II-1. WATERBIRD UTILIZATION OF EAGLE RIVER FLATS
9
The first half of the summer of 2000 was gen-
or species groups of waterbirds is presented
erally dry, and ERF ponds were low or dry,
below.
similar to water conditions throughout Cook
Swans
Inlet. Frequent flood tides put water into ERF
Tundra swans (Columbus columbianus) and/
but drained off rapidly. Extensive pumping
or trumpeter swans (C. buccinator) utilized
was effective in drying large portions of ERF
in 2000. After pumping ceased in mid-August,
ERF only in small numbers during the spring
ponds gradually refilled in most areas. Fall
of 2000, with 4 observed on 27 April (Table II-
high tides, which generally occur in late Au-
1-1). Higher swan numbers in spring may have
gust or early September, did not occur until
been missed because of the small number of
early October in 2000. The ponds on ERF be-
surveys. Swans were observed in Areas B and
gan freezing, with periods of thawing, in mid-
D, similar to other years (Fig. II-1-3).
October.
In fall, swan numbers peaked in mid-Sep-
tember at 189 birds, lower than in other re-
cent years except 1999. The fall mean of 28
Abundance and distribution of waterbirds
swans was among the lowest recorded since
on ERF
Twenty-four aerial surveys were conducted
surveys began in 1988. Swans utilized Areas
in 2000, somewhat less than in recent years,
D, B, and CD most during fall (Fig. II-1-3), as
but a comparable number of fall surveys were
in other years. One dead swan was observed
flown. Numbers of birds by species or spe-
in Area D, pond number 5, during fall surveys.
cies groups are listed by survey date in Table
Geese
II-1-1 and Figure II-1-2. Utilization of ERF
study areas by major waterfowl groups by
Peak counts of geese occurred on 27 April,
primarily lesser snow geese (Chen caerulescens
season is presented in Tables II-1-2 and II-1-3.
caerulescens) (Table II-1-1, Fig. II-1-4). Snow
A discussion of utilization of ERF by species
Figure II-1-2. Numbers of swans, geese, and ducks counted on ERF dur-
ing aerial surveys in 2000.
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