| Home: Special status species: California brown pelican: Natural history |
SPECIAL STATUS SPECIES: CALIFORNIA BROWN PELICAN
(Pelecanus occidentalis californicus)
NATURAL HISTORY |
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| General |
| Taxonomy: |
Order
Pelecaniformes; Family Pelecanidae. There are 5
subspecies of Pelecanus occidentalis: California
Brown Pelican (P. o. californicus); Caribbean
Brown Pelican (P. o. occidentalis); Eastern Brown
Pelican (P. o. carolinensis); Galapagos
Brown Pelican (P. o. urinator); Ecuador
Brown Pelican (P. o. murphyi).
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| Appearance: |
Like all
pelicans, this species is a large heavy bird with
a massive bill and huge throat pouch. Adults can weigh
up to 5 kg (11 lb) and have a wingspan of up to 2
m (6.6 ft).12
Males are usually larger than females.1
Both males and females have the same plumage that
is grayish-brown overall. During the breeding season,
adults of the California subspecies have a bright
red throat pouch, deep brown hindneck, and yellowish
crown. In the non-breeding season, the pouch is grayish-green
and the head and neck are white. Legs and feet are
black-gray. Pelicans have totipalmate feet (webbed
between all four toes) making them strong surface
swimmers, but somewhat clumsy on land. Brown pelicans
often fly in a single file line or V-formation, alternately
flapping and gliding. |
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| Feeding Behavior |
| Overview: |
Like all other pelican species,
Brown Pelicans may seize fish while sitting on the
water’s surface. However, the most common foraging
technique, the plunge-dive, is unique to this species.
Plunge-dive abilities and success rates improve with
age – adults are generally more successful than
immatures This species visits fishing piers and marinas
to feed on offal and discarded catch. |
| Prey Items: |
Brown pelicans
prey almost exclusively on surface schooling fishes,
especially Northern anchovies and Pacific sardines
on the West Coast. On the East Coast they largely
take menhaden, mullet, and minnows. Breeding birds
in the SCB relied almost exclusively on Northern anchovy
in the 1970s and 1980s.1
Beginning in about 1993, Pacific sardines (recovering
from population declines in the SCB) have become an
important component of the diet.29 |
| Method of
Capture: |
The Brown Pelican
flies above the water’s surface visually searching
for fish. Once fish have been located, the pelican
dives headfirst from heights of up to 20 m. Fish are
scooped up using the expandable bill and throat pouch.
Air sacs beneath the pelican's skin cushion the impact
of the dive and help the bird return to the surface.
Sitting on the surface, the pelican drains the water
from its pouch and swallows its catch. |
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| Reproduction |
| Overview: |
The Brown Pelican nests
in colonies. The male selects and defends a nest site
until a mate is obtained. The female builds the nest
using materials supplied by the male. Like most altritial
birds, newly hatched pelicans are blind, featherless,
helpless, and completely dependent upon their parents.
Large oscillations in breeding effort are normal at
most nesting colonies.5
Breeding activity appears to be influenced by many
environmental variables including food availability,
disease, human disturbance, harmful algal blooms,
and El Niño events.23 |
| Time to Maturity: |
4-5 years, with females tending
to begin breeding at a younger age than males |
| Longevity: |
Up to 43 years, but
fewer than 2% survive past 10 years12
|
| Breeding
Season: |
Peak egg-laying
tends to occur in March and April, but may begin as
early as November in some years or extend as late
as early August in other years; mean date of nesting
initiation is mid-February.5,29
Brown Pelicans are asynchronous breeders – several
cohorts may nest at different times in a single season. |
| Frequency
of Breeding: |
Brown Pelicans breed annually,
but adults may skip years when prey abundance is low. |
| Clutch Size: |
3 eggs (range 2-4);
mean young fledged per nest attempt in the SCB is
0.66 during the years 1985-2002.23
|
| Number of Clutches
per Season: |
One; replacement clutches
following loss of eggs or young are rare.25 |
| Parental
Care: |
Both males and females
share in incubation (29-32 days) and rearing duties
until fledging occurs at 12-13 weeks in the SCB.25 |
| Mating
System: |
Monogamous;
pairs are likely different birds in successive years
in the SCB.25 |
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