Effects of Winter Navigation on Waterfowl and Raptors in the St. Mary's River Area,
Abstract
Waterfowl and raptors wintering in the St. Mary's River-Whitefish Bay area were observed to determine the effects of winter navigation on these birds. Commercial shipping occurred though the winter of 1978-79, but was suspended from 15 January - 24 March 1980. About 1000 waterfowl wintered in the area with the mallard, common goldeneye, and common merganser being the most common species. The raptors seen most frequently near the river were a pair of bald eagles and an occasional snowy owl. Waterfowl and raptor behavior was affected by ship passage, with both groups largely avoiding the ship channel when shipping was in progress, but using areas in and near the channel in the absence of shipping. Direct impacts of ships on waterfowl and raptors did not appear to be acute, as avian mortality on the study area was negligeable during both winters. A potentially serious impact on the birds would be the spillage of oil or other toxic substances. Indirect or chronic impacts with were not assessed include: increased turbidity of river water, reducing duck food productivity and availability; scouring of shore vegetation reducing waterfowl reproductive habitat; ship traffic depriving eagles of critical habitat or areas which have not yet been identified as such. Keywords: Environmental impact. (kt)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1980
- Accession Number
- ADA195722
Entities
People
- R. W. Jensen
- W. L. Robinson
Organizations
- Northern Michigan University