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Status
Change
During the past 100 years, the
Brant has declined drastically as a wintering species in
British Columbia. In the late 1800s, Fannin (1891)
considered Brant an "abundant winter resident."
Recollections of a former market hunter, summarized by Leach
(1982), best illustrate the populations that were present
before the twentieth century.
When Henry Weaver, a market
hunter, began fowling in 1895 at the age of 14: the shores
of Mud Bay and Boundary Bay were at times solid with flocks
of [Black] Brant. They came in so continuously to
decoys that on one occasion he and eight other hunters took
turns shooting from a single blind and picked up 128 birds
in the course of a few hours.
Leach also mentions:
Market hunters on Vancouver
Island and the Lower Mainland [Fraser River delta]
were especially busy in December shooting large numbers of
Brant for sale at Christmas, when they fetched 50 cents a
brace. A market hunter named Franklin shipped two sacks of
Brant on a twice-weekly boat to Victoria and others to
Vancouver. In one good year, he and a companion sold 2,500
Brant to Pat Burns and Company before New Year's
Day.
By the 1920s, Brooks and
Swarth(1925) describe the Brant as a "common winter visitant
to the coast . . . in former years more generally
distributed than at present." By the mid-1940s, the Brant
was still considered a winter visitant, but much more
abundant as a spring transient (Munro, J.A. and Cowan
1947).
The decline of wintering Brant
continued during the next 30 years; this is well documented
by annual surveys and censuses, mostly from the Queen
Charlotte Islands and Boundary Bay. The population of Brant
at Masset in January 1952 was estimated at 1,000 birds
(Leopold and Smith 1953). Today (1986), flocks of up to 6
birds are reported there infrequently. However, annual
Christmas Bird Counts at Skidegate Inlet (90 km to the
south) have shown an increase from 129 birds in 1982 to 283
in 1984, and some birds are frequently seen on the Yakoun
River estuary and at Sandspit.
The decline is also documented
in the vicinity of Boundary Bay. In December 1944 and 1946,
at least 500 Brant were counted off Crescent Beach (Holdom
1945, 1947). Numbers peaked there at 1,000+ birds on 14
January 1947, but by 1951 they had decreased to about 200
birds (Munro, D.A. 1952). Christmas Bird Counts at Ladner
from 1957 to 1984 also show a decline in the average
wintering population. Numbers dropped from 600 to 83 birds
between 1960 and 1962. The decline continued to 4 birds in
1983; none were found in 1984. Between 1975 and 1984, the
winter population, based on Christmas Bird Counts at
Skidegate Inlet, Ladner, and White Rock (Surrey), averaged
only 28 birds per count (n=23).
During the past 30 years, the
proportion of Brant that winter along the Pacific coast
north of Baja California declined from 50% to 65% of the
population to less than 10% (Kramer et al. 1979). That
decline coincided with increasing numbers of Brant wintering
in Baja California and along the west coast of Mexico (see
Smith, R.H. and Jensen 1970). The population shift was
attributed to harassment and disturbance of birds by people
(Denson 1964). Winter surveys, however, from 1951 to 1974,
indicate the population along the Pacific coast has remained
relatively stable at 140,000 birds (Smith, R.H. and Jensen
1970; Bellrose 1976). In 1987 the population was reported to
be 146,992 birds (Conant 1988). Of those, 116,696 were
counted in Mexico, 8,385 in Alaska, and 21,911 at other
locations.
OCCURRENCE: The Brant is widely
distributed along coastal British Columbia, particularly the
inner coast; it is rarely found in the interior. It occurs
principally on estuaries, beaches, bays, lagoons, and mud
flats. It is extremely rare any distance from the ocean. In
British Columbia, it occurs chiefly as a spring migrant,
during which time thousands are widespread along the coast
littoral. Some of that northward movement, however, occurs
well offshore (see Martin and Myers 1969; Hatter et al.
1978).
Spring populations build in
California bays in early January and peak in mid-March
(Moffit 1939). Spring migration occurs from late February
through mid-May and peaks in late March and early April in
extreme southern British Columbia. Aerial counts at Boundary
Bay during the spring of 1958 (Taylor, E.W. 1959) show a
rapid build-up to a peak in late March followed by a gradual
decline throughout April and May. Similar trends have been
noted at the Little Qualicum River estuary (Dawe 1980),
following a Pacific herring spawn there, while near Campbell
River the peak movement occurs slightly later. Most of the
spring movement is visible passing northward up the Strait
of Georgia. Areas of concentration are Boundary Bay and the
east coast of Vancouver Island from Victoria to Campbell
River. Daily fluctuations of numbers there probably indicate
a continual turnover of migrants. E.W. Taylor (1959) notes
that spring migration in the Boundary Bay area appears to be
more gradual than in other areas of concentration in the
Pacific Northwest.
Small numbers, usually
individuals but occasionally flocks of up to 200, may occur
in summer on estuaries and bays, along the coast. Flocks
reported in June are probably non-breeding wanderers.
First-year birds add common in north-bound flocks into late
June (T. Tolish pets. Grimm.).
Fall migrants are rare along
the British Columbia coast. Most of the population stages at
Izembek Lagoon, Alaska and then departs en masse offshore,
in a rapid, direct flight to wintering grounds in Mexico
(Hansen and Nelson 1957; Jones, R.D. 1973). Small numbers of
Brant occur along the British Columbia coast from late
August through October. Those birds are likely nonbreeding
adults or immatures. Occasionally, the direct autumn flight
from Alaska is witnessed at sea off Vancouver Island. R.D
Jones (pers. comm.) suggests that migration routes
illustrated by Einarsen (1965) and Bellrose (1976) should be
modified. He contends that wind conditions prevailing at the
time the southward migration occurs are such that great
turbulence would be encountered if the birds swung as far
east as those routes show. Moreover, Einarsen and Bellrose
indicate coastal travel over at least a part of the trip,
which is contrary to what Moffit (1939) observed. Jones
contends that since westerly winds blow around the north
side of the Pacific High, the majority of birds fly a
strictly seaward route south on the back quadrant of a low
centre to pick up the westerlies and fly favourable winds to
Baja.
Only small numbers of Brant now
winter in British Columbia; Masset and Skidegate inlets
alone support sizeable winter populations.
Flocks of Brant that appear in
British Columbia in February and March are composed almost
entirely of mated pairs. W.T. Munro (1979b) shows that 90%
of the Brant harvested in the province are adults. The late
winter/early spring hunting seasons in British Columbia,
when in effect, concentrate the kill on birds that would
soon be nesting.
The distribution of Brant in
the province is closely related to the distribution of
eel-grass (Zostera marina) which is the Brant's
most important food (Cottam et al. 1944). Examination of gut
contents from 50 Brant shot by hunters in Boundary Bay in
early March 1988 showed that 94% of the diet (by volume) was
Z. marina, the remaining plant food being Z.
japonicus, a smaller, non-indigenous eelgrass; trace
amounts of Pacific herring eggs were found in some birds (A.
Reed pers. comm.). Observations in the Qualicum Beach and
other areas indicate that the algae, sea lettuce (Ulva
lactuca), is taken in large quantities later on during
spring migration.
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This
information was scanned from The Birds of British Columbia (Campbell
et al.), Volume I, pages 272-275. Volumes I, II and III of The Birds of British
Columbia, can be ordered electronically at: orders@ubcpress.ubc.ca from UBC
Press in Vancouver, British Columbia.
Nests