Fall migration habitat used by canvasbacks and redheads : North and South Dakota 1958-1959 / Jerome H. Stoudt and Edward G. Wellein.

Intensive ground studies conducted in Canada the past few years indicated a general downward trend in canvasback and redhead production beginning during the 1957 breeding season. These two species and the ruddy duck are over-the-water nesters and, therefore, the first to suffer when drough conditions occur in the prairies of Canada and the United States. As a result of these studies considerable concern was expressed over the status of canvasbacks and redheads. This concern resulted in reducing the bag limit to two birds per day in 1958 and one bird per day in 1959 in an effort to reduce the kill on these two species. Because of inherent difficulties in species management, based on the ability of hunters to identify waterfowl, the possibility was recognized that this measure alone may not be adequate to manage canvasbacks and redheads on a long-term basis. This would be especially true in face of increased hunted pressure which is almost certain to occur.