falcons in California
Kid - Photo: Glenn Stewart/SCPBRG
I was still five minutes
from my observation point when I heard the unmistakable wailing
call of a peregrine falcon. It was the unhurried, ascending wail,
waaaaa, waaaaa, of the male as he let the female know that he was
nearby as she lay atop her clutch of eggs.
I hurried along the trail
hauling the weight of a heavy tripod, 60-power scope, binoculars,
and thermarest to the edge of the canyon. I set up and soon located
the peregrine on the branch of a snag across the canyon. He was
so far away that I could see his beak open before the sound of his
wailing reached me. What a stunning sight! Black cap, white breast,
and slate gray wing all visible in the morning light.
peregrine is known to be the fastest animal on the planet.
Near vertical dives in pursuit of prey often exceed 200 mph.
Photo: David Gregoire/SCPBRG
Every three or four hours,
the male peregrine visits the female at the nest to deliver food
to her or to give her a break from incubation. This "nest exchange"
is the only opportunity observers have to pinpoint the location
of the actual nest ledge.
After a long wait, I
was rewarded by the sight of the male dropping from his perch in
an arcing dive that ended with his landing on a cliff ledge. He
bowed forward with a "chupping" call, and disappeared.
The female had already emerged and was in flight before the cliff.
But I held on the spot where the male had disappeared and carefully
noted nearby landmarks-a large, round, flat-faced rock and reddish
stain near the ledge where the male disappeared. Then I sat back
and enjoyed the female's flight. She circled in the sunshine seeming
to enjoy spreading wings and tail to gain altitude. After two or
three turns of the circle, her feet dropped and a large stream of
excreta fell away. She flew some more and then perched in the morning
sun to preen and stretch. Surely, I thought, she is on eggs.
Here is a species that
has fascinated humankind throughout the ages. The peregrine is an
extraordinarily efficient bird hunter that is known to be the fastest
animal on the planet. Near vertical dives in pursuit of prey often
exceed 200 miles per hour. "Peregrine" is Latin for "wanderer"
or "foreigner." Some peregrines that breed in the high
Arctic migrate as far as the high, central plains of Argentina for
This magnificent bird
almost became extinct because the pesticide DDT was causing eggshell
thinning and breakage. By 1970, no peregrine falcons could be found
nesting successfully east of the Mississippi River, and just two
pairs were found producing young in California.
nest in the sand and gravel found on protected ledges.
Photo: Craig Himmelwright/SCPBRG
Thanks to the elimination
of most uses of DDT and population recovery through captive breeding,
releases of young, and, management of wild pairs, the species has
recovered and been removed from the federal endangered species list.
(The state of California continues to list the peregrine as "endangered.")
The nest in the Santa
Cruz Mountains is one that I found while hiking several years ago.
It is one of 12 to 15 such nest sites in the Santa Cruz, Monterey,
San Benito, tri-county area.
Never in the past 50 years have peregrine falcons been more abundant.
It is only during the approximately 100-day breeding period (courtship
to fledging) that we can learn something about the California peregrine
falcon population by counting nesting pairs and, if possible, noting
the number of young. A database of this information has been maintained
year after year since the early 1970s.
We monitor their numbers
because fluctuations in the peregrine falcon population can be a
valuable indicator of environmental health. Site fidelity is very
high among this species, so many observers return to sites year
after year to report on occupancy and productivity. With the current
estimated California population at 300 pairs, Predatory Bird Research
Group biologists cannot begin to monitor all of them within the
breeding cycle, so we depend on the reports of volunteer observers.
The peregrine falcon
is among the most widely distributed birds in the world nesting
on every continent and major landmass except Antarctica. They nest
in the sand or gravel found on protected ledges and prefer tall
cliffs (and buildings and bridges) overlooking sea coasts, lakes,
and rivers. Many people in the Monterey area are familiar with the
"Embassy Suites" peregrines that perch on the building's
letters from October to April each year. Like other wintering peregrines
in the Bay Area, they disappear around the income tax deadline to
return to their nesting territory which is likely somewhere in the
The "Embassy Suites"
falcons are sometimes seen standing on the ventilation stacks of
the Monterey Bay Aquarium. In Santa Cruz, a wintering peregrine
is often seen perched near the mouth of the San Lorenzo River or
across from the Natural History Museum.
Glenn Stewart is Program
Manager for the UCSC Predatory Bird Research Group.
a peregrine observer
The UC Santa Cruz
Predatory Bird Research Group was central to peregrine falcon
recovery activities in California, Oregon, and Nevada from
1975 to 1992. They produced young for release from a captive
flock and from thin-shelled eggs collected in the wild for
hatching in the incubation lab. Research is continuing.
If you are interested
in participating by filing reports of peregrine falcon nesting
activity, download the observation form at www.scpbrg.org
"peregrine survey." A link is provided to a detailed
description of nesting behaviors. Using the behaviors as a
guide, observers can determine nesting chronology from a distance
so that the wild falcons are never disturbed. Observers may
contact Glenn Stewart, firstname.lastname@example.org
with information or questions.
Limited grant funds
make school assemblies on the peregrine falcon recovery available
for grades three and up. The 45-minute presentations include
slides illustrating the peregrine's natural history, biologists
at work raising young falcons, and, climbers entering cliff
nests in the wild. A tame peregrine accompanies the presenter.
Please contact Glenn Stewart, email@example.com
for more information or to schedule an assembly.
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