64 Barnacle Geese on Kolguev Island
©Wildfowl & Wetlands Trust
Wildfowl
(2013) 63: 56–71
associated colonies (F_16 and F_20, 0.6–
2 km from the new colonies), which also
increased in size markedly in 2012 (Table 2
and Fig. 2). Several solitary nests (
i.e.
without
raptor protection, but which in four out of
eight cases hatched successfully) were also
recorded in 2011 and 2012 in the area
between these four colonies (Fig. 2).
Previously, two cases of solitary nesting by
Barnacle Goose pairs, at distances > 2 km
from a colony, were observed in 2008, but
both of these breeding attempts were
unsuccessful as a result of fox predation.
Barnacle Goose distribution over the
island changes radically during the post-
hatching period. During nesting, all central
colonies typically support no more than
500–1,000 pairs (
i.e
. < 1% of all the nesting
population of the island), yet late summer
counts made in early–mid August indicate
that one-third of all broods of this species
move to central Kolguev after hatching,
when all broods (including broods from late
nesting pairs) leave their colony sites, when
even the earliest-hatched goslings are not yet
able to fly. These counts give densities
ranging from 5–20 broods/km
2
across the
different habitats. Given that the total area
of prime Barnacle Goose brood-rearing
habitats (
i.e.
where such high densities were
observed) is at least 800 km
2
, we roughly
estimated that the habitats of central
Kolguev could support up to 16,000 broods
(Kondratyev
et al.
2012). Non-breeders also
Table 3
. Some parameters associated with Barnacle Goose colonies monitored in the central
part of Kolguev Island in 2006–2012.
Inland colonies
2006 2007 2008 2011 2012
Falcon territories inspected
6
14
15
8
10
Falcon territories with BG colonies
3
7
11
7
10
around (including years when falcons
skipped breeding)
Falcon territories with
Anser
colonies around 2
5
6
4
2
Number of
Anser
nests in monitored falcon 46
40
50
10
7
associated colonies
% of falcon territories with BG colonies
50
50
73
87
100
Number of colonies monitored
3
7
11
9
11
Number of nests in monitored colonies
32
115 > 156 317 > 616
Mean colony size
10.7 12.8 11.3 39.4 52.4
(± s.d.)
(6.1)
(17.1)
(9.0)
(15.2)
(39.2)
Per cent of successful nests in all checked
91
69
71
74
70
inland colonies
