Alcyon Project: Protecting seabird and marine IBAs in West Africa

2 nd World Seabird Conference
“Seabirds: Global Ocean Sentinels”
26-30 October 2015 Cape Town, South Africa
FEEDING ECOLOGY OF THE CAPE VERDEAN SHEARWATER
(Calonectris edwardsii) POPULATION OF RASO ISLET, CAPE VERDE (P1-B-11)!
Isabel Rodrigues 1,3; Nuno Oliveira 2 Rui Freitas 3 Tommy Melo 1 Pedro Geraldes 2
1
Biosfera I, Cabo Verde, www.biosfera1.com; 2 SPEA, Portugal, www.spea.pt, 3 Universidade de Cabo Verde, www.unicv.edu.cv
Raso Islet with only 5.76 km 2 , is an area of great importance to Cape Verdean Shearwaters as we find one of the largest colonies of the species there.
The great biological value of this islet is even more remarkable for hosting very large populations of other species, such as the Brown Booby, Red-billed Tropicalbird and even
the endemic Raso Lark, among others. Along with Branco Islet, also included in the Nature Reserve, both populations constitute about 75% of the nesting population of the
Cape Verde islands (Fig. 1).
The Cape Verde Shearwater (Procellariiformes, Procellariidae) (Fig. 2) is an endemic species of Cape Verde and has recently been separated from Calonectris diomedea
species, due to their morphological and genetic differences, and pelagic habits; feeding mostly on the open sea (Hazevoet 1995).
METHODOLOGY
RESULTS
The samples were collected between 14 October and 12 November, in two
consecutive years, 2012 and 2013. We randomly obtained 80 samples of juvenile
regurgitation. Each juvenile was sampled only once. During or after handling,
juveniles tend to regurgitate stomach contents without the need to resort to the
induced regurgitation method.
Juveniles are fed by the parents during the night and the capture and monitoring of
birds was made during the early morning hours.
After collection, the individuals were marked with a numbered metal ring in its right
leg, and the number of nest where they were captured was recorded, avoiding
duplication of sampling and reducing the disturbance of the same individual.
In total, 80 regurgitations from juvenile Cape Verde Shearwaters were collected;
including 50 individuals sampled in 2012, and 30 individuals in 2013.
Based on knowledge of local fish populations and according to the current
description, the identified prey of Cape Verde shearwaters belonged to 5 species
distributed in 4 different families (Platybelone argalus lovii - Belonidae, Selar
crumenophthalmus, Decapterus sp – Carangidae; Sardinella maderensis –
Clupeidae; Loligo sp. - Loliginidae).
In 2012, the Horse-Eye Jack (Selar crumenophthalmus) was the most frequently
occurring prey (38%); identified in 21 samples, whereas in 2013 this species was
replaced by the Sardine Sardinella maderensis (61%); represented by 25 samples
(Fig. 3 & 4).
During the monitoring, it was noted that as time progressed, weight increased, but
then began to fall; stabilizing, while the length of the wing increased (Fig. 5 & 6).
CMYK - blue to green
5%
27%
0%2%
Frequency of occurrence (%)
37%
29%
Sardinella maderensis
Selar crumenophthalmus
Platybelone argalus lovi
Loligo sp.
Decapterus sp.
Not Identif.
Fig. 3 Frequency of occurrence (%) of prey
found in Shearwater regurgitations , Raso Islet
in 2012.
32%
5% 2%
Frequency of occurrence (%)
61%
Sardinella
maderensis
Loligo sp.
Decapterus sp.
Not Identif.
Fig. 4 Frequency of occurrence (%) of
prey , found in Shearwater
regurgitations, Raso Islet in 2013.
A
Fig. 1 Map of the Cape Verde islands, with location of the study area,
Raso Islet - Cape Verde
B
C
Fig. 2: A - Juvenile Cape Verde Shearwater, B,C- Capture of Shearwater in Raso, Cape Verde.
Fig. 5: Evolution of average weight
during the period of Shearwaters chick
monitoring in Raso Islet in 2013.
Fig. 6: Change in average wing length
during Shearwater juvenile
development in Raso Islet in 2013.
DISCUSSION
The results showed that the diet of Cape Verde Shearwater is mostly rich in organisms of Superclass fish, and it may be related to the fact that they are more nutritional and energetic than
Mollusca (Ainley et al., 2003). Cephalopods of Loliginidae, were not fully identified to species level, since the food capture process sometimes has difficulties in identifying and quantifying
food items, which may cause some bias in the results (Duffy & Jackson, 1986).
The species that stood out in the diet of Cape Verde Shearwater in 2012 was the Horse-Eye Jack, with 38%. The spawning period of this species occurs mainly between October and
December, coinciding with the time of sampling, which may correspond to a greater availability of this prey. However, in 2013, sardines represented 61% of chicks diet, suggesting that the
Cape Verde shearwater changes diet according to food availability. There were no important differences in the interpretation of analyzes of the frequency of occurrence and number, which
was fairly expected because, according to Zavala-Camin (1996), numerical frequency is a direct consequence of occurrence, as it is only possible to count what was identified.
Despite the reduced frequency of occurrence and number, the high energy of the cells indicates a greater role of these organisms in feeding the shearwater chicks. With regard to biometric
data, the data obtained was expected, this is because Cape Verde shearwater chicks have a much higher weight in the early stages of development, but as they grow they begin to lose
weight until they are able to fly.
Bibliography:
AINLEY, D., BALLARD, G., BARTON, K., KARL, B., RAU, G., RIBIC, C., WILSON, P. 2003. Spatial and temporal variation of the Adélie penguins. The
Condor, 105: 95–106 pp;
HAZEVOET, C.J. (1995). The Birds of the Cape Verde Islands. British Ornithologists’ Union. B.O.U. Check-list nº13. 192 ;
DUFFY, D. E JACKSON, S. (1986). Diet studies of seabirds: a review of methods. Colonial Waterbirds 9: 1-17; ZAVALA-CAMIN, L.A. (1996).
Introduction studies on natural food in Peixes.Maringá, EDUEM, Maringa. 129P.
With the financial support of MAVA Foundation

2 nd World Seabird Conference
“Seabirds: Global Ocean Sentinels”
26-30 October 2015 Cape Town, South Africa
ANALYSIS OF MONITORING METHODS OF SEABIRD COMMUNITIES
ON RASO ISLET, CAPE VERDE (P2-H-173)
Almeida, Nathalie 1 ; Paiva, Vitor 2 ; Ramos, Jaime 2 ; Geraldes, Pedro 3 ; Fortes ,Isabel 1 ; Melo, Tommy 1 ; Rabaça, João 4
1
Biosfera I, Cape Verde, www.biosfera1.com; 2 Coimbra University; 3 SPEA, Portugal, www.spea.pt; 4 Évora University
Raso Islet is an authentic sanctuary for seabirds; some of them endemic to Cape Verde. In this present work we studied the populations of pelagic seabirds (Procelariiforms) of Calonectris
edwardsii (Oustalet, 1883) Cape Verde Shearwaters and Bulwer’s Petrel Bulweria bulwerii, (Jardine & Selby, 1828) from the islet. The current size of the shearwater population is not very well
known, as well as the impact of continuous illegal killing of juveniles. Given that the majority of the world population of this species is in Santa Luzia and Branco and Raso Islets MPA, it is
essential to know the size of the breeding population (Lecoq, 2009), as well as the Bulwer’s Petrel population since we found no literature related to recent census for the Cape Verde islands.
Cape Verde Shearwater
Fig. 1 – Geographic location of Raso Islet.
Bulwer’s Petrel
From August - November, we used a series of fixed-point circular plots (total plot area = 706.50 m 2 )
counting holes with chicks/parents/eggs of the target species. The islet (Fig. 1) was then mapped
and divided into UTM squares, where 28 plots were randomly distributed in representative areas of
the colonies (Fig. 2) predicting nest densities for a combination of environmental variables
described, through multiple regression, and then resorted to extrapolation with the colony area to
obtain a population estimate and compare with other data from previous studies.
In 209 detections of active nests in 2013 (Fig. 3), we obtained NLLR and PVEG as the most
significant characteristics (Table 1) for predicting densities of B. bulwerii, as it breeds more in coastal
ravines and rocky walls in the islet interior, and in areas where there is presence of vegetation,
functioning as cover for the rocks and cavities where they occur. For C. edwardsii, PVEG is most
important and significant (Table 2); acting as a form of protection against nest floods, reducing their
impact and preventing rock landslides, causing chick mortality.
20
15
Nº of nests
10
5
CMYK - blue to green
0
P1
P2
P3
P4
P5
P6
P7
P8
P9
P10
P11
P12
P13
P14
P15
P16
P17
P18
P19
P20
P21
P22
P23
P24
P25
P26
P27
P28
Nº of Plots
Fig. 3 Number of Calonectris edwardsii (Green) and Bulweria bulwerii (blue) nests for each plot.
Fig. 2 –Calonectris edwardsii) ; unoccupied areas (brown) ;colonies (yellow) 28 plots (green).
Source: Lecoq, 2009
Coefficients!
Statistics!
Final
Model! !
SE!
T! P!
Constant! -0,041! 0,020! -2,066! 0,049!
VEGP! 0,026! 0,008! 3,172! 0,004!
NLLR! 0,020! 0,009! 2,102! 0,046!
Table 1 – Coefficients and statistics of selected
parameter in the final explaining model of the
density of Bulweria bulwerii. VEGP –
Vegetation Percentage. NLLR – Number of
Large Loose Rocks.
Coefficients
Statistics
Final Model ! SE T P
Constant 0,060 0,023 6,326

2 nd World Seabird Conference
“Seabirds: Global Ocean Sentinels”
P1-B-16
26-30 October 2015 Cape Town, South Africa
ANALYSIS OF CHICK CONDITION OF CASPIAN TERNS COLONY
BREEDING IN THE SALOUM DELTA NATIONAL PARK, SENEGAL
Stanislas MALOU, stanislas.malou@yahoo.fr
MSc. student , Ecology and Ecosystem Managment, University Cheikh Anta Diopof Dakar, Senegal
Animal Biology Department
Cheikh Anta Diop University of
Dakar, Senegal (UCAD)
Linking structural parameters of growth-to-body mass of seabird chicks is a way to assess body condition. Condition is a sensitive measure for prey availability and can be used to assess the influence of
environmental factors (fisheries, weather, SST, etc.). Several methods to calculate condition have been used in Saloum Delta NP, Senegal, since 1998 (Veen et al. (2003), Klaassen (2008) and Lubbe et al. (2014),
but each method has advantages and drawbacks. The current study uses Caspian Terns Hydroprogne caspia as a model species to compare these three (3) different methods, and suggests which method should
be used for calculating body condition for long-term monitoring.
The methods compared and Results
From 1998 till 2015, head + bill length (mm) and body mass (g) of Caspian Tern chicks of all ages were measured in Saloum Delta National Park, Senegal, by using Vernier callipers and electronic weighing scales.
The data was subsequently analyzed by applying the three (3) different methods as proposed by Veen et al. (2003) 1 , Klaassen (2008) 2 and Lubbe et al. (2014) 3 .
The Veen method use the similar growth logistic model: y = A/(1+exp(-K*(x-T))). A, K, T are parameters that need to be estimated. It is the relation between body mass (y) and bill+head (x). However, this growth
logistic model corresponds to the maximal growth line (100%) and the lower growth line corresponds to 48% of the maximal.
The Klaassen method considers mass dependent on structural measures. For the relation between body mass (M) and bill+head (H), it assumed a growth logistic model: M = A/(1+bexp[-kH], where A, b, k are
parameters that need be estimated. Thus, for each individual a mass index was calculated using: -ln(A/M-1), which, according to the logistic growth model, should yield a straight increasing line with bill+head.
The Lubbe method use the quantile regression technique. Quantile regression is a method for estimating functional relationships betwen variables for all portions of a probability distribution. Quantiles 0.02 and
0.98 are chosen to estimate the lower and upper line respectively.
Figure 2 (Klaassen method) shows a highly significant relationship between mass-index and bill head. This relationship also appears to be linear regression. The same observation appeared in Figure 3 (Lubbe
method) but Figure 1 (Veen method) shows non-linear regression. The Klaassen and the Veen methods allow all data to be used. The Klaassen method cannot show good and the bad chick condition but the
Veen method evaluates both good and bad chick condition. Indeed, this method shows the upper line (100%), which corresponds to good chick condition, and the lower line (48%) corresponding to bad chick
condition but the main disadvantage of Veen’s approach is the fitting of an upper line by eye. Veen et al. (2003) considered the lower limit of growth to be 48% of the maximal growth line (Lubbe et al., 2014).
CMYK - blue to green
However, the Lubbe method uses the quantile regression technique to fit the equivalent Veen et al.’s (2003) maximal growth line. This method is statistically based: Heteroscedasticity test or Breusch-Pagan/Cook-
Weisberg test (chi2 = 23.59, p-value = 0.0000). This test shows the quantile regression technique is the best way to evaluate chick condition. The main disadvantage of this approach depends on the rigour of its
study; the choice of extreme quantiles is different.
Scatterplot of Mass Index against BillHead; categorized by year
Condition chicks 1998-2007 all data MK 17v*1748c
800
1
Include condition: v3="CT"
5
700
0,48
600
1998
1999
4
3
Weight (g)
500
400
300
2000
2001
2003
2004
Mass Index
2
1
0
200
100
0
40 50 60 70 80 90 100 110 120
2005
2011
2012
2013
2014
-1
-2
-3
-4
40 60 80 100 120 140
year: 1998
year: 1999
year: 2000
year: 2001
year: 2003
year: 2004
year: 2005
year: 2006
BillHead (mm)
BillHead
Figure 1 : Chick condition of Caspian Terns (Veen method) Figure 2 : Chick condition of Caspian Terns (Klaassen method) Figure 3 : Chick condition of Caspian Terns (Lubbe method)
The quantile regression technique (Lubbe method) seems to be the best way to estimate chick condition. It is important to explore more methods, before a final conclusion.
1
Veen, J., Peeters, J., leopold, M. P., Van Damme, C. J. G. & Veen, T. 2003. Les oiseaux piscivores comme indicateurs de la qualité de l’environnement marin: suivi des effets de la pêche littorale en Afrique du Nord-Ouest. Alterra-rapport 666, ISSN 1566-7197, 190p.
2
Klaassen, M. An analysis of the condition of the chicks of West African colony breeding birds: data on terns and gulls from Senegal collected in the period 1998-2006. Unpublished.
3
Lubbe, A., UnderhillL, G., Waller, L. J. & Veen, J. 2014. A condition index for African penguin Spheniscus demersus chicks. African Journal of Marine Science, University of Cape Town Libraries: Taylor & Francis. ISSN 1814-232X. 12p.
Acknowledgements
This research was based on collaboration between Cheikh Anta Diop University and the Alcyon Project, funded by the MAVA Foundation and coordinated by FIBA until
December 2014, and BirdLife International (from January 2015 onwards). We thank both institutions for granting us internships at PNDS. Thanks are also due to Jan Veen &
Wim C. Mullié for providing the body condition data collected from 1998 to 2014.
With the financial support of MAVA Foundation

2 nd World Seabird Conference
“Seabirds: Global Ocean Sentinels”
P1-B-26
26-30 October 2015 Cape Town, South Africa
FOOD ECOLOGY OF CASPIAN TERNS DURING THE NESTING PERIOD
IN THE NATIONAL PARK OF SALOUM DELTA, SENEGAL
Sokhna Momie THIAW, sokhnamomie@gmail.com
MSc. Student, Ecology and Ecosystem Management, University Cheikh Anta Diop of Dakar, Senegal
Animal Biology Department
University Cheikh Anta Diop of
Dakar, Senegal (UCAD)
The Canary Current upwelling system along the West-African coast (Bellemans, 1988) is extremely rich in fish which attracts piscivorous colonial seabirds. These birds breed on islands from Mauritania in the north to Guinea
in the south. The Delta Saloum in Senegal; a wetland of international importance (Dia, 2003), harbours important colonies of Sternidae and Laridae. Three (3) species, Royal and Caspian Term, & Slender-billed Gull) were
chosen as indicators in a long-term monitoring programme (started in 1998) to obtain information about prey-availability and related environmental factors in the West-African marine environment (Veen et al. 2003, Mullié et
al. this conference). The current study deals with the feeding ecology of the Caspian Tern (Hydroprogne caspia; further CT) in Saloum Delta National Park, Senegal, for two months from April - June 2014.
An enclosure around 13
nests was used to assess
food provisioning of chicks
by direct observations. The
length of the prey was
estimated by comparison
with Caspian Tern bill
length. Observations were
made from 7 am to 7 pm.
Faeces and regurgitated
pellets were collected to
identify the fish otoliths
they contained. Three (3)
Caspian Tern breeding
next to the enclosure
were equipped with UVA-
BiTS data loggers.
Individual! Period! beginning! End! Distance in
km!
Abdou
logger
2075!
Moussa
logger
2062!
Nicolas
logger
2063!
Incubation! 05/05/2014
!
Chick
Rearing
!
17/05/2014
!
Incubation! 27/04/2014
!
Chick
Rearing
!
Incubation
!
Chick
Rearing
!
16/05/2014
!
27/04/2014
!
13/05/2014
!
16/05/
2014
!
27/05/
2014
!
15/05/
2014!
27/05/
2014
!
09/05/
2014
!
19/05/
2014
!
73 ± 14,8
(14,5-174)
!
39 ± 4
(0,13 - 99)
!
83,6± 48
(26 – 183)
!
42,2 ± 4,8
(14– 11)!
90 ± 18
(0,3-170)
!
46 ± 4
(12-108)
!
Duration of
out H!
4:01± 0:49
(0:37-8:41) !
1 :27±0:08
(0:36-3:53)!
4:34±0:51
(1:149:32)!
2:18±0:17
(0:34-6:26)
!
4:28± 0:46
(1:33-8:00)
!
1:35 ± 0:07
(0:42-3:31)
!
Distance
colony!
34 ± 21
(10 – 63)!
15 ± 13
(3 – 54)!
27 ± 10
(13 - 42)!
12 ± 7
(1 - 25)!
40 ± 25
(12–102)!
16 ± 11
(4 – 53)!
Duration of
food!
2:33 ± 2:01
(0:08 - 1:27)!
0:35 ± 0:25
(0:08- 6:00)!
2:46 ± 2 :00
(0:35- 6:26)!
1:12 ± 1:01
(0:08- 4 :49)!
2:34 ± 1:34
(0 :04 - 0:59)!
0:23 ± 0:17
(0 :44 - 5 :11)!
N!
N/J!
14! 1!
30! 3!
10! 1!
20! 3!
9! 1!
23! 3!
Number of prey
Frequency distribution of prey brought to the chicks
45
40
35
Frequency of prey in %
30
25
20
15
10
5
CMYK - blue to green
0
0 to 5 5 to 10 10 to 15 15 to 20 20 to 25 25 to 30
Size of the preys in cm
Foraging distances during
the incubation and chick
rearing period.
Foraging durations
during the incubation and
chick rearing period
Prey composition (fish families) in pellets of Caspian Terns, collected
in the experimental enclosure during the breeding saison
Based on the otoliths recovered, the Caspian Tern in the enclosure preyed upon 24 fish species.
The average size of prey fed to the chicks increased from 1 to 30 cm.
Incubating birds made fewer, but longer foraging trips (N= 1/day, avg. distance 50 to 100 km) than
birds with chicks (N=3/day, avg. distance 4 to 18 km).
Birds showed a peak in foraging activities in the morning and a less pronounced peak at the end of
the afternoon
References
Caspian Terns proved to be an excellent model species as they were quite insensitive to handling and
disturbance in the enclosure and allowed observations at close range. Direct observations of food
provisioning of the chicks in combination with the analysis of faeces and pellets (Veen et al. 2002)
provided quite an unbiased measure of their diet etc.
The use of miniaturized data-loggers provided a wealth of information on home ranges and feeding
areas, allowing us to calculate the size of home ranges; water depths included in their feeding ranges;
distances covered; and maximum time and distance from the nest without time-intensive observations.
M. Bellemans, A. Sagna, W. Fischer et N. Scialabba, 1988, fiche FAO d’identification des espèces pour les besoins de la pêche, guide des ressources halieutiques
du Sénégal et de la Gambie (espèces marines et d’eaux saumâtres), 227p.
Dia.I.M(2003). Elaboration et mise en œuvre d’un plan de gestion intégrée : La Reserve de Biosphere du Delta du Saloum, 130p.
Morel, G, Roux. F (1974). Les migrateurs paléarctiques. Extrait de la Terre et la Vie, Revue d’Ecologie Appliquée Volume 27, 1973 : p. 523-550.
Veen, J., Peeters, J., Leopold, M.F., Van Damme, C.J.G. & Veen, T. 2003. Les oiseaux piscivores comme indicateurs de la qualité de l’environnement marin: suivi
des effets de la pêche littorale en Afrique du Nord-Ouest. Alterra report 666: 1-190.
Acknowledgements
This study was financed by the MAVA foundation in the frame of the Alcyon Project. Justine Dossa, Wim
Mullié, Jan Veen, Ibnou NDIAYE & Cheikh Tidiane gave helpful orgnizational and scientific support. Also
Stanislas MALOU my partner in this research. Thanks are due to all of them.
Locations where foraging activities of three birds with
GPS data-loggers were concentrated
With the financial support of MAVA Foundation

2 nd World Seabird Conference
“Seabirds: Global Ocean Sentinels”
26-30 October 2015 Cape Town, South Africa
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2 nd World Seabird Conference
“Seabirds: Global Ocean Sentinels”
26-30 October 2015 Cape Town, South Africa
ABUNDANCE, BREEDING PHENOLOGY AND SUCCESS OF THE RED-BILLED TROPICBIRD
(Phaethon aethereus) IN MADELEINE ISLAND (DAKAR, SENEGAL)
Ngoné Diop 1 2 Cheikh Tidiane Ba 1 Papa Ibnou Ndiaye 1 Jacob González-Solís 2
1. Department of Animal Biology, Cheikh Anta Diop University, Av Cheikh Anta Diop, Dakar, Senegal
2. Institut de Recerca de la Biodiversitat (IRBio) and Department de Biologia Animal, Universitat de Barcelona,
Av Diagonal 643, Barcelona 08028, Spain
Rationale
Red-billed tropicbirds (Phaethon aethereus) (fig. 1) occur across tropical waters of the Atlantic and
Pacific Oceans, and in the north Indian Ocean (Orta,1992). It holds approximately 2,000 pairs in the
western north Atlantic and less than 8,000 pairs globally (Lee & Walsh-McGehee, 2000). In western
Africa, It breeds only in Cape Verde and Senegal, but none of these two populations have been
well studied so far. In Senegal, the species holds only one breeding site in the Madeleine Island, a
small uninhabited volcanic island just 4km off Dakar (fig. 2).
Fig. 1: Red-billed tropicbird bird on nest
Methods
We monitored nests content every 15 days
from June 2014 to July 2015.
Results
Hatching success= eggs hatched / eggs laid
Fledging success= chicks fledged / eggs hatched
Breeding success= chicks fledged / eggs laids
Fig. 2: Location of Madeleine Island
Abundance and Breeding periodicity
Breeding success and nest mortality
Red-billed tropicbird was present all year Hatching and fledging success was estimated
round in Madeleine Island (fig. 3). The 77,96 and 73,91 respectively (fig. 5).
number of active nests (nest with an egg or a Overall breeding success was 57.6% (n=59
chick) increased from October to January, nests).
reaching 41 nests and 40 adults on the
island (fig. 3). Females laid a single egg
once a year. Laying peak was in January (19
eggs) and first hatching occurred in
CMYK - blue to green
November (fig. 4).
Discussion
The breeding cycle of red-billed tropicbirds in Madeleine Island is similar to that described in
Ascension (Stonehouse, 1962) but differs from the cycle described for the same species in the
Gulf of California, where seasonality is more marked (from November to June, Castillo-Guerrero et
al. 2011). Breeding success in Madeleine Island (58%) is similar to that reported in Ascension
Island (51%, Stonehouse1962) and greater than that reported from St Helena (11%, Beard et al.
2013).
Fig. 3: Abundance of adults and nests
In summary, red-billed tropicbird in Madeleine Island hold a small and vulnerable
population, breeding meanly in winter, although some breeders can be found throughout
the year. Currently, breeding success is relatively high.
REFERENCES
•!
•!
Beard A., Clingham E., Henry L. 2013. St helena seabirds report.
Castillo-Guerrero J.A.,Guevara-Medina M.A. &Mellink E. 2011. Breding ecology of the red-billed tropicbird Phaethon aethereus under
contrasting environmental conditions in the Gulf of California.Ardea99:61-71.
•! Lee D.S & Walsh-McGehee M. 2000. Population estimates, conservation concerns , and management of tropicbirds in the western
Atlantic.Carribb.J. Sci. 36: 267-279.
•! Orta J. 1992. Castillo-Guerrero J.A.,Guevara-Medina M.A. & Mellink E. 2011. Breding ecology of the red-billed tropicbird Phaethon aethereus
under contrasting environmental conditions in the Gulf of California.Ardea99:61-71.
•! Stonehouse B. 1962. The tropicbirds (Genus Phaethon) of Ascension Island. Ibis 103: 124-161
Fig. 4: Breeding phenology
90%
80%
70%
60%
50%
40%
30%
Acknowledgements
This work was conducted as part of Alcyon project funded by MAVA and implemented
by FIBA !and thereafter by BirdLife International. We thank the staff of the national park
of Madeleine Island and Paul Robinson for their support.
20%
10%
0%
hatching success fledging success breeding success
Fig. 5: Reproductive success
With the financial support of MAVA Foundation