American White Pelican - British Columbia has only one nesting colony of the provincially endangered American White Pelican - Province of British ...
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
American
White
Pelican
British Columbia has
only one nesting colony
of the provincially
endangered American
White Pelican.
Province of British Columbia Ministry of Environment, Lands and Parkspermit some increase in numbers. Ad- California, plus an isolated site on the
ditional human-caused disturbance Gulf Coast of Texas. The nesting range
can, however, tip the scales in the other extends northward into Canada to in-
direction. clude 30 000 or more nesting pairs at
Why are American White At some nesting colonies, distur- about 30 colonies that are found from
Pelicans at risk? bances caused by high-powered boats, British Columbia to the Lake of the
B
ritish Columbia has only one low-flying aircraft, or people walking Woods area of Western Ontario.
nesting colony of American White through colonies have caused serious There is little reliable information on
Pelicans. It is located at Stum Lake losses, and even complete abandon- whether the North American popula-
in White Pelican Provincial Park in ment. In the panic of such an event, the tion of American White Pelicans is
the Chilcotin region, 70 kilometres west fleeing adult pelicans often crush eggs increasing or decreasing, because there
of Williams Lake. Because these colonial or knock them out of the nest. The has not been a continent-wide survey
birds are migratory, have only a single untended eggs or small nestlings are of all colonies in a single year. The total
nesting site, and feed on fish in shallow then quickly preyed on by gulls, ravens, of 50 000 pairs may seem substantial,
lakes sometimes hundreds of kilometres or crows, or may die from exposure to but most of these nest in a few large
from Stum Lake, they are particularly cold rain or searing sun. At Stum Lake colonies which makes them especially
vulnerable to a variety of threats. about one young reaches the fly- vulnerable.
At Stum Lake, both natural and hu- ing stage for every two eggs laid. The American Although not
man-influenced events can affect nest- This is typical for American
ing success. Fluctuating water levels are White Pelicans.
White Pelican included in the
federal Migra-
the most frequent natural cause of Some pelicans also die from a has been legally tory Bird Con-
colony abandonment. In drought years, variety of causes during migra-
nesting islands become connected to the tion or while on their wintering
designated as vention American
Act, the
mainland, allowing access to land-based grounds, including shooting, an Endangered White Pelican
predators. A single severe flood or a se- disease, adverse weather, or en- is protected by
ries of wet years can result in inundation tanglement in fishing gear.
Species state and pro-
of islands. Over the thousands of years Although British Columbia’s in British vincial wildlife
they have existed on this continent, only nesting colony of white peli- laws. In British
white pelicans have been able to cope cans appears to be holding its
Columbia. Columbia the
with these natural events and maintain own, it is also evident that hu- species is pro-
their overall population. In recent dec- man-caused disturbances, mortality, tected against killing, capture, or harass-
ades, however, various drainage, irriga- and habitat degradation are taking their ment under the Wildlife Act. It is on the
tion, and diversion projects, particularly toll on the species across its range. provincial Red List, and has been legally
in the United States, have resulted in the Surely these magnificent birds deserve designated as an Endangered Species in
demise of some colonies. better treatment in future years. British Columbia.
In some years, predation may have
drastic effects on a colony. In 1972, What is their status? What do they look like?
P T
coyotes swam to a nesting island in elicans were first reported nesting at he American White Pelican
Stum Lake after the young had hatched, Stum Lake in 1939. There has been a (Pelecanus erythrorhynchos) is un-
and decimated the colony; only 10 fairly steady increase from about 100 mistakeable. Its huge size (wingspan
young fledged from 116 nests. More fre- nests in the early 1980s to over 400 in 2.4 to 3.0 metres; weight 6 to 7
quently, coyotes cross to the islands on 1993, although numbers fluctuate from kilograms), snowy white plumage with
ice and cause the earliest nesters to year to year. jet-black wing-tips, and huge orange-
abandon their nests. These birds usually The world population of the Ameri- yellow bill and pouch, distinguish it
re-nest successfully a week or two later can White Pelican is estimated at about from all other species.
when the ice has melted and the island is 50 000 nesting pairs, entirely confined In flight, white pelicans are a spec-
more secure. to North America. In the United States, tacular sight. Almost always in groups,
Despite the natural losses described 15 000 to 20 000 pairs nest at about 15 they fly gracefully in precisely spaced
above, enough pelicans normally sur- widely scattered colonies in the north- lines or “V” formations, flapping slowly
vive to maintain colony size, and even to ern plains, Rocky Mountain states, and in unison half a dozen times, thengliding, then flapping and gliding again. short tail, short stout orange-red legs, The American White Pelican is gen-
They fly with the neck held back against and large webbed feet. Male and female erally a silent bird, but on the breeding
the shoulders, and the bill resting pelicans are similar in appearance, al- grounds it utters low-toned grunts or
against the breast. Whooping Cranes, though females are slightly smaller. subdued croaks. Sounds of fledglings
Snow Geese, and swans all fly with In late winter and spring, adult white have been described as a low “coughing,
outstretched necks. Despite their pelicans develop a horny projection, whining grunt.”
ungainly appearance, white pelicans roughly triangular in shape and about 4
are excellent gliders and agile fliers. centimetres high, on the upper bill. At How do they reproduce?
A
When leaving a migration rest-stop, this time they also show some pale yel- merican White Pelicans nest in
or heading to a foraging lake from the low feathering on the crown of the head colonies from a few to several thou-
nesting island, they often catch thermal and upper breast, and the bare skin sand pairs, on islands in lakes, reser-
air currents and soar to great heights, around the eye turns orange-yellow. voirs, or large rivers. At Stum Lake,
even disappearing from view. Their These breeding season characteristics there are two preferred nesting islands.
descent from such heights may be disappear in early summer. Juvenile Colony sites are relatively flat, have bare
spectacular as they drop like meteors, white pelicans have greyish feathers ground or low plants but no dense tree
the wind rushing with a roar through during their first summer and autumn. or shrub growth, and are situated fairly
their half-closed wings. During normal The large, naked pouch of pelicans is close to the water but out of reach of
flight, which is about 50 kilometres per connected to the throat, and is very waves. Islands are undoubtedly chosen
hour, every motion is easy, unhurried, expandable. It is used to catch fish, as a because land-based predators cannot
and graceful. dish from which nestlings can feed on easily reach them.
When at rest with the wings folded, regurgitated fish, and for display during Courtship begins immediately after
almost no black is visible. On the water courtship. It can also be fluttered in and arrival at Stum Lake in late April. A pair
they float with surprising buoyancy. out to promote cooling. Contrary to bond is formed when a male can suc-
Other characteristics of pelicans include popular belief, pelicans do not fly with cessfully defend his chosen mate from
a hook on the end of the upper bill, a fish in their pouches. other males. The mated pair thenengage in curious rituals such as pouch fledglings that have joined a pod, but Present distribution of the
displays and bowing, and the female both parents are kept busy bringing American White Pelican in
Canada and the United States
selects a nest site. food to them at this stage, which lasts
Nests are about 60 cm across, and until they can fly at 7 to 10 weeks of age.
may be made of a mound of soil, plant Young American White Pelicans
material and debris with a hollow in the may wander widely for the first two
middle, or may merely be a scrape on years of their lives, but will return to
bare ground. They are about one metre Stum Lake to nest when they are three
apart – just enough that neighbouring years old. The maximum lifespan may
pelicans can’t reach each other. At Stum reach 17 years.
Lake, nests are scraped into shape three
or four days after the pelicans arrive. What do they eat?
T
Most eggs at Stum Lake are laid in the he American White Pelican is
first 10 days of May. piscivorous (fish-eating). It doesn’t
White pelican eggs are large (about 9 dive underwater like its close relative
cm long) and dull white, with a coarse- the Brown Pelican, but feeds from
textured, chalky surface. They often be- the surface on fish that live in shallow
come quite stained as incubation pro- water. The diet of the white pelican var-
ceeds. The usual clutch is two eggs, but ies considerably, but includes carp,
varies from one to three, with an average perch, suckers, catfish, chub, and shin-
at Stum Lake of 1.8. Incubation takes ers, fish that are at home in shallow, of-
about 30 days and involves both adults, ten warm waters. Other aquatic animals
which faithfully replace one another such as frogs, salamanders, and crayfish
every one to three days. sometimes supplement the pelican diet. occurs in British Columbia too. While
Nesting events at Stum Lake have There is little information on pelican at the foraging lakes the pelicans
been delayed by a few days, or even food habits in British Columbia. Bones actually spend more time loafing than
weeks, in years when serious distur- of squawfish and sucker, fish which are catching fish. This mostly involves
bance occurred during the egg-laying or abundant in shallow lakes where the preening and resting activities.
early incubation period. Stum Lake birds forage, have been In British Columbia, as in other ar-
Young pelicans are naked and help- found at the nest site. eas, white pelicans may feed individu-
less when born, but have thick white There are few fish in Stum Lake, ally or in cooperative social groups.
down within a week. They can stand at and pelicans do not feed there. Instead When feeding alone they thrust their
three weeks, and leave their nests they make regular bill into the water and normally catch
and congregate in juvenile groups Pelicans feed flights to lakes one fish at a time. This may be done
called “pods” by their fourth while swimming in deep water or walk-
week. While in the nest the
at lakes up to scattered over
20 000 square kilo- ing in shallows. Social feeding involves
youngsters are dutifully tended km away, metres of the groups of 10 or more pelicans which
by both parents, which brood form a semi-circle facing the shore, and,
them in cold weather, shade them
scattered over Fraser Plateau,
and up to 164 km with vigorous wing-flapping and
when it is hot, and guard against square away. Common splashing, herd schools of fish into a
predators. The two parents ex- confined area in shallow water where
change these duties each day.
kilometres of fish in the main
foraging lakes, in they are easily caught.
While one is at the nest, the other the Fraser addition to squaw-
is away catching fish. fish and suckers, Where do they live?
Plateau.
A
Very small nestlings are fed include shiners, merican White Pelicans are highly
liquid food from the tip of the chub, whitefish, migratory. Those which nest at
adult’s bill. As the young grow they and rainbow trout. Most feeding activ- Stum Lake spend the winter in
probe aggressively into the parents ity occurs in morning and evening southwest California and the Pacific
pouch for regurgitated, half-digested hours, but night-foraging is known to coast of Mexico, while birds from colo-
food. The adults show less interest in occur in other areas, and probably nies on the Great Plains mostly wintersouth to Florida, the Gulf Coast, and autumn records of pelicans in the the last two weeks of April. Visits to the
east coast of Mexico. Cariboo-Chilcotin region. Most au- nesting site at Stum Lake, in White Peli-
White pelicans enroute to British tumn (September-November) records can Provincial Park, are strongly dis-
Columbia begin to leave their southern of pelicans in British Columbia are from couraged because the birds are easily
wintering grounds in March. Most en- the Thompson-Okanagan region. disturbed. At some of their foraging
ter the province via the interior of The autumn migration out of British lakes, such as Alkali Lake, the pelicans
Washington and move north and Columbia seems generally to follow the have become accustomed to people and
northwest through the Okanagan and spring route, but is more leisurely, and passing traffic and may be readily ob-
Nicola valleys, and on to Alkali and the flocks are smaller (usually less than served from a respectful distance, pri-
Stum lakes. In spring, the birds marily in June and July, with-
are spurred on by the urge to out harmful disturbance.
nest, and the migration period is
brief. Peak migration time in the What can we do?
I
Okanagan occurs between April n order to provide protection
15 and 22; most pelicans arrive for the only nesting colony of
at Stum Lake between April 20 American White Pelicans in
and 30. Flocks of 10 to 30 or British Columbia, Stum Lake
more birds are not uncommon and the immediate lands sur-
during spring migration. rounding it were given Provin-
White Pelicans have been cial Park Status in 1971, and
seen in summer on 50 or more named White Pelican Provin-
.
lakes scattered widely across the R. Wayne Campbell photo cial Park. To provide further
Fraser Plateau. The lakes used protection, and to heighten
most regularly have abundant non- 10 birds) and more widely dispersed. awareness of the vulnerability of this
game fish populations, shallows suitable The migration through the Okanagan bird in the province, it was designated
for catching fish, and safe sites for the Valley extends from late August to late as an Endangered Species under the
birds to rest or “loaf” on, such as barren November. There are occasional au- British Columbia Wildlife Act in 1980.
islands, sand- tumn records for the West BC Environment and BC Parks staff,
bars at river In winter, Kootenay, Shuswap, and south with the assistance of naturalists, con-
deltas, or logs coast areas as well. duct annual counts, make periodic pa-
lying in shal-
pelicans from During migration, lakes such as trols to control disturbance of nesting
lows around British Columbia Osoyoos, Skaha, and Vaseux in pelicans by recreationists, and encour-
lake margins. the Okanagan Valley, and age people wishing to see or photograph
The most im-
frequent coastal Stump, Nicola, and Chapperon pelicans to visit pelican foraging lakes
portant forag- bays, lagoons, lakes in the Nicola Valley, pro- rather than Stum Lake. Pilots have been
ing lakes such vide temporary resting and feed-
as Abuntlet,
and estuaries ing sites for white pelicans. In
Alkali, Chil- from central winter, pelicans from British Co-
cotin, Kluskus, lumbia frequent coastal bays, la-
and Pantage
California to goons, and estuaries from central
mostly have southern Mexico. California to southern Mexico, as
average depths well as some inland waters in
of 1 m or less, and have suitable loafing California. These migration and winter-
sites at them or nearby. ing habitats are extremely important for
By mid August, the young can fly and long-term survival of pelicans that nest
pelicans are no longer tied to the nesting in British Columbia.
islands at Stum Lake. Whether they Pelicans may occasionally be ob-
continue foraging at lakes on the Fraser served on lakes or in flight during their
Plateau in late August and September spring migration through south-central .
isn’t known, since there are very few British Columbia, which is at a peak in R. Wayne Campbell photo . .
David Dunbar photo R. Wayne Campbell photo
advised not to fly lower than 600 m threat as the human population of Brit-
over the colony from May to August. ish Columbia grows, logging roads
Fishing, trapping, hunting and dis- creep closer to pelican lakes, and more
charge of fire- and more people wish to view
arms are not The public is this intriguing species.
permitted at Although the current status
Stum Lake be-
asked to respect of the American White Pelican
tween March 1 the solitude that in British Columbia is encourag-
and August 31. ing, its long-term future is uncer-
Research
these great white tain. The public is asked to
studies of great birds need. respect the solitude that these
value for pro- great white birds need, and to
tecting and managing white pelicans support programs that will ensure
have been carried out at Stum Lake and they are always part of our precious .
R. Wayne Campbell photo
surrounding areas. A preliminary re- wildlife heritage.
covery plan has been prepared consid-
ering matters such as boating, aircraft, , :
and firearms restrictions, enhancement Wildlife Branch
and protection of foraging habitat, im- BC Environment
provement of nesting islands in Stum Ministry of Environment, Lands and Parks
Lake, prevention of predator access to 780 Blanshard Street
the islands, and potential for starting a Victoria, British Columbia V8V 1X4
second nesting colony in the province.
BC Environment personnel have
banded or colour-marked over 1000 ju-
venile pelicans at Stum Lake since 1968.
As band returns and sightings accumu-
late, they provide valuable information
on migration routes and habitats, and
on locations, causes, and rates of mor-
tality of Stum Lake pelicans when they Corporate Resource Inventory Initiative
are outside of British Columbia. (Province of British Columbia)
Future management emphasis will
--- .
be on protection of nesting and foraging
. ,
pelicans and their habitat from human
disturbance. This is an ever-increasing
Printed in British Columbia on recycled paper with vegetable base inks.
.. You can also read
