Wildlife Health

Disease in amphibian populations can have a range of effects, from devastating declines following introduction of a novel pathogen to recurring breakout events on a landscape. Elucidating mechanisms underlying the effects of diseases on amphibian populations is crucial to help managers make appropriate decisions to achieve management goals for amphibians.

The Challenge: In eastern North America there is a viral disease called Eastern Equine Encephalitis, or EEE. This virus is transmitted among native bird species by the mosquito, Culiseta melanura, but does not cause disease in these passerine species. However, the virus is capable of causing severe disease or death in horses, some game bird species, humans and whooping cranes. In the fall of 1984...

The Challenge: The health of the abundant waterfowl species of Chesapeake Bay has become a major concern due to the spread of Avian Influenza (AI) across North America and the role of waterfowl as a vector of AI. For decades, the health of the Bay’s waterfowl has been affected by the degradation of water quality and food supply due to industrial contaminants,agricultural run-off, pollution from...

The Oregon spotted frog ( Rana pretiosa) is a medium-sized anuran native to the northwestern United States. Body coloration ranges from brown or tan to brick red, usually overlaid with dark, ragged spots. Oregon spotted frogs can be distinguished from other native species by their relatively short hind legs, orange or red wash of color on underside of abdomen and legs, and upturned chartreuse eyes...

This work provides basic information for managing golden eagles in the context of the Bald and Golden Eagle Protection Act (16 U.S.C. 668-668d). The recent development of energy resources, such as wind, oil, gas, and solar, can potentially affect landscapes in ways that require changes in golden eagle management practices. Our work emphasizes priority information needs identified by the USGS and U...

Many species of amphibians and reptiles are declining or facing population threats in the West related to habitat loss, habitat alteration, introduction of non-native species, and other factors. Our work focuses on the status and trends of resident herpetofauna and how to better manage their habitats. Much of the effort is undertaken with cooperators, particularly with other agencies in the...

In 2012, scientists noticed that nearly a third of polar bears sampled in a study in Alaska were suffering from hair loss and poor health. Drs. Lizabeth Bowen and A. Keith Miles of WERC used new technology to track down and identify the factors responsible for driving disease in Alaskan polar bears.

This project improves our understanding of the ecology of reptiles in California and evaluates methods of managing landscapes and these imperiled species. In particular, Dr. Brian Halstead examines the distribution and demography of reptiles to understand factors that affect where they are found and how populations change. He further explores the relationships of reptiles with their abiotic and...

California’s Central Valley and San Francisco Bay Estuary have a long history of mercury contamination from past mercury mining and gold extraction. Waterbirds are particularly susceptible to mercury because of their use of wetland habitats where methylmercury (the most toxic and biologically available form) is produced and relatively low methylmercury exposure can reduce reproductive success...

Sea otters are crucial indicators of the health of our nearshore waters and coastal resources, from kelp forests to fisheries. What clues does the sea otter's decline hold for our knowledge of ecosystem and global change? WERC's sea otter team and U.S. and Canadian researchers have teamed together to investigate. Relevance to USGS Missions: This research project has direct relevance for the...

Low-elevation Pacific islands are vulnerable to inundation from sea-level rise and sudden flooding events. The largely low-lying islands of Northwestern Hawaiian Islands (NWHI), that extend 1,930 km beyond the main Hawaiian Islands, are a World Heritage Site and part of the Papahānaumokuākea Marine National Monument. The NWHI support the largest tropical seabird rookery in the world, provide...

This assessment deals with a select geographic area, the Upper Great Lakes, and the common birds that can be found there during migration periods. Much is known about potential landbird stopover habitats and raptor migration routes, and a great deal of GIS data is available to develop preliminary risk models for landbirds. However, the distribution, abundance and species composition of waterbirds...