Publications

Double-crested cormorant (Phalacrocorax auritus) eggs were injected with either 3,3′,4,4′,5-pentachlorobiphenyl (polychlorinated biphenyl [PCB] 126; 70-698 μg/kg egg) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; 1.3-11.7 μg/kg egg) prior to incubation. These compounds were injected into the yolks of cormorant eggs collected from incomplete clutches at isolated colonies on Lake...

Northern leopard frogs (Rana pipiens) were injected intraperitoneally either with a solution of polychlorinated biphenyl (PCB) 126 in corn oil at a concentration of 0.2, 0.7, 2.3, or 7.8 mg/kg body weight or with corn oil alone. Appropriate assay conditions with hepatic microsomes were determined for four cytochrome P450-associated monooxygenases: ethoxyresorufin-O-dealkylase (EROD)...

Ault male greater scaup (Aythya marila), surf scoters (Melanitta perspicillata), and ruddy ducks (Oxyurajamaicensis) were collected from Suisun Bay and coastal Tomales Bay in the greater San Francisco Bay area to assess exposure to inorganic contaminants. Hepatic Se concentrations were highest in greater scaup (geometric mean = 67 ppm dry weight) and surf scoters (119 ppm) in Suisun Bay...

Earlier studies have reported on the toxicity and related oxidative stress of different forms of Se, including seleno- D,L-methionine, in mallards (Anas platyrhynchos). This study compares the effects of Se (seleno-D,L-methionine) and Hg (methylmercury chloride) separately and in combination. Mallard drakes received one of the following diets: untreated feed (controls), or feed...

We developed a Markov process model for colony-site dynamics of Gull-billed Terns (Sterna nilotica). From 1993 through 1996, we monitored breeding numbers of Gull-billed Terns and their frequent colony associates, Common Terns (Sterna hirundo) and Black Skimmers (Rynchops niger), at colony sites along 80 km of the barrier island region of coastal Virginia. We also monitored flooding...

This past summer. our small field team followed a 4000 km route through central and eastern Mongolia. Even though there was a population crash underway for picas (Ochotona sp.) and voles (Microtus sp.). we found 38 new saker nests and visited 60 eyries found in previous years. Many of the former eyries were unoccupied. Others were occupied but without young. Productivity was good at...

No abstract available.

No abstract available.

Backcountry campsites and shelters in Great Smoky Mountains National Park were surveyed in 1993 as part of a new impact monitoring program. A total of 395 campsites and shelters were located and assessed, including 309 legal campsites located at 84 designated campgrounds, 68 illegal campsites, and 18 shelters. Primary campsite management problems identified by the survey include: (1)...

In 1994 and 1995, Double-crested Cormorants Phalacrocorax auritus were monitored from egg-laying through 12 days of age at Cat Island, Green Bay, Wisconsin, USA. Sample eggs at hatching were analysed for organochlorines (including total PCBs, PCB congeners, and DDE), hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) activity in livers of embryos, and eggshell thickness. The number...

During the past 40 years, profound changes have occurred in the number of Canada geese (Branta canadensis) wintering in different regions of the Atlantic Flyway. To explain the declining number of wintering geese in the Chesapeake and Carolina regions and the increasing number in the mid-Atlantic region from 1984 to 1989, I tested several hypotheses concerning regional differences in...

Although Roseate Terns (Sterna dougallii) habituate to many research activities, trapping and handling breeding adults, or repeatedly handling chicks, may affect reproductive success or chick growth. Protocols for trapping adult Roseate Terns that reduce the chances of nest desertion, neglect of chicks, and injury to adults were developed in the early 1980s, but neither short-term nor...