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Vivian M. Mendenhall

Publications and source records attributed to Vivian M. Mendenhall.

5 recordsLinked to original sources
USGS1993

Losses of seabirds in gill nets in the North Pacific

Existing knowledge on high-seas and coastal gillnet fisheries known to kill seabirds in the North Pacific is summarized. Recent estimates suggest that high-seas gillnet fisheries may have taken more than 500,000 seabirds in 1990. The majority of birds taken in those fisheries were Sooty Puffinus griseus or Short-tailed P. tenuirostris shearwaters. A recent analysis of impacts of those fisheries suggests that both shearwater populations may be declining slightly, although overall populations remain large. Impacts on seabirds of gillnet fishing in coastal waters are poorly known, except in California. Incidental mortality of seabirds in coastal gillnet fisheries may be adding additional stress to populations already compromised by habitat destruction and oil spills. Local populations of Marbled Murrelets Brachyramphus marmoratus , Common Murres Uria aalge , and Japanese Murrelets Synthliboramphus wumizusume may be particularly vulnerable to coastal gillnet fisheries. United National General Assembly Resolution 44/225 called for a moratorium on high-seas gillnet fishing by 30 June 1992. Japan has complied and Korea and Taiwan will comply with the moratorium.

Conference Paper↗
USGS1983

Breeding success of barn owls (Tyto alba) fed low levels of DDE and dieldrin

The relative importance of two organochlorine pesticides in the recent reproductive failure of raptors was investigated. Captive barn owls were fed 3.0 ppm DDE and 0.5 ppm dieldrin; doses were given separately and in combination for two years. Breeding success was followed from the laying of eggs through natural incubation and rearing of young. DDE was associated with significant eggshell thinning, egg breakage, embryo mortality, and reduced production per pair. Dieldrin alone was associated with slight but significant eggshell thinning, but not with reduction of breeding success. Ecological implications of the results are discussed; it is suggested that DDE had a much more severe effect on reproduction in wild raptors than dieldrin, which contributed to their decline primarily through adult mortality.

Archives of Environmental Contamination and Toxico↗
USGS1980

Secondary poisoning of owls by anticoagulant rodenticides

Anticoagulants-compounds that prevent clotting of the blood-are extensively used for control of small mammal pests. The potential secondary hazards of 6 anticoagulant rodenticides to birds of prey were examined in this study. Whole rats or mice were killed with each anticoagulant and were fed to 1-3 species of owls. Owls died of hemorrhaging after feeding on rats killed with bromadiolone, brodifacoum, or diphacinone; sublethal hemorrhaging occurred in owls fed rats killed with difenacoum. These results demonstrate potential secondary hazards of 4 anticoagulants to avian predators. No abnormalities were observed in owls fed rats killed with fumarin and chlorophacinone

Wildlife Society Bulletin↗
USGS1979

Recovery of breeding success in a population of brown pelicans

Breeding populations of the brown pelican ( Pelecanus occidentalis ) declined during the 1960's on both east and west coasts of the United States. In 1969, colonies in South Carolina fledged an average of 0.78 young per nest (Blus et al. 1974b), and those in California only 0.004 (Anderson et al. 1975). The minimum production for population stability has been estimated to be 1.0 to 1.2 fledglings per nest (Henny 1972, Anderson et al. 1977). The South Carolina population may have decreased by as much as 80% during the previous decade (Blus 1970). Organochlorine pesticides were implicated as a cause of population decline. Eggs from South Carolina contained an average of 5.4 parts per million (ppm) of DDE (wet weight basis) in 1969, and those from California about 70 ppm wet weight (Blus et al. 1974a, Anderson et al. 1975). Shells of South Carolina brown pelican eggs were,17% thinner than normal, and those from California were 30% thinner, compared with shells of eggs laid before DDE was introduced in 1947 (Blus et al. 1974a, Anderson et al. 1975); crushed eggs were common in the colonies. DDE was the primary cause of shell thinning (Blus et al. 1971), but dieldrin was also associated with breeding failure, and both may be embryotoxic (Porter and Wiemeyer 1969, Longcore et al. 1971, Blus et al. 1974b). Brown pelicans also declined in Louisiana and Texas during this period, in association with shell thinning and relatively high organochlorine levels (Anderson and Hickey 1970, Blus et al. 1975, King et al. 1977). Eggs of pelicans in Florida, however, contained lower residues, and numbers have remained stable (Williams and Martin 1970). In 1969, the Patuxent Wildlife Research Center and Cape Romain National Wildlife Refuge initiated an intensive study of the South Carolina population. Size of the breeding colonies, production, eggshell thickness, and organochlorine residues were monitored each year. Between 1969 and 1976 organochlorines in the eggs declined gradually, reproductive success improved, and the breeding population doubled (Blus et al. 1979). We have continued to monitor the South Carolina brown pelican population. Results for 1977 and 1978 are presented here, with an evaluation of the significance and possible causes of current breeding success.

Conference Paper↗