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Full-Text Articles in Ornithology

Predicting Nesting Habitat Of Northern Goshawks In Mixed Aspen-Lodgepole Pine Forests In A High-Elevation Shrub-Steppe Dominated Landscape., Robert A. Miller, Jay D. Carlisle, Marc J. Bechard, Dena Santini Apr 2013

Predicting Nesting Habitat Of Northern Goshawks In Mixed Aspen-Lodgepole Pine Forests In A High-Elevation Shrub-Steppe Dominated Landscape., Robert A. Miller, Jay D. Carlisle, Marc J. Bechard, Dena Santini

Robert Miller

We developed a habitat suitability model for predicting nest locations of breeding Northern Goshawks (Accipiter gentilis) in the high-elevation mixed forest and shrub-steppe habitat of south-central Idaho, USA. We used elevation, slope, aspect, ruggedness, distance-to-water, canopy cover, and individual bands of Landsat imagery as predictors for known nest locations with logistic regression. We found goshawks prefer to nest in gently-sloping, east-facing, non-rugged areas of dense aspen and lodgepole pine forests with low reflectance in green (0.53 - 0.61 μm) wavelengths during the breeding season. We used the model results to classify our 43,169 hectare study area into nesting suitability categories: …


A Study Of Mexican Free-Tailed Bat Chirp Syllables: Bayesian Functional Mixed Modeling Of Nonstationary Time Series Data With Time-Dependent Spectra, Josue G. Martinez, Kirsten M. Bohn, Raymond J. Carroll, Jeffrey S. Morris Feb 2013

A Study Of Mexican Free-Tailed Bat Chirp Syllables: Bayesian Functional Mixed Modeling Of Nonstationary Time Series Data With Time-Dependent Spectra, Josue G. Martinez, Kirsten M. Bohn, Raymond J. Carroll, Jeffrey S. Morris

Jeffrey S. Morris

We describe a new approach to analyze chirp syllables of free-tailed bats from two regions of Texas in which they are predominant: Austin and College Station. Our goal is to characterize any systematic regional differences in the mating chirps and assess whether individual bats have signature chirps. The data are analyzed by modeling spectrograms of the chirps as responses in a Bayesian functional mixed model. Given the variable chirp lengths, we compute the spectrograms on a relative time scale interpretable as the relative chirp position, using a variable window overlap based on chirp length. We use 2D wavelet transforms to …


Influence Of Latitude On The Winter Abundance Of Red-Tailed Hawks (Buteo Jamaicensis) And American Kestrels (Falco Sparverius) In Illinois, Given Harper, Anna Groves, Vic Berardi, Paul Sweet, Jance Sweet, Angelo P. Capparella Dec 2012

Influence Of Latitude On The Winter Abundance Of Red-Tailed Hawks (Buteo Jamaicensis) And American Kestrels (Falco Sparverius) In Illinois, Given Harper, Anna Groves, Vic Berardi, Paul Sweet, Jance Sweet, Angelo P. Capparella

Given Harper

We use five years of data from 18 routes surveyed to determine the temporal stability of a first reported 100 years pattern, and reconfirmed that the abundance of winter 50 years ago tailed Hawk and American Kestrel decreases with increasing latitude, being more high in the central regions of Illinos in the northern regions. Trained volunteers conducted sampling ( n  = 143) a month driving along selected routes from December to February, from 2004-2005 to 2008-2009. We found significant increases in the abundance of both species from the northern regions to the central regions of Illinois. No significant effects of …


Melanistic Adult Male Northern Harrier Wintering In Idaho, Robert A. Miller, Neil Paprocki, Elizabeth H. Urban Dec 2012

Melanistic Adult Male Northern Harrier Wintering In Idaho, Robert A. Miller, Neil Paprocki, Elizabeth H. Urban

Robert Miller

Field observation of a Northern Harrier with rare aberrant plumage.