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At least 919 records · Page 51Linked to original sources
USGS1982

Migratory peregrine falcons, Falco peregrinus, accumulate pesticides in Latin America during winter

Blood samples from 433 Peregrine Falcons (Falco peregrinus) during fall and spring migrations, 1976-80, indicated that most of their pesticide burden, primarily DDE, was accumulated on wintering grounds in Latin America. DDE in spring migrants returning from Latin America for the first time declined significantly from 1979 to 1980. Only about 10% of breeding-age females contained organochlorine residues likely to adversely affect reproduction. The organochlorine pesticide threat in Latin America may be diminishing.

Canadian Field-Naturalist↗
USGS1982

Fall and winter homesite use by wolves in northeastern Minnesota

Post-abandonment homesite use by wolves (Canis lupus) was studied by radio-tracking and simulated howling in two packs in Superior National Forest, Minnesota. Pups, yearlings, and adults returned intermittently to former homesites up to four months after abandonment, usually after prolonged separation from the pack in early fall. Returns sometimes exceeded one week. Preferred summer homesites were revisited most frequently. Visits declined as the season progressed either because attempts to relocate the pack were not facilitated, or simply because separations became rare. While temporarily at homesites, single wolves replied significantly more to simulated howling than when anywhere else, suggesting that homesites may provide reassurance for separated wolves.

Canadian Field-Naturalist↗
USGS1983

Survival of female black ducks, Anas rubripes, during the breeding season

The Mayfield method was used to estimate the survival rate of 19 radio-marked, female Black Ducks (Anas rubripes) in southcentral Maine during 1977-80. An overall survival rate of 0.74 was estimated for the 121-day monitoring period that included the pre-laying and laying, incubation, brood rearing, and post-rearing stages. No differences in survival rates were detected among these stages. Two instrumented hens were killed by Red-shouldered Hawks (Buteo lineatus) and a third was killed by an unknown predator. We found no evidence that the attachment of radio transmitters affected hen survival.

Canadian Field-Naturalist↗
USGS1985

Areas of localized organochlorine contamination in Arizona and New Mexico

Wings from mallard ducks harvested in 1980 in Arizona, Arkansas, Louisiana, and New Mexico were pooled into county aggregates and analyzed for organochlorine pesticides and PCB's. Organochlorine concentrations in duck wings were compared among counties comprising major river drainages within each state. DDE concentrations in the wings of mallards collected from the Verde River and the lower portion of the Gila River drainages in Arizona ranged up to 6 ppm (wet weight basis), which was 17 times higher than the 1979 Pacific Flyway average. DDE at these high levels may be hazardous to wildlife. In combination with other published data, our findings indicate a serious DDT problem in portions of the Verde River and Gila River drainages. High levels of heptachlor (up to 1.7 ppm) and PCB's (3.7 ppm, 61 times the 1979 Central Flyway average) were found in mallard wings from the upper Rio Grande and Pecos River drainages, respectively. We did not detect areas of heavy local organochlorine pesticide or PCB contamination in Arkansas and Louisiana.

Southwestern Naturalist↗
USGS1980

White-faced ibis populations and pollutants in Texas, 1969-1976

Eggshell thickness, levels of pollutant residues, and population status of the white-faced ibis (Plegadis chihi) were monitored in Texas from 1969 through 1976. Texas ibis nesting populations declined by 42%. Reproductive success apparently was limited by DDE-induced shell thinning and by dieldrin-caused mortality. Eggshells averaged 4% to 10% thinner than the pre-1943 mean thickness. Shells of numerous crushed eggs exceeded 20% thinning. Mean DDE residues in randomly collected eggs decreased from 0.94 ppm in 1970 to 0.25 ppm in 1976. DDE was higher, averaging 2.5 ppm, in thin-shelled eggs. DDE was negatively correlated with shell thickness. Dieldrin and PCB residues increased slightly from 1970 to 1976, but neither was correlated significantly with shell thickness. Residues in brains of many dead and dying ibises collected during years of extreme reproductive failure, 1970 and 1973, contained between 5 and 25 ppm dieldrin. Ibises were exposed to aldrin and dieldrin by feeding in rice fields where aldrin-treated rice seed was planted. Improved nesting success in 1976 may have been related to declining residues of DDE and to the discontinued use of aldrin in rice fields.

Southwestern Naturalist↗
USGS1983

Elevated DDE and toxaphene residues in fishes and birds reflect local contamination in the lower Rio Grande Valley, Texas

A potential organochlorine pesticide problem was identified near Mission, Texas, by the National Pesticide Monitoring Program. Fish samples from this site have consistently contained elevated levels of DDE since 1968. Surveys were made in 1976, 1978, and 1979 to determine the extent of organochlorine pesticide contamination in fishes and birds of the area. Freshwater fishes of the Arroyo Colorado, a major waterway traversing the lower Rio Grande Valley, were highly contaminated with DDE and toxaphene residues compared to samples from other areas in the Valley; both DDE and toxaphene ranged up to 31.5 ppm wet weight in whole-fish composite samples. In addition, median DDE residues in fish-eating bird carcasses from this area ranged up to 34 ppm wet weight, and 81 ppm in individual specimens. The levels of contaminants detected in fishes and birds were within, or above, the range producing adverse effects in certain species. The major sources of contamination to the Arroyo Colorado system likely stem from past and present use of persistent pesticides on surrounding croplands, and possibly from an abandoned pesticide plant at Mission, Texas.

Southwestern Naturalist↗
USGS1990

Eggshell thinning and contaminant levels in bald eagle eggs from Arizona, 1977 to 1985

The mean eggshell thickness of 11 eggs of bald eagles (Haliaeetus leuccocephalus) and 21 samples of eggshell fragments (n = 32) collected from 14 nests in Arizona during 1977 to 1985 was 0.539 mm, 8.8% thinner than the pre-1947 (pre-DDT) mean for eggs from southern California and Baja California, Mexico. Eleven eggs analyzed for contaminants contained slightly elevated concentrations of DDE (3.3pmm wet weight) and mercury (0.14 ppm). Productivity of sampled pairs was low but improving. The predictive equations of Wiemeyer et al. (1984) were also verified.

Southwestern Naturalist↗