California National Parks
- Channel Islands
Prince Island
- California Brown Pelicans Return
For the first time since 1939, endangered California brown pelicans are
nesting on Prince
Island, according to the Department of Fish and Game (DFG) and seabird
biologists from the
University of California, Santa Cruz (UCSC). As part of a contract with the
DFG Office of Spill
Prevention and Response (OSPR), biologists from UCSC counted 43 pelican
nests on May 16
during an aerial monitoring survey of seabird breeding colonies in the
Channel Islands National
Park and the Channel Islands National Marine Sanctuary.
Prince Island, located near
San Miguel Island at the north end
of the pelican’s main historical
breeding range in southern California, is one of three current breeding
locations in California;
pelicans nested there sporadically at least until 1939. Natural colony
re-establishment at Prince
Island and other historic breeding sites could reflect the continuing return
of this endangered
seabird.
The California brown pelican is a
subspecies of the widely distributed brown pelican. It
breeds in the Gulf of California, along the Sinaloa and Nayarit coast of
mainland Mexico, along
the Pacific coast of Baja California, and north to the California Channel
Islands. Non-breeding
pelicans range north along the Pacific coast as far as Washington and
British Columbia.
Following reproductive failure, severe population decline, and colony losses
from the 1940s
to 1970s, the California brown pelican was federally-listed as endangered by
the U.S. Fish and
Wildlife Service (USFWS) in 1970, and state-listed as endangered by the
California Fish and
Game Commission in 1971. The pelican is also identified as a Fully Protected
species in
California under Section 3511 of the Fish and Game Code. The USFWS was
petitioned to de-list
this subspecies in California in December 2005, and recently completed an
initial 90-day review
of that petition. The Service will now undertake a more comprehensive study,
known as a 12
month status review, to determine whether or not to propose the California
brown pelican for
delisting. The Service will also review the status of all brown pelicans
currently protected under
the Endangered Species Act (ESA) throughout their range as required.
The decline of the California brown
pelican caused by persistent marine pollutants was one
of the major events that helped to develop public concern for the
environment and related laws in
California in the late 1960s and early 1970s. Contamination by the pesticide
DDT resulted in thin
eggshells that broke under the pressure of incubating adult pelicans. The
pesticide was
determined to be the primary cause of reproductive failures and population
declines in southern
California and coastal Baja California, and was banned in the U.S. in 1972.
Human disturbance
of breeding colonies and roosts also contributed to population declines and
poor reproduction.
Oil spills and entanglement in fishing tackle are other known threats to
this species.
Recovery efforts in the last three decades have resulted in the seabird
again becoming a
common bird along the west coast of the U.S., after being reduced to small
numbers from the
1960s to 1980s.
Researchers from the University of
California, Davis, and California Institute of
Environmental Studies (CIES) began studying the remaining U.S. colony of
birds at Anacapa
Island in 1970. The size of this colony fluctuates annually (as is typical
of the species), but has
increased since the early 1980s to a mean size of about four to five
thousand pairs. In 1980, a
second U.S. colony was established at Santa Barbara Island and has been
monitored by CIES and
Channel Islands National Park. Since then, this colony has grown steadily
but with annual
fluctuations to several hundred pairs.
During the last year, CIES biologists
found other indications of the seabird’s continuing
recovery, including the first-known nesting at Middle Anacapa Island, small
numbers breeding
on East Anacapa Island (only the second time since 1928), and an expanded
distribution of
pelican nesting at Santa Barbara Island. Since the 1970s, numbers of
non-breeding California
brown pelicans have also increased dramatically in northern California,
Oregon and Washington.
UCSC aerial photographic surveys of seabird colonies in southern California
are being
supported by DFG–OSPR. Seabirds are vulnerable to impacts from oil spills
and chronic oil
pollution, as well as disturbance caused by human activities occurring too
close to breeding
areas. Using aerial photographs, seabird biologists are able to count birds
and nests to estimate
population sizes and trends for assessing continuing injuries to natural
resources from oil spills
and other marine pollutants. Aerial photographs are also used to study the
success rates of
restoration projects designed to assist natural recovery. DFG-OSPR provides
partial funding for
similar surveys in central and northern California.
