on the side
of a shop, it is ‘defacing’ and thus seen as a
crime. In addition, graffiti that are pleasing to
the eye are much more likely to appeal to the
viewer than items that consist of letters or words
only, wherever they are located.
There are different types of graffiti and
these are categorized according to complexity
and difficulty. First is the ‘Tag’ which is
the simplest type (normally just showing the
artist’s name in one colour). Next is the ‘Throwup’
that generally has two or three colours.
‘Wildstyle’ uses spikes, arrows, curves and
other effects to create mostly 3D images that
are very complex. Other categories include
‘Masterpiece’, a complex painting with several
colours; ‘Blockbuster’ where an area is painted
in the minimal amount of time, and ‘Heaven’
1 2 3 4
where graffiti is created on the tops of tall
buildings or other hard to reach places. There
is even custom software available for graffiti
analysis that allows writers to share analytical
representations of their hand styles. There are
acceptable ways of working and un-written
codes of conduct for graffiti artists. For example
it is considered extremely disrespectful if a ‘Tag’
is put up over another writer’s tag or piece.
And graffiti artists who manage to produce a
‘Heaven’ gain respect from their peers because
of the danger involved.
Other types of graffiti include ‘Stickers’
that allow detailed creations to be done at
home then stuck wherever the artist decides,
and ‘Stencils’ which allow the production of
complex pieces to be done quickly. The stencil
is held against the wall and sprayed. This type
of graffiti was made popular by Banksy, who
some have described as the most famous, or
infamous, artist alive and who some consider a
genius and others a vandal. Banksy has added
mystery and intrigue to the world of the graffiti
artist: his identity remains a mystery, as does

7 8 9 11
the way he is able to produce his work without
being detected doing it. And an element of this
mystery has now reached Gibraltar.
Three Gibraltar Chronicle articles have
reported on graffiti that have a Banksyian
resemblance. The first (11th May 2011 edition)
included a photo of the graffito of a monkey
with a crown, looking a little like Banksy’s
famous ‘Monkey Queen’. The second (22nd
June 2011 edition) and third (29th June 2011
edition) reported on new graffiti that have
appeared since the first article was published.
The first graffito that started off the search
for further examples appeared on a wall of the
Market Square (photo 2) during the first week
of May 2011. Although resembling Banksy’s
‘Monkey Queen’ there is a significant difference
in that the ‘Monkey Queen’ depicts a chimpanzee,
whereas the ‘Market Queen’ depicts what
is possiblly a homegrown Gibraltar monkey.
And whilst it’s possible Banksy may have
popped over to Gibraltar for a visit and
adapted his original graffito to suit the local
primate scene, it’s much more likely that, as
the Chronicle has suggested, there may be
a Banksy mimic in Gibraltar (who has been
dubbed Llanksy by a fan).
Within a few days of the appearance of the
‘Market Queen’ several other stencilled monkey
graffiti appeared. Examples include one at the
entrance of the Upper Rock Nature Reserve
(photo 3) looking decidedly more masculine, as
Photographs:
Photo 1: This snail, painted on my garden wall
several years ago by my son, started my interest
in graffiti.
Photo 2: The ‘Market Queen’ appeared on a
wall at Market Square in May of 2011.
Photo 3: A revolutionary monkey on a wall at
the entrance to the Upper Rock Nature Reserve.
Photo 4: This graffito from Ocean Heights
closely resembles the ‘Market Queen’.
Photo 5: A multiple stencil rendition at the Old
Police Barracks.
Photo 6: ‘Graffiti Wall’ at the Northern
Defences (‘The Jungle’). Note the use of a
human skull theme.
Photo 7: Detail from ‘Graffiti Wall’: A snail.
Photo 8: Detail from ‘Graffiti Wall’: A spider.
5
well as revolutionary, than the one at the market;
and another on a wall by Ocean Heights
that closely resembles the ‘Market Queen’ (and
may be produced from the same stencil) (photo
4). Others have appeared: a multiple rendition
of four stencils on hoarding at the Old Police
Barracks (photo 5), the Alameda and Landport
Tunnel.
The resemblance of the ‘Market Queen’
to a Banksy production started the recent interest
in graffiti locally, after all everyone loves
a mystery. But there exist graffiti of a natural
history flavour that pre-date this. Some of my
favourite graffiti are on a wall outside the north
entrance of the Prince’s Gallery tunnel at the
Northern Defences (colloquially called ‘The
Jungle’). While it may be difficult to put oneself
into the mind of the artist(s) responsible, the
mix of species used and incorporation of skulls
into the designs, along with the bright colours,
provide an unusual (and possibly psychedelic)
effect (photos 6-12). There is also a graffito on
a wall in Fishmarket Lane that I call the ‘Angry
Mushroom’ (photo 13).
Perhaps our current local mystery graffiti
artist (if indeed it is just one person) will, like
Banksy, never be identified. I have a suspicion
as to who it might be, however. A recent art
exhibition included a piece that incorporated,
as a part of the entire work, an image that
looked (at least to my completely non-qualified
eye) decidedly like the ‘Market Queen’!
Photo 9: Detail from ‘Graffiti Wall’: A
ladybird.
Photo 10: Detail from ‘Graffiti Wall’: This,
the main component of the ‘piece’, centralizes
the human skull theme used in the
paintings, as well as portraying a Gibraltar
theme (note the Castle and Key). The
multiple names surrounding the skull suggest
that at least three artists contributed
to the ‘piece’.
Photo 11: Detail from ‘Graffiti Wall’: A
colourful moth that incorporates the skull
theme looks very much like a psychedelic
Death’s Head Hawkmoth.
Photo 12: Detail from ‘Graffiti Wall’: An
Octopus that cleverly incorporates the skull
theme in its design.
Photo 13: The Angry Mushroom of
Fishmarket Lane.
10
12
13
GIBRALTAR NATURE NEWS
15

GIBRALTAR NATURE NEWS
16
Mantisalca salmantica
Trifolium subterraneum, Astragalus pelecinus,
Long-beak Storksbill Erodium botrys and
Warty Scorpiurus Scorpiurus vermiculatus.
The fauna of the flats is as varied as the
flora. This is due to habitat structure and
diversity, geographical location and a relative
lack of disturbance compared with other
habitats on the Rock. The site is famous as a
stopover point for migrating passerines and
numbers can often be impressive. Passerine
migrants that stand out are species of open
ground and scrub such as Northern and
Black-eared Wheatears Oenanthe oenanthe
& O. hispanica, Whinchats Saxicola rubetra,
Subalpine and Spectacled Warblers Sylvia
cantillans & S. conspicillata, Whitethroat
Sylvia communis, Tawny Pipit Anthus campestris
and Yellow Wagtails Motacilla flava.
Its prominence geographically helps to attract
many vagrants. Indeed, many of the species
mentioned in this issue’s ‘Birding Scene’ were
Salvia verbenaca Ophrys apifera
recorded at Windmill Hill. More unusual
but regular species include Stone Curlew
Burhinus oedicnemus and Short-eared Owl
Asio flammeus. Windmill Hill hosts occasional
breeding Zitting Cisticolas Cisticola juncidis
and has traditionally been the stronghold
of the Barbary Partridge Alectoris barbara,
although this species has recently experienced
a severe decline as a result of Feral Cats.
Other characteristic residents include Blue
Rock Thrush Monticola solitarius and Spotless
Starling Sturnus unicolor.
Windmill Hill is
also an important wintering
site for Meadow
Pipits Anthus pratensis,
Black Redstarts
Phoenicurus ochruros,
Oestophora calpeana
European Stonechats
Saxicola rubicola, finches and the occasional
Thekla Lark Galerida theklae and Skylark
Alauda arvensis, the only site in Gibraltar
where larks are reliably recorded.
As may be expected of open, sunny
habitats, reptiles thrive on Windmill Hill Flats.
Some of the most recent records of Ocellated
Lizard Timon lepidus in Gibraltar have been
from Windmill Hill. Large Horseshoe Whip
Snakes Coluber hippocrepis, Montpellier
Snakes Malpolon monspessulanus and
Ladder Snakes Elaphe scalaris weave
through the vegetation looking for their prey.
Although Gibraltar has a poor mammalian
fauna, Windmill Hill is the stronghold of the
European Rabbit Oryctolagus cuniculus on
the Rock. Their scrapings can be conspicu-
Northern Wheateter
ous during the summer, when they forage for
moist roots and bulbs.
Windmill Hill Flats is one of Gibraltar’s
premier sites for invertebrates due to its floral
diversity. In fact the sun-bathed, rocky and
flowery habitats of the southern end of the
Rock, including those around Camp and Little
Bay, Europa Point and Europa Advance Road
are generally rich in phytophagous invertebrates;
much more so than large, maquiscovered
swathes of the Upper Rock. Beetles
that develop within flowering plants abound
at Windmill Hill. Likewise, nectar-rich flowers
are teaming with hoverflies and bees during
the spring.
Species lists are extensive and ever growing.
Windmill Hills’ high habitat diversity
affords structural diversity at small scales,
making the site ideal for land molluscs.
Almost half of Gibraltar’s species have been
recorded, making it a local biodiversity
‘hotspot’. It is an important site for smaller
species including Acicula norrisi, Vallonia
pulchella, Truncatellina cylindrica, Cecilioides
acicula, C. petitiana, Xerotrichia conspurcata,
X. apicina and Microxeromagna armillata.
Other species include Rumina decollata,
Parmacella valencieni, Caracollina lenticula,
the Gibraltarian Snail Oestophora calpeana,
Otala lactea and Cornu aspersum.
The beetle, ant and fly faunas are also
rich and include species with specialised
life-histories. For example, the attractive leaf
beetle Tituboea biguttata feeds on the leaves
Tomares ballus
of Lentisc as an adult. However, its life-cycle
is complex and the species relies on the
harvester ant Messor barbarus, with larvae
living within the ants’ nests. Since Windmill
Hill Flats is the only site in Gibraltar where
Lentisc and Messor barbarus are present
together in good numbers, it is the only site
where this interesting beetle can be found.
Alternatively, those who stand still and
watch Bembix digger wasps coming back
and forth from their burrows may notice
these being trailed by small Satellite Flies
(Sarcophagidae: Miltogramminae), which
are brood parasites of these wasps, much
like cuckoos have their young reared by
other species of birds.
Butterflies are another feature of
Windmill Hill. It is the local stronghold
of the Provence Hairstreak Tomares ballus,
Southern Brown Argus Aricia cramera
and Green-striped White Euchloe belemia.
Swallowtails Papilio machaon float over the
vegetation, their healthy population sustained
by the abundance of their food plant, Bitter
Fennel Foeniculum vulgare subsp. piperitum.
Perhaps most impressive are the migrations of
Painted Ladies Vanessa cardui, often numbering
many hundreds. So important is Windmill
Hill for migrating Painted Ladies that it was
recently selected as a study site for research
into orientation of migrating butterflies. These
migrations sometimes coincide with those of
dragonflies, especially the numerous Redveined
Darter Sympetrum fonscolombii.
Windmill Hill, then, is undoubtedly a
prime refuge for Gibraltar’s rich biodiversity.
Only adequate, sustained protection and sensitive
management will ensure the continued
importance of this local gem of a habitat for
native flora and fauna.
Filago pygmaea