Charles J. Henny (Former Employee)

Breeding density, food, nesting success, and mortality of 20 bird species were monitored at Beaverhead National Forest, Montana, in 1975 in conjunction with experimental applications of trichlorfon (Dylox) and carbaryl (Sevin-4-oil) to western budworms (Choristoneura occidentalis). Bird species on nine 350- to 550-ha forested plots (three controls and three treated with each pesticide)...

The possible harmful effect of insecticides on nontarget organisms should be a prominent concern in all attempts to control forest pests. Although all wildlife must be considered, birds are particularly vulnerable. The study reported here was part of the effort to find an environmentally safe method to control one of the major sources of insect damage to forest trees - the Douglas-fir...

Brain cholinesterase activities were determined in passerines collected from northwestern forests that had been sprayed with trichlorfon, acephate, and carbaryl at 0.56, 1.13 and 2.26 kg/ha. Trichlorfon and carbaryl inhibited cholinesterase activity slightly in only a few birds, primarily canopy dwellers. In contrast, acephate caused marked inhibition of cholinesterase activity in nearly...

An estimated 810 ± 55 pairs (minimum estimate) of ospreys (Pandion haliaetus) were nesting in the study area during our survey (24 March-1 April 1977). Approximately 174 pairs nested along the Pacific side of Baja California, 255 pairs along the gulf side, 187 pairs on the Midriff Islands, and 194 pairs in coastal Sonora and Sinaloa. Most nested on cliffs adjacent to the sea (59%); some...

Many raptorial species in the Pacific Northwest have not been studied from the viewpoint of pollutant contamination. The Swainson's Hawk (Buteo swainsoni) is particularly interesting because of its highly migratory characteristic; it apparently winters primarily in Argentina (Brown and Amadon 1968, Houston 1968). White and Cade (1977) and others have suggested Central America and South...

Published records of Bald Eagles (Haliaeetus leucocephalus) nesting in Baja California during the last 50 years are nonexistent to our knowledge, and few records exist prior to that time. Friedmann et al. (1950:61, Pac. Coast Avifauna 29) describe the distribution of Bald Eagles in Baja California as "a scattering of pairs on both the Pacific and Gulf Sides." Nesting Bald Eagles were...

An estimated 355± 40 pairs (95 percent C.I.) of Ospreys (Pandion haliaetus carolinensis) nested in the northern California survey area in 1975. Eighty-one pairs were estimated along the extreme northern coast in Del Norte and Humboldt Counties. One hundred and forty-four pairs were estimated along California's northern coast in Mendociuo, Sonoma, and Marin Counties. The northern interior...

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No abstract available.

An estimated 233 + 16 (95% C.I.) pairs of ospreys (Pandion haliaetus) nested in coastal New Jersey, Delaware, Maryland, and Virginia in 1975. The present populations were considerably smaller than those reported for selected locations at the turn of the century in these four states. The New Jersey population has continued to decline during the last 25 years, although it showed some signs...

Osprey populations were studied throughout North America during the last decade as a result of dramatic declines reported along the North Atlantic Coast in the1950s and early 1960s. Researchers used banding, localized studies, aerial surveys, and pesticide analyses to identify factors influencing regional populations. Declining populations showed extremely poor production, contamination...