Killing Barred Owls to Help Spotted Owls I: A Global Perspective

@inproceedings{Livezey2010KillingBO,
  title={Killing Barred Owls to Help Spotted Owls I: A Global Perspective},
  author={Kent B. Livezey},
  year={2010}
}
  • K. Livezey
  • Published 17 August 2010
  • Environmental Science
Abstract Barred Owls (Strix varia) expanded their range to include western North America and have been competing with federally threatened Northern Spotted Owls (S. occidentalis caurina) for the past few decades. To help protect Spotted Owls, the US Fish and Wildlife Service is considering conducting a 3- to 10-y study in which as many as 2150 to 4650 Barred Owls would be killed and, possibly, conducting long-term management of Barred Owls. To help give these considerations a global perspective… 
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References

SHOWING 1-10 OF 115 REFERENCES
The Invasion of Barred Owls and its Potential Effect on the Spotted Owl: a Conservation Conundrum
TLDR
Both theory and empirical information suggest that barred owls are likely to have negative effects on spotted owl range and density, but the degree of the impact is not predictable.
DOES THE PRESENCE OF BARRED OWLS SUPPRESS THE CALLING BEHAVIOR OF SPOTTED OWLS?
TLDR
A test of behavioral dominance was conducted by assessing responsiveness of Spotted Owls to conspecific calls when they were in the simulated presence (i.e., imitation of Barred Owl vocalizations) of a Barred Owls.
A synopsis of suggested approaches to address potential competitive interactions between Barred Owls (Strix varia) and Spotted Owls (S. occidentalis)
TLDR
It is believed the consequences of the invasion of Barred Owls are potentially dire for the Spotted Owl and that research and management actions are required to inform the near- and long-term decision-making process for conservation of Spotted Owls.
BARRED OWL HABITAT AND PREY: A REVIEW AND SYNTHESIS OF THE LITERATURE
ABSTRACT Barred Owls (Strix varia) historically inhabited the forests of eastern North America. During the last century, they expanded their range to include forests throughout the southern provinces
RECENT RECORDS OF HYBRIDIZATION BETWEEN BARRED OWLS (STRIX VARIA) AND NORTHERN SPOTTED OWLS (S. OCCIDENTALIS CAURINA)
TLDR
The small number of F1 hybrids detected during many years of extensive banding studies of Spotted Owls suggests that the isolating mechanisms that separate Barred and Spotted owls are normally sufficient to avoid hybridization between them.
Spatial refugia and the coexistence of a diurnal raptor with its intraguild owl predator
TLDR
Overall, kites responded to predation risk through predator spatial avoidance, being concentrated in interstitial predationrefugia bordering the core home range of owl pairs, and kite density and productivity were related to a complex interaction of IGP risk and food abundance, and were probably shaped by a mixture of top-down and bottom-up effects.
Overabundance: An Issue for Conservation Biologists?
TLDR
During the past century, the populations of many native species that are generalists or opportunists have increased, and their distributions have expanded.
Iverson (2004) on Spotted Owls and Barred Owls: Comments on methods and conclusion
TLDR
The late W.F. Iverson concluded that Spotted Owl reproductive success was unaffected by Barred Owl presence, but used statistical analysis procedures that rendered the conclusion questionable and the sample size was too small to compare reliably against the chi-square distribution.
ARE BARRED OWLS DISPLACING SPOTTED OWLS?
Abstract Barred Owls (Strix varia) have expanded their range into the Pacific Northwest, and anecdotal evidence suggests that they may be displacing the federally threatened Northern Spotted Owl
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