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CALIFORNIA
CONDOR NEST RECEIVES A LIVE CONDOR EGG; WILD CONDOR EGG HATCHES
AT LA ZOO
Biologists from the U.S. Fish and Wildlife Service and Los Angeles
Zoo this week switched an artificial California condor egg with
a captive-reared egg that is expected to hatch soon in hopes
that the endangered birds will learn how to raise a chick in
the wild at their nest in the Los Padres National Forest in
Santa Barbara County.
Meanwhile, an egg
retrieved from the same nest three weeks ago that would likely
not have survived in the wild hatched June 17 at the Los Angeles
Zoo after receiving extensive care from biologists there. The
chick is being raised by captive adult condors that have previous
parenting experience. The young condor, whose sex has yet to
be determined, appears to be in good health and the captive
birds have accepted the newly-hatched condor as their own.
"These are
extraordinary events in the California condor recovery program,"
said Marc Weitzel, project leader at Hopper Mt. National Wildlife
Refuge complex near Ventura, which manages the southern California
release program. "Now, for the first time, we have a chick
hatched from wild parents, and free-flying condors that may
soon be raising a chick in the wild."
"For the first
time in 15 years, California condors are breeding in the wild,"
said Susie Kasielke, Los Angeles Zoo curator of birds. "This
is the biggest milestone for the recovery program since we began
releasing condors to the wild in 1992."
Two female condors
occupying the same nest cave produced one egg each after mating
with a single male. This is only the second time since 1982
that condors have attempted to nest in the wild, and is unusual
because two females occupy the same nest. Bruce Palmer, condor
coordinator for the U.S. Fish and Wildlife Service, was present
during the egg switch and said the most attentive female condor
returned to the nest and sat on the egg 20 minutes after it
was placed there.
The first objective
in switching eggs was to provide the wild birds the most experience
possible in proceeding through the nesting cycle. The condors
will take several breeding attempts to learn all the appropriate
behaviors to successfully raise a chick. Assisting the birds
now will greatly enhance the possibility that they can successfully
raise a chick next year. The second objective is to see a chick
raised in a truly wild setting.
On June 1 biologists from the Service, Los Angeles Zoo, and
Zoological Society of San Diego removed two eggs from the condor
nest and replaced them with a single fake egg. One of the eggs
taken from the nest was dead and the other was in danger of
dying from exposure and development complications. Scientists
believe that inexperience played a primary role in the adult
birds' confused incubation behavior as they continually switched
places in an attempt to incubate the eggs. One female condor
continued to incubate the fake egg until biologists replaced
it June 18 with an egg laid by a condor at the Los Angeles Zoo.
The three adult condors at the nest site were released to the
wild in 1995.
In moving the zoo-reared
egg to the wild, biologists waited until the embryo began to
pierce the egg's inner air cell before transporting it by helicopter
from the Los Angeles Zoo to the condor nest. When the embryo
begins this process, it takes about a week before it hatches.
"Condor parents
often help a chick out of the egg by tearing at the shell, very
gently," said Greg Austin, supervisor for the Service's
field program at Hopper Mt. National Wildlife Refuge. "Although
they're large birds, they can be very delicate when it comes
to an egg."
In 1987, the last
of 27 California condors were removed from the wild and brought
into the captive breeding program. Reintroductions to the wild
of juvenile captive-bred condors began in 1992. Condors do not
reach maturity until they are six or seven years old. This is
the first year that reintroduced condors laid eggs in the wild.
Currently, there are 34 condors in the wild in two areas in
California, and 23 free-flying condors in the Grand Canyon area
in Arizona. On March 25, 2001, the first egg laid by reintroduced
condors was discovered in the Grand Canyon by biologists working
for The Peregrine Fund, which manages the release program there.
That egg was broken by the condors and the nesting attempt failed.
There are 130 California condors being held in captivity.
Condors are scavenging
birds that soared over the Southern California mountains and
other areas since prehistoric times but their numbers plummeted
in the 20th century. The causes of their decline are not completely
known but lead poisoning is believed to be among the factors.
Condors were listed as an endangered species in 1967, under
a law that predated the existing Endangered Species Act. In
1982, the condor population reached its lowest level of 22,
prompting Service biologists to start collecting condor chicks
and eggs for a captive breeding program. By late 1984, only
15 condors remained in the wild and six of them died within
a short period, several from lead poisoning. Lead poisoning
occurs after scavenging birds such as condors, turkey vultures,
golden eagles and bald eagles eat the meat of dead animals that
contain lead fragments from bullets.
The goal of the
California Condor Recovery Plan is to establish two geographically
separate populations, one in California and the other in Arizona,
each with 150 birds and at least 15 breeding pairs.
The U.S. Fish and
Wildlife Service is the principal federal agency responsible
for conserving, protecting and enhancing fish, wildlife and
plants and their habitats for the continuing benefit of the
American people. The Service manages the 94-million-acre National
Wildlife Refuge System which encompasses more than 535 national
wildlife refuges, thousands of small wetlands and other special
management areas. It also operates 70 national fish hatcheries,
64 fishery resource offices and 78 ecological services field
stations. The agency enforces federal wildlife laws, administers
the Endangered Species Act, manages migratory bird populations,
restores nationally significant fisheries, conserves and restores
wildlife habitat such as wetlands, and helps foreign governments
with their conservation efforts. It also oversees the Federal
Aid program that distributes hundreds of millions of dollars
in excise taxes on fishing and hunting equipment to state fish
and wildlife agencies.
--FWS–
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