Description
Brown
Pelicans are large (3-5 kg) mostly dark brown birds with white to
pale yellow necks and black feet and legs. Their most distinguishing
feature is a long beak (23-34 cm) with a hooked tip and a huge pouch.
Their legs are short and all four toes are webbed. Their wing span
is more than 2 meters, they soar well, and often glide low over
the water. The sexes are alike.
Distribution
and Habitat
There
are seven or eight species of pelican in the world. Brown Pelicans
breed from Anacapa Island, California south to Chile and from Maryland
to Venezuela and Trinidad. After breeding, they may be seen as far
north as British Columbia and Nova Scotia. They are the only species
of pelican that is strictly marine in habitat, never found more
than 20 miles out to sea or inland on fresh water. They prefer shallow
inshore waters such as estuaries and bays.
Diet
Brown
Pelicans feed on mid-sized fish that they capture by diving from
above and then scooping or dipping the fish into their pouch, which
acts as a flexible dip net. Although they do feed on anchovies and
sardines most of their prey has little commercial value. They are
the only species of pelican that hunts with such dramatic plunging
dives. After capturing the fish they rise to the surface and drain
the water from the pouch. They point the bill up and swallow the
catch. They are often robbed of their catch by gulls before they
get the chance to swallow. Juvenile Brown Pelicans have been observed
fishing in the manner of the other pelican species, by swimming
on the surface of the water. The pelican's beak can "really
hold more than its belly can". The pouch holds about three
gallons, the stomach about one gallon. They also take some invertebrates.
They are familiar sight around fishing ports within their range,
where they roost on piers, docks, and fishing boats feeding on scraps.
Reproduction
Nesting
is on islands by preference. On the Southeast coast, it is often
in mangroves, where the birds build a rather flimsy nest of sticks,
reeds, bones, and seaweed. On islands without predators, they often
build on the ground. They nest in colonies, and are sensitive to
disturbance by tourists and fisherman while breeding. There usually
lay two or three eggs in March or April. Incubation lasts 28 to
30 days. Both parents care for the naked, helpless chicks. They
feed their chicks by regurgitation. Fledging requires 63 to 76 days,
with little or no post fledging care depending on the length of
time the young spent in the nest. Sexual maturity is reached after
two to five years.
Conservation
Although
globally abundant, Brown Pelicans were once severely endangered
in the United States. The major cause of their decline was pesticide
poisoning. Since DDT was banned, there has been a full recovery
on the east coast and other populations are showing steady improvement.
Threats today include becoming snarled in abandoned fishing lines
and flying into overhead wires. The Zoo's birds are rehabilitated
birds, which were injured in this fashion. Other factors include
human disturbance of nesting colonies and reduction of fish stocks
by excessive commercial fishing.
References
- Del
Hoyo, J., Elliot, A. and J. Sargatal. eds. 1992. Handbook of the
Birds of the World. Vol. 1. Ostrich to Ducks. Lynx Edicions, Barcelona.
- Ehrlich,
P. R., Dobkin, D. S., and D. Wheye. 1992. Birds in Jeopardy. Stanford
University Press, Stanford.
- Harrison,
P. 1983. Seabirds. Houghton Mifflin Company, Boston.
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