Life Sciences Commons^™

Flushing Responses Of Golden Eagles (Aquila Chrysaetos) In Response To Recreation, Robert J. Spaul, Julie A. Heath

Biology Faculty Publications and Presentations

Disturbance because of human activity, including recreation on wildlands, can affect bird behavior which in turn can reduce breeding success, an important consideration for species of management concern. We observed Golden Eagles (Aquila chysaetos) during the breeding season to determine whether the probability of flushing was affected by the type of recreationist, distance to encounter, eagle nest attendance, or date. We monitored eagles in 23 nesting territories from distant (600-1,200 m) observation points and recorded recreation activity within 1,200 m of eagles in the Owyhee Front of southwestern Idaho. In most (86%, n = 270) encounters, eagles did …

Variable Shifts In The Autumn Migration Phenology Of Soaring Birds In Southern Spain, Micah N. Scholer, Beatriz Martín, Miguel Ferrer, Alejandro Onrubia, Marc J. Bechard, Greg S. Kaltenecker, Jay D. Carlisle

Biology Faculty Publications and Presentations

While alteration of the migratory habits of birds is widely regarded as one of the most evident ecological effects of climate change, studies reporting shifts in migration phenology for long-lived, long-distance migrants have been few. Using time series of count data collected in southern Spain during autumn migration, we examined the magnitude and direction of phenological shifts for six common species of soaring birds. Many current methods for investigating phenological change rely on continuous data sets; however, these data may be unavailable for a variety of reasons. We used a cross-correlation analysis, which allowed us to compare recent data on …

Movements Of A Juvenile Crowned Eagle (Harpyhaliaetus Coronatus) Tracked By Satellite Telemetry In Central Argentina, Vicente Urios, Maria Pilar Donat-Torres, Marc J. Bechard, Miguel Ferrer

Biology Faculty Publications and Presentations

Background: A juvenile Crowned Eagle was tagged at its nest with a satellite transmitter. The Crowned Eagle (Harpyhaliaetus coronatus) is one of the most unknown raptor species from the American continent. Their current distribution ranges from central Brazil to central Argentina, with a total population of 350–1500 individuals across this large area, being thus largely fragmented.

Results: During the three years of tracking the bird concentrated its movements in a range spanning for 12845 km², but concentrating mainly in four smaller areas accounting for 3073 km². The locations were recorded mainly over shrubland habitats …

Intrafeather And Intraindividual Variation In The Stable-Hydrogen Isotope (Δd) Content Of Raptor Feathers, Adam D. Smith, Kara Donohue, Alfred M. Dufty Jr.

Biology Faculty Publications and Presentations

Stable-hydrogen isotope ratios (deuterium:protium; δD) in feathers enable researchers to evaluate patterns of avian movement and to estimate the source areas of migratory birds. However, variation in feather δD remains inadequately described, thus confounding inferences of avian movement and origin. We assessed variation within a feather and among feathers within and between tracts in three species of immature raptors. Within contour feathers, measurements of δD increased from a distal section to an adjacent, proximal section; the magnitude of δD increase varied with raptor species. Furthermore, contour and flight feathers differed systematically in their δD content. Two explanations for intrafeather and …