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Detection probability of cliff-nesting raptors during helicopter and fixed-wing aircraft surveys in western Alaska

Journal of Raptor Research

By:
, , , , and
DOI: 10.3356/JRR-09-70.1

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Abstract

We conducted repeated aerial surveys for breeding cliff-nesting raptors on the Yukon Delta National Wildlife Refuge (YDNWR) in western Alaska to estimate detection probabilities of Gyrfalcons (Falco rusticolus), Golden Eagles (Aquila chrysaetos), Rough-legged Hawks (Buteo lagopus), and also Common Ravens (Corvus corax). Using the program PRESENCE, we modeled detection histories of each species based on single species occupancy modeling. We used different observers during four helicopter replicate surveys in the Kilbuck Mountains and five fixed-wing replicate surveys in the Ingakslugwat Hills near Bethel, AK. During helicopter surveys, Gyrfalcons had the highest detection probability estimate (p^;p^ 0.79; SE 0.05), followed by Golden Eagles (p^=0.68; SE 0.05), Common Ravens (p^=0.45; SE 0.17), and Rough-legged Hawks (p^=0.10; SE 0.11). Detection probabilities from fixed-wing aircraft in the Ingakslugwat Hills were similar to those from the helicopter in the Kilbuck Mountains for Gyrfalcons and Golden Eagles, but were higher for Common Ravens (p^=0.85; SE 0.06) and Rough-legged Hawks (p^=0.42; SE 0.07). Fixed-wing aircraft provided detection probability estimates and SEs in the Ingakslugwat Hills similar to or better than those from helicopter surveys in the Kilbucks and should be considered for future cliff-nesting raptor surveys where safe, low-altitude flight is possible. Overall, detection probability varied by observer experience and in some cases, by study area/aircraft type.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Detection probability of cliff-nesting raptors during helicopter and fixed-wing aircraft surveys in western Alaska
Series title:
Journal of Raptor Research
DOI:
10.3356/JRR-09-70.1
Volume
44
Issue:
3
Year Published:
2010
Language:
English
Contributing office(s):
Forest and Rangeland Ecosystem Science Center
Description:
13 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Raptor Research
First page:
175
Last page:
187
Country:
United States
State:
Alaska