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Geology topics

A. D. Geis

Publications and source records attributed to A. D. Geis.

At least 37 records · Page 2Linked to original sources
USGS1969

Establishing hunting regulations and allowable harvest of mallards in the United States

As a major part of establishing hunting regulations each year in the United States, data for the mallard ( Anas platyrhynchos ) are examined extensively to estimate the effect of various harvest strategies on the breeding population the following spring. This requires estimates of the breeding-population level and of the production, harvest, and mortality rates. Predictions made at the time hunting regulations are established have been in general agreement with more reliable estimates made after the hunting season when data from banding, kill, and wing surveys are available.

Journal of Wildlife Management↗
USGS1969

Effect of restrictive hunting regulations on canvasbacks and redhead harvest rates and survival

Because of low population levels, there were especially restrictive hunting regulations between 1958-1965, including complete closures during the 1960-1963 seasons, for canvasback ( Aythya valimeria ) and redhead ( A. americana ) ducks. Banding data from 1952 through 1965 indicated that restrictive regulations reduced both harvest and annual mortality rates. During the period with very restrictive regulations, annual mortality-rate estimates ranged from 14 to 21 percent, much lower than before this period when estimates were 50 percent or higher.

Journal of Wildlife Management↗