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Northern goshawk monitoring in the western Great Lakes bioregion

Journal of Raptor Research

By:
, , and
https://doi.org/10.3356/JRR-10-52.1

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Abstract

Uncertainties about factors affecting Northern Goshawk (Accipiter gentilis) ecology and the status of populations have added to the challenge of managing this species. To address data needs for determining the status of goshawk populations, Hargis and Woodbridge (2006) developed a bioregional monitoring protocol based on estimating occupancy. The goal of our study was to implement this protocol and collect data to determine goshawk population status in the western Great Lakes (WGL) bioregion, which encompasses portions of Minnesota, Wisconsin, and Michigan, and is a mixture of private and public property. We used 366 goshawk nest locations obtained between 1979 and 2006 throughout the WGL bioregion to develop a model of landscape use consisting of forest canopy cover and land-cover covariates. We then used the model to develop a stratified sampling design for selecting 600-ha Primary Sampling Units (PSUs) to survey for goshawks. Project collaborators surveyed 86 PSUs for goshawk presence using broadcasted calls twice between mid-May and mid-August 2008, and recorded 30 goshawk detections in 21 different PSUs. Seventy-four percent of detections occurred at call stations with canopy closure >75%. Goshawk detection probabilities were 0.549 ± 0.118 (standard error) for the first visit to PSUs and 0.750 ± 0.126 for the second visit. We estimated the proportion of PSUs occupied by goshawks as 0.266 ± 0.047, which corresponded to 5184 ± 914 PSUs occupied by goshawks in our study area and suggested that goshawks are widely, but sparsely, distributed throughout the WGL bioregion.

Study Area

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Northern goshawk monitoring in the western Great Lakes bioregion
Series title:
Journal of Raptor Research
DOI:
10.3356/JRR-10-52.1
Volume:
45
Issue:
4
Year Published:
2011
Language:
English
Publisher:
The Raptor Research Foundation
Contributing office(s):
Coop Res Unit Leetown
Description:
14 p.
First page:
290
Last page:
303
Country:
United States
State:
Michigan, Minnesota, Wisconsin
Other Geospatial:
western Great Lakes
Online Only (Y/N):
N
Additional Online Files (Y/N):
N