Raptor abundance and northern bobwhite survival and habitat use

J. Turner; F. Hernandez; Clint W. Boal; Bart M. Ballard; Fred C. Bryant; D.B. Wester

doi:10.1002/wsb.476

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Raptor abundance and northern bobwhite survival and habitat use

J. Turner·F. Hernandez·Clint W. Boal·Bart M. Ballard·Fred C. Bryant·D.B. Wester

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Abstract

Predation risk has a profound influence on prey behavior and habitat use. The Rio Grande Plains ecoregion of Texas, USA, provides a unique opportunity to investigate changes in prey behavior because the ecoregion experiences a high influx of raptors every year during autumn migration. We used an 8-year data set (2000–2008) of radiocollared northern bobwhites ( Colinus virginianus ) and raptor abundance to test the hypothesis that bobwhites responded to increased raptor abundance via changes in woody-cover use at the home-range scale. Bobwhite survival was negatively correlated with raptor abundance, with red-tailed hawks ( Buteo jamaicensis ), and northern harriers ( Circus cyaneus ) accounting for 51% of the variability in bobwhite survival ( P  < 0.010). However, we documented no change in the amount of woody cover used by bobwhites in their home range between the raptor migration (6.6% ± 0.5%; n  = 73 bobwhites) and non-migration periods (7.1% ± 0.4%; n  = 105 bobwhites; P  = 0.490). In addition, bobwhites that survived the raptor migration period used similar amounts of woody cover within their home range (6.3% ± 0.6%, n  = 58 bobwhites) compared with those dying during the migration period (6.8% ± 0.4%, n  = 100 bobwhites; P  = 0.530). Our data suggest that bobwhites do not alter their use of woody cover at the home-range scale in response to increasing raptor abundance, but this does not preclude increased use of woody cover at the point-of-use scale.

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Source-reported bounding extent: 25.918526162075153° to 30.939924331023445° latitude; -101.0467529296875° to -96.1083984375° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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J. Turner, F. Hernandez, Clint W. Boal, Bart M. Ballard, Fred C. Bryant, D.B. Wester. 2014. Raptor abundance and northern bobwhite survival and habitat use. https://doi.org/10.1002/wsb.476

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