USGS - science for a changing world

Northern Prairie Wildlife Research Center

  Home About NPWRC Our Science Staff Employment Contacts Common Questions About the Site

Canvasback Duckling Mortality: The Agassiz Story

CARL E. KORSCHGEN, KEVIN P. KENOW,
AND WILLIAM L. GREEN

U.S. Fish and Wildlife Service, Northern Prairie Wildlife Research Center,
La Crosse Field Station, P.O. Box 2226, La Crosse, WI 54601


Previous studies have not identified mortality factors of young-of-the-year canvasbacks nor the full extent of duckling mortality because of the potential for loss of total broods and the breakup of broods at an early age. The goal of this investigation was to develop telemetry techniques and conduct research to determine the causes and magnitude of canvasback duckling mortality. The study was conducted at Agassiz National Wildlife Refuge (NWR) in northwestern Minnesota. Thus far, data have been collected and analyzed for three spring/summer periods, 1987-89. A total of 288 ducklings have been radio-marked. Survival rates have been calculated for each sex/year class using two methods depending upon whether birds whose transmitters failed (lost birds) were assumed to be alive or dead. Survival rates were calculated based on a total of 5,692 duckling exposure days. Most mortality occurred within the first 10 days. The primary sources of mortality over the three years were exposure and mink predation. In all three years, females had lower survival than males. Total brood loss amounted to 20%, 36%, and 22% of broods released in 1987-89, respectively.
Previous Section -- Predator Management: Success and Failure in the Devils Lake Area
Return to Contents
Next Section -- Overwater Nest Structures for Ducks and Geese

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://www.npwrc.usgs.gov/resource/birds/symabs/canvas.htm
Page Contact Information: Webmaster
Page Last Modified: Friday, 01-Feb-2013 19:59:28 EST
Sioux Falls, SD [sdww54]