Abstract Wildfires and invasive species have caused widespread changes in western North America’s shrub-steppe landscapes. The bottom–up consequences of degraded shrublands on predator ecology demography remain poorly understood. We used a before–after paired design to study whether Golden Eagle (Aquila chrysaetos) diet nestling survivorship changed following wildfires southwestern Idaho, USA. ...

Wintering raptor populations were monitored between 1983 and 1988 in a 35 km2 study area centered 8 km north-northeast of the city of Boulder, Colorado. Raptors congregated around active prairie dog (Cynomys sp.) colonies. Golden eagles (Aquila chrysaetos) , ferruginous hawks (Buteo regalis), and red-tailed hawks (Buteo jamaicensis ) were observed hunting and capturing prairie dogs. Bald eagles...

Interspecific interactions are often difficult to elucidate, particularly with large vertebrates at large spatial scales. Here, we describe a methodology for estimating interspecific interactions by combining stable isotopes with bioenergetics. We illustrate this approach by modeling the population dynamics and species interactions of a suite of vertebrates on Santa Cruz Island, California, USA...

Apparent competition is the process by which one prey species may indirectly cause the decline in another species by sustaining a common predator. I argue apparent competition caused Sierra Nevada bighorn sheep (Ovis canadensis californiana) and Channel Island fox (Urocyon littoralis) population declines in the mid-1990s. In the Sierra Nevada, mountain lions (Puma concolor) are believed to have...

We estimate that from 500 million to possibly over 1 billion birds are killed annually in the United States due to anthropogenic sources including collisions with human-made structures such as vehicles, buildings and windows, power lines, communication towers, and wind turbines; electrocutions; oil spills and other contaminants; pesticides; cat predation; and commercial fishing by-catch. Many o...

Throughout the world, populations of scavenger birds are declining rapidly with some populations already on the brink of extinction. Much of the current research into the factors contributing to these declines has focused on exposure to drug residues, lead, and other toxins. Despite increased monitoring of these declining populations, little is known about infectious diseases affecting scavenge...

We isolated and characterized the eagle gene, encoding a member of the steroid receptor superfamily in Drosophila. In the central nervous system eagle RNA was expressed in a limited number of cells. During stages 10 and 11, eagle RNA expression was observed in four neuroblasts, NB2-4, NB3-3, NB6-4 and NB7-3. Except for NB6-4, eagle RNA expression reached a maximum at the very beginning of expre...