U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska
Date of this Version
1937
Abstract
With the object of obtaining a current insight into the relationship of crows to waterfowl on their breeding grounds, a study was inaugurated in the spring of 1934 and continued through the nesting season of that and the following year. As originally planned, it called for field studies both in Canada and in the northern United States, but drought conditions had so drastically reduced the breeding population of ducks within our borders by the spring of 1934 that, after a futile effort to locate suitable areas in this country, plans were changed and the studies were restricted to Canadian areas in Saskatchewan and Alberta, where ducks and crows could be found in reasonable abundance and in close association.
The scenes of the studies cover three rather circumscribed areas- two in Saskatchewan and one in Alberta-and, although the writer believes that the facts revealed and the conclusions reached are reasonably accurate for these areas, no claim is made that the findings represent a cross-section of crow-waterfowl relationships throughout Canada. As a matter of fact the results obtained in the two areas in Saskatchewan clearly show that there may be great variation in the degree of pressure exerted by the crow at points only 50 miles apart. Much less can the results be construed as representative of what takes place in the Northern States of this country, where as yet there is a lack of adequate information regarding "average" conditions on duck-nesting grounds.
By reason of the character of the nesting environment found and the observed density of the crow population, the areas at Waterhen Lake, Saskatchewan, and the lake region to the southeast of Edmonton, Alberta, presented conditions highly conducive to crow attack upon nesting ducks; in the pot-hole region about Prince Albert, Saskatchewan, the relationship was much less acute.
Comments
Published by the United States Department of Agriculture in Circular No. 433 (1937) 40 p.