Distinguishing Features
Grebes are "tailless"
water birds that are excellent swimmers and divers. They have lobed
toes; not fully webbed ones. As in loons, their legs are attached
far back on their body, so they move awkwardly on land. The Western
Grebe is a large grebe, with a long slender neck, sharply contrasting
black and white colouration and red eyes. The bill is slender, sharp
and slightly up-tilted and greenish-yellow in colour (Godfrey, 1986).
Distribution
Columbia Basin: One of only three
regular breeding locations in B.C. is located at Duck Lake near
Creston (Creston Valley Wildlife Management Area).
British Columbia: Regular breeding
populations are restricted to Salmon Arm, the north arm of Okanagan
Lake, and Duck Lake near Creston. Winter populations are widely
distributed along the coast and sparsely and locally distributed
on large, open bodies of water in the interior. Formerly bred at
Williams Lake, and Swan Lake near Vernon. A colony at Kamloops Lake
was used only in 1973 and a pair bred at Westham Island in 1986
(Cannings et al. In prep.).
Global: Breeds from sc. British
Columbia, c. Alberta, c. Saskatchewan and sw. Manitoba south to
New Mexico, Nebraska, Iowa and Minnesota. Winters along Pacific
coast, more uncommonly inland, from s. British Columbia south to
c. Mexico (Cannings et al. In prep.).
Habitat
Nesting habitat includes emergent
vegetation along the margin of medium to large lakes although they
occasionally nest on floating vegetation in the open. Nests consist
of large masses of vegetation over bases constructed of decaying
bulrush, cattail, or reed canary grass. Other attributes essential
to good nesting habitat are a long ice-free period with stable water
levels, access to open water that is deep enough to allow substantial
fish populations, protection from wind and waves, and minimal human
disturbance. Small numbers of grebes winter in the interior in large
lakes and sloughs, and slow-moving rivers (Cannings et al. In prep.).
Threats
Widely distributed and globally
secure. However, breeding population in B.C. may be fewer than 200
pairs. Breeding populations are declining, with five historically
used sites now reduced to three. Human disturbance (primarily wave-wash
from powerboats) directly threatens nesting sites through increased
annual reproductive losses and/or colony abandonment. An expanding
colony of Ring-Billed Gulls may be a threat to the colony at Shuswap
Lake. Large aggregations of wintering grebes are vulnerable to oil
spills (Cannings et al. In prep.).
Biology
Western Grebes feed mainly on fish (80 - 100% of
the diet), but crustaceans, worms, and insects are occasionally
taken. Spring migration is generally from late April to early May
with most birds having left the coast by mid-May. Autumn migration
is greatest from mid-September to mid-October. Brood size varies
from 1 to 4 in British Columbia, and hatching occurs mainly from
late June to early July (Cannings et al. In prep.).