Natural Resources, School of
Date of this Version
1998
Citation
North American Bird Bander, Vol. 23 No. 1
Abstract
The Upper MississippRi iver is an importanth abitat for migratingM allards. However,s iltationa nd development threaten the value of this habitat. We used banding data at a regionals cale to determinet he derivationa nd distributiono f Mallard recoveries in the Upper Mississippi to study whether changesi n habitato ccurringd uring1 961-1989w ere reflected in Mallard migration. The Upper Mississippi has attracted a constant proportion of recoveries from SW Saskatchewan, SE Saskatchewan, SW Manitoba and the Missouri River Basin during 1965-1989. We found no changes in Mallard recovery rates during 1965-1989 for any sex/age class banded in these breeding areas (P > 0.05), except a slight decrease for adult males banded in SW Saskatchewan (P = 0.026). The derivation of Mallard recoveries has not been stable during 1961-1989. The percent of Upper Mississippi recoveries from Missouri River Basin and Great Lakes declined, while SW Saskatchewan, SE Saskatchewan, and SW Manitoba increased. We found an unequal distributiono f recoveriesa mongU pper Mississippni avigationp ools,w hichi s probably due to differences in hunter pressure or an uneven distributiono f quality habitat. Pools 1, 7, 12, 16, 22, 24, and 25, and the area below pool 26 all contributed over 500 total recoveries during 1961-1989. Our analyses of band recoveries found no evidence of decreased Mallard use of the Upper Mississippi. Whereas Upper Mississipphi abitat may be above a criticalt hreshold level, continued degradation of backwater habitats, caused by siltation, could ultimately affect watedowl use. Biologists should continue to use regional analyses of Mallard banding recoveries as one means of monitoring changes in watedowl and habitat quality on the Upper Mississippi
Comments
This article is a U.S. government work, and is not subject to copyright in the United States.