DISPERSAL AND HABITAT USE OF JUVENILE PEREGRINE  FALCONS  DURING  A
RESTORATION PROJECT IN DUBUQUE, IA

Dan J. Calvert and Larkin A. Powell.
Department of Biology and Environmental Science, University of Dubuque, 2000 
University Avenue, Dubuque, IA  52001.

In the largest single restoration effort in Iowa to date, 21 juvenile peregrine falcons 
were released by the Iowa Department of Natural Resources from a natural cliff near 
Eagle Point Park in Dubuque, Iowa during summer 1999.  We used radio-telemetry 
and observations of color-marked birds at the hack site to determine habitat use. 
Telemetry proved very ambiguous near the cliff site, although daily observations could 
be determined with triangulation from 200-300 m distance.  All radio-marked falcons 
shed their long-mounted radios within 1 day to 2 weeks, creating the need to find a 
new attachment method for the 2000 field season.  Falcons were released in a 
staggered manner from mid-June until late-July.  Older falcons remained at the site 
longer than at previous urban releases and interacted with the younger falcons.  Thus, 
efforts to determine post-dispersal habitat use with aerial telemetry were not possible. 
Falcons released at power plants and urban buildings throughout Iowa have not used 
cliff habitat during the juvenile year, the Dubuque falcons perched and fed on the 
cliffs.  We used Global Positioning System units to determine telemetry locations, and 
we complied habitat use data on Arc/View.

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