Publications

Delphinus bairdii Dall is a species of dolphin distinct from D. delphis Linnaeus, with which it has usually been synonymized. D. bairdii has a longer rostrum relative to the zygomatic width of the skull; the ratio of these measurements falls at 1.55 or above for bairdii and 1.53 and below for delphis. In the eastern Pacific Ocean, D. bairdii is found in the Gulf of California and along the west co

Seven species of geographically variable birds have been reported as part of the resident avifauna of San Esteban Island in the Gulf of California, Sonora. Two of these, the Curvebilled Thrasher and the Blue-gray Gnatcatcher, may not actually have breeding populations there, at least at the present time. Of the seven, only two, the Verdin and the doubtfully resident thrasher, can be used in a dete

No abstract available.

Nationwide monitoring of organochlorine pesticides in wings of more than 24,000 mallards and black ducks bagged during the1965 and 1966 hunting seasons showed DDE to be the predominant residue, followed in order by DDT, DDD, dieldrin, and heptachlor epoxide. Residues were generally highest in wings from the Atlantic and Pacific Flyways, and lowest in the Central Flyway. DDE was reported for ever

No abstract available.

A cooperative research effort between the ammunition industry and the Bureau of Sport Fisheries and Wildlife is aimed at finding a suitable non-toxic substitute for lead shot. A contract study by an independent research organization evaluated ways of coating or detoxifying lead shot or replacing it with another metal. As a result of that study, the only promising candidate is soft iron. Previous t

No abstract available.

No abstract available.

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 reg

As a major part of establishing hunting regulations each year in the United States, data for the mallard ( A m platyrhymhos) 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 r

No abstract available.

It is postulated that disease is a product of adverse habitats. Overpopulation causes overutilization of food supplies, which results in malnutrition and a decrease in resistance to diseases. Examples of such ecological relationships in populations of Canada geese, California quail, red grouse, deer, rabbits, voles, mice and lemmings are presented.