SURVIVAL OF JUVENILE PEREGRINE FALCONS DURING A RESTORATION PROJECT
IN DUBUQUE, IA.

Irene M. Barry, Dan J. Calvert, and Larkin A. Powell.  
Department of Biology, Environmental Science Program, University of Dubuque, Dubuque, IA
52001.

As part of the Iowa Department of Natural Resource's largest single restoration effort in Iowa to
date, we monitored 17 juvenile peregrine falcons (Falco peregrinus) during summer 2000.  The
restoration site was a natural cliff near Eagle Point Park in Dubuque, Iowa.   We used
radio-telemetry and observations of color-marked birds at the hack site to estimate weekly
survival rates.  Falcons were released in a staggered manner from mid-June until late-July.  We
attached dual-cycle transmitters to 4 juveniles, and 3 radios remained on the birds at the time
they left the site.  Only 1 of the 17 juveniles died, from an electrocution on a nearby electrical
line.  Weekly survival rates were 0.988 (SE = 0.01), and the weekly resighting probability was
0.885 (SE 0.03).  We will use aerial telemetry to attempt to relocate these returning birds in
spring 2001.  Prior concerns about great-horned owl predation were unfounded at this release
site, as no mortalities were attributed to these predators although substantial numbers of owls
were seen in summer 2000.

Keywords: peregrine falcon, Falco peregrinus, Mississippi River cliffs, dispersal, survival