The Greenland White-fronted Goose Anser albifrons flavirostris

lands. This process was certainly underway when
the geese began to exploit the newly created
Sloblands in Wexford Harbour (probably at or
around 1910, Ruttledge & Ogilvie 1979), despite
the complete absence of boglands in the vicinity.
Despite their traditional habitat and high winter
site fidelity, these geese have shown an ability to
exploit new habitat opportunities. That said, only
one flock of White-fronted Geese is known to have
colonised and established an entirely new wintering
site since 1982. The process of exploiting
grassland habitats, either those that are seminatural
or of low intensity agriculture, has continued
to the present day. Although many flocks
still resort to peatland habitats to feed and sleep
at night, there are few flocks remaining that exploit
bogs by day (MS14, MS24). Norriss & Wilson
(1993) argued that this transition to more agricultural
grassland was not forced upon the geese
by habitat loss in very recent times, but that the
geese responded to the creation of more profitable
feeding habitats without loss of traditional
ones. This change has been occurring gradually
since the 1950s, and therefore does not coincide
with the dramatic increase in numbers that has
occurred since protection from hunting. Hence,
while it is possible to argue that increases in total
numbers since the 1970s have been associated
with increasing use made by the population of
more intensively managed farmland, this cannot
be anything more than a contributory factor enabling
contemporary increase, rather than the specific
cause. This is further supported by the fact
that the population range has effectively remained
the same in the last 20 years, although
several winter flocks have disappeared.
This ability to adapt to the exploitation of new
habitats may be linked to the availability of such
habitats in the neighbourhood of traditional flock
ranges. In areas of Scotland where extensive areas
of intensively managed grassland are available
(e.g. Islay, Kintyre, Stranraer), Greenland
White-fronted Geese have switched to these
whilst retaining traditional roosts. This process
has presumably run in parallel with improving
grassland management practices since the early
1960s. In areas with little intensive grassland
management and no tillage (e.g. many of the
Hebridean islands such as Jura, Mull, Skye and
Lewis) flocks remain small (see land use classification
maps in Mackey et al. 1998). Equally, in
areas with suitable extensive arable and managed
grassland but no traditionally used roosts, the
species is totally absent (e.g. in Ayrshire and large
areas of Dumfries). However, flocks with wintering
areas with the greatest area of improved grassland
within traditionally used areas have tended
to show increases in their number. This is in contrast
to those flocks where land use has changed
little, or agricultural land has been abandoned.
In this way, there appears some fitness consequences
to the availability of managed grassland
which affects the rate of change in local wintering
numbers, although it is far from clear if these
relate to annual adult survival, reproduction or
rates of immigration/emigration. Investigations
of these parameters in relation to habitat and individual
quality remain a priority for future research.
In contrast, it would appear from the evidence
presented here and in MS14 that, prior to protection,
the numbers of birds wintering at Wexford
and Islay were limited prior to protection by the
numbers shot. These two sites have held some
60% of the population since protection, hence this
limitation was a significant one. There are no accurate
collated hunting statistics for Islay. Since
protection on the wintering grounds in 1982, the
return rate of birds to Wexford and Islay has been
more or less constant. At Wexford, incorporating
the numbers killed into a simple model suggests
that the return rate has not changed since the late
1960s. Hence the product of annual survival and
emigration/immigration balance has remained
constant at around 88.4% over 3 decades of largescale
land-use change. The relative stable numbers
during 1968-1982 seem to have been due to
the balance between hunting off-take and changes
in annual breeding success. Immediately after
protection, numbers increased consistent with the
same probability of annual return rate. In the absence
of the hunt, this resulted in the increased
numbers. The increase has continued at rates
regulated by the potential of reproduction to replace
lost individuals.
Since the start of the 1990s, the numbers wintering
at Wexford have shown signs of decline due
to falling fecundity (chapter 6) and to catastrophic
losses of young and their parents in 1990, hence
declines in reproduction appear now to be limiting
the numbers at Wexford. Since the reduction
in fecundity is mirrored amongst the wintering
numbers on Islay and perhaps other wintering
areas as well, this seems to be a general phenomenon
in the population as whole in recent years.
On Islay, the reduction in reproduction rate has
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