DISTRIBUTION AND ABUNDANCE OF TUNDRA SWANS ON SELECTED AREAS OF THE UPPER 
MISSISSIPPI RIVER DURING FALL 2004.
 
Kevin P. Kenow1, Larry R. Robinson1, Brian R. Gray1, James M. Nissen2, and Brian 
Lubinski3 
1U. S. Geological Survey, Upper Midwest Environmental Sciences Center, La 
Crosse, WI  54603.  2U. S. Fish and Wildlife Service, Upper Mississippi River 
National Wildlife and Fish Refuge, Onalaska, WI 54601.  3U. S. Fish and Wildlife 
Service, Regional Office, Bishop Henry Whipple Federal Building, Fort Snelling, 
MN 55111  


The Upper Mississippi River (UMR) is an important stopover area for the Eastern 
Population of tundra swans (Cygnus columbianus columbianus) during fall 
migration.  Because of the increased public interest in swans and the 
responsibility for management of the UMR for this trust species, river managers 
and biologists have identified and prioritized several research needs that would 
provide important information to support the wise management of tundra swans.  A 
project was recently initiated to assess the availability of food resources and 
the impacts of tundra swans on those resources on the UMR, a primary research 
need that was identified.  

One objective of the project is to determine the distribution and abundance of 
tundra swans on selected areas of the UMR using remote sensing techniques.  
Digital aerial photography was acquired on multiple occasions during October 
through December 2004 to document numbers and distribution of tundra swans.  
Georeferenced composite imagery is then used to map the distribution of swans 
and automated counting software employed to generate an accurate count.  Here we 
provide swan distribution maps, including an interpretation of swan core use 
areas using the fixed kernel home range utilization distribution for 95% 
probability; abundance of swans by pool management areas; and link the 
information with vegetation cover data.  Seasonal change in swan distribution 
will also be illustrated.  This information should contribute to our 
understanding of swan ecology and be useful to river resource managers in the 
development and implementation of management strategies for enhancement of the 
UMR as an important resource for tundra swans.

Keywords:  Cygnus columbianus, digital imagery, survey techniques, tundra swan, 
Upper Mississippi River