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1 September 2009 Human-Related Threats to Urban Raptors
Stephen B. Hager
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Annual bird mortality in the United States from anthropogenic sources is estimated at one billion. Urban raptors are affected by many of these factors; however, little is known about the relative frequency and magnitude of sources within and among species. I reviewed 86 published sources on mortality and urban use for the raptors of the United States and Canada. Within the Falconiformes (28 urban species), vehicle collisions and electrocutions were reported for most species (73% and 48%, respectively), and vehicular and window strikes were the leading sources of mortality for 39% and 12% of species, respectively. For the Strigiformes (14 urban species), vehicular (63%) and window (47%) collisions affected most species, and the primary sources of mortality were from vehicles (32%) and electrocution (5%). Window-strike mortality was reported for 45% of urban raptors and represented the leading source of mortality for Sharp-shinned Hawks (Accipiter striatus), Cooper's Hawks (A. cooperii), Merlins (Falco columbarius), and Peregrine Falcons (F. peregrinus). Mortality by electrocutions was also observed for 45% of the species. Collisions with vehicles affected a large proportion of urban and nonurban raptors, both for species that use roadways for various activities (e.g., foraging) and for those that do not use roadways. Overall, the literature suggested that collisions and electrocutions are important sources of mortality for most raptors. Future work should directly assess the consequences of these sources on life history and demography of raptor populations.

Stephen B. Hager "Human-Related Threats to Urban Raptors," Journal of Raptor Research 43(3), 210-226, (1 September 2009).
Received: 25 August 2008; Accepted: 1 May 2009; Published: 1 September 2009
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