Barnacle Geese on Kolguev Island 59
©Wildfowl & Wetlands Trust
Wildfowl
(2013) 63: 56–71
major studies were undertaken in the centre
of the island and eastern parts were visited
for short periods. In 2011–2012 the field
camp was situated in the upper Peschanka
River catchment, 10 km upstream from the
camp position in 2007–2008.
Estimates of total colony size, extent,
structure, nesting success and nesting
densities in various parts of the Peschanka
River delta colony were based on the data
published in Anisimov (2007). For the
colonies situated in the central part of
Kolguev (
i.e.
> 5 km from the coast) surveys
were made on foot and by boat along
predetermined census routes. The same
boat routes were followed in each year;
walking routes extended each year as new
colonies were discovered, and previously
found colonies were visited and surveyed in
the same way in all years. Checks were made
of all lakes and creeks in the 200 km
2
study
area in 2008 and 2011 to determine flock
distribution in the region. Peregrine Falcons
are most active in defending a territory of
150–300 m around the nest (Kharitonov
2007) and this defensive behaviour makes
these “protected” areas attractive to several
goose species for establishing nesting
colonies. Dense nesting aggregations
therefore were defined as “colonies” on the
basis of their distance from the nest of a
protecting falcon, and also on the
c
. tenfold
increase in goose nesting densities around
falcon nests, in comparison with nesting
densities elsewhere on central Kolguev
Island. During the surveys we counted the
number of all Barnacle Goose nests located
(sites illustrated in Fig. 1), mapped them
with GPS and subsequently checked the
hatching success of all mapped nests during
visits to the colonies in the second half of
July. Nests where at least one egg membrane
was present, indicative of hatching, were
considered to have been successful. During
2006–2012, we found and described 1,194
Barnacle Goose nests at 43 inland colonies
(23 different colony sites). The fate of 1,029
nests was estimated for the 28 colonies
found in the central part of the island.
Counts of broods and moulting groups
were made for all geese species in late July –
early August, both on predetermined and on
arbitrarily-selected routes along the rivers
and in the lake areas. These route censuses,
of 1,666 km (summed for all seasons in the
central part of Kolguev), found 4,600
Barnacle Geese broods and 27,600 moulting
individuals.
Results
Transect counts conducted in 2006 enabled
Anisimov (2007) to estimate the Barnacle
Goose colony size in the Peschanka River
delta. The number of paired individuals
recorded in the delta (ranging from 1,600
geese in 1989 to 90,000 in 2006) comprised
up to 18% of the entire Russian-breeding
population (Table 1). Nesting density,
calculated on the basis of transect counts
made in different part of the colony, gave
values varying from 750–6,000 nests/km
2
,
with the most common nesting densities
being of 1,500 nests/km
2
(Anisimov 2007).
Our own more general observations of the
colony in subsequent years found no
obvious changes in nesting densities for
areas occupied by the colony during
Anisimov’s study, but it was noticeable that
the overall area covered by the colony had
expanded. Whereas in 2006 there had been
