title: Estimating Raptor Nesting Success: Old and New Approaches.
abstract: Studies of nesting success can be valuable in assessing the status of raptor populations, but differing monitoring protocols can present unique challenges when comparing populations of different species across time or geographic areas. We used large datasets from long-term studies of 3 raptor species to compare estimates of apparent nest success (ANS, the ratio of successful to total number of nesting attempts), Mayfield nesting success, and the logistic-exposure model of nest survival. Golden eagles (Aquila chrysaetos), prairie falcons (Falco mexicanus), and American kestrels (F. sparverius) differ in their breeding biology and the methods often used to monitor their reproduction. Mayfield and logistic-exposure models generated similar estimates of nesting success with similar levels of precision. Apparent nest success overestimated nesting success and was particularly sensitive to inclusion of nesting attempts discovered late in the nesting season. Thus, the ANS estimator is inappropriate when exact point estimates are required, especially when most raptor pairs cannot be located before or soon after laying eggs. However, ANS may be sufficient to assess long-term trends of species in which nesting attempts are highly detectable.
authors.affiliation: Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno/MS 436, Reno, NV 89557, USA.
authors.forename: Jessi L
authors.initials: JL
authors.lastname: Brown
authors.affiliation: Owyhee Desert Studies, 18109 Briar Creek Road, Murphy, ID 83650, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Steenhof
authors.affiliation: U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Snake River Field Station, Boise, ID 83706, USA.
authors.forename: Michael N
authors.initials: MN
authors.lastname: Kochert
authors.affiliation: Department of Biology, Boise State University, 1910 University Drive, Boise, ID 83725, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Bond
keywords: American kestrel; Aquila chrysaetos; Falco mexicanus; Falco sparverius; golden eagle; nest survival; nesting success; population monitoring; prairie falcon; raptors