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

Dan J. Calvert, Irene M. Barry, 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.  For all color-marked birds, dispersal events occurred sooner, and estimated
dispersal probabilities were higher than in 1999.  Multiple daily observations of radio-marked
birds were determined with triangulation from 200-300 m distance from the cliff face.  We used
Global Positioning System units to determine telemetry locations, and we compiled movement
data on Arc/View.        

Keywords: peregrine falcon, Falco peregrinus, Mississippi River cliffs, dispersal, habitat use,
GIS