Purpose
To return the Peregrine falcon to its natural habitat on the cliffs of the
Mississippi River and its tributaries.
Personnel
Robert Anderson, Raptor Resource Project Director
John Dingley, Raptor Resource Project Member
Dave Kester, Raptor Resource Project Member
Location
Effigy Mounds National Monument, Allamakee County, Iowa.
History and Detail
Nine falcons were released from Hanging Rock at Effigy Mounds National
Monument. Eight peregrines (four males and four females) were captively produced
by the Raptor Resource Project and one was rehabilitated from a Raptor Resource
Project nest box in Minneapolis, Minnesota. Five of the nine peregrines
released from Effigy Mounds were raised inside a natural eyrie constructed of
wood, stone, and pea gravel. This chamber was built in an attempt to imprint
Peregrines to nest on cliff face. Although Peregrines are successfully nesting
in much of the United States, the population in the Midwestern and eastern
United States is almost entirely urban/industrial. Research and experience led
us to believe that nest-site imprinting was and is playing an important role in
determining nest-site selection; therefore, the chamber was built to resemble a
cliff in the belief that birds raised inside the chamber will select cliff face
to nest on as adults. The hack began on July 18th, 1998, when the five
Peregrines raised in the natural eyrie were put into one of two hack boxes. Four
more Peregrines were added to the hack site on July 22nd. The young Peregrines
roosted around the boxes following the first few days of the release. After one
week on the wing, they gathered at the site in the evening, but roosted
elsewhere. Two females and two males were wearing tarsus mounted 30-day
two-stage lithium-powered transmitters held on with cotton thread, designed to
fall off. Once on wing, the young Peregrines moved up and down the valley almost
immediately. After one week, the Peregrines were ranging across the river to the
Wisconsin side. By the middle of August, observers had witnessed Peregrines
chasing away Osprey and taking birds in flight. Fortunately, there was not much
need to track the young falcons with telemetry as, each evening, all falcons
were accounted for. Telemetry did tell us when the young birds began to wander
from the hack site. On August 20th, John Dingley, Bob Anderson, and raptor
biologist Bob Chapman placed the quail at the hack site and then retreated to
the observation point. Within a very short time, eight individual falcons were
observed feeding on the hack boards. This was a full 33 days after release of
the first five falcons and 29 days after releasing the second group. Our
observation of eight of the nine released falcons alive and well after a month
on the wing confirmed that this Mississippi River cliff release was a huge
success.
General Evaluation of the Site
Hanging Rock is a small cliff protruding from the top of the Mississippi
River valley, some 450' above the river below. Overlooking the entire river
valley, Hanging Rock served as a prominent landmark for wayward falcons on their
early flights, preventing falcons from becoming lost. This hack site is also in
the immediate vicinity of many of the historical cliffs where the Peregrine once
nested in Minnesota, Wisconsin, and Iowa. The surrounding mature forest
throughout the park is not ideal habitat for the Great Horned Owl. Park Manager
Rodney Rolvang surveyed for owls during the owl-breeding season prior to the
release. He located a single owl out on the islands in the River and another
single bird a few miles to the north. The scarcity of owls confirmed that Great
Horned Owl predation should not be a limiting factor at this site.
Recommendations In accordance with Dr. Tom Cade's advice in Cade's "Guide
to Management of Peregrine Falcons at the Eyrie", we believe the time has
come to translocate young falcons produced in Project nest boxes located at
power plants. Our plan is to obtain the required permits to transplant 10-15
young falcons to the cliff release site. Based on past experience, we can safely
hack young birds at a site for two years before returning alumni become
aggressive towards new releases, forcing the shut down of the release site. For
this reason, we should make every effort to see that 1999's release includes as
many falcons as is possible.
Unusual Incidents
There were really no unusual incidents to speak of, although it is worth
mentioning that a mosquito hatch four days after the release left hack site
personnel drained nearly dry. At first we started applying natural repellents
but quickly switched to 100% Deet. Even then, we experienced tremendous losses
of blood.
Acknowledgements
There are many people who participated in release, but the Raptor Resource
Project would like to acknowledge in particular John Dingley and Dave Kester.
Without their boundless enthusiasm and energy, this release would not have
happened. John and Dave spent many hours building the natural eyrie, attending
the hack, and observing and feeding birds. The Raptor Resource Project would
also like to acknowledge Kate Miller and Rodney Rolvang at the National Park
Service, Pat Schlarbaum and Lowell Washburn of the Iowa DNR for support and
participation, and Northern States Power Company for its financial support.
Amy Ries
Raptor Resource Project
http://www.salamander.com/~rrp
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