To catch a (marsh) predator: Modified trapping methods for breeding and wintering Northern Harriers (Circus hudsonius)

Journal of Raptor Research
By: , and 

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Abstract

Although there are a variety of methods available for trapping raptors, some species, such as Northern Harriers (Circus hudsonius), are not easily captured with standard methods. We tested several existing trapping methods and modified two of them based on Northern Harrier ecology and behavior across seasons in a study population in California. No previously successful methods described in the literature were effective for our study population. Two modified methods were most effective for trapping Northern Harriers: (1) placing two dho-gazas around the nest in a V-shape and flushing the adult female into the nets during the breeding season, and (2) using remote-triggered bow nets baited with waterbird carcasses in winter. Dho-gazas at the nest worked well during the early nestling-rearing stage, when nestlings were younger than 2 wk old and adult females were most attentive. This method was not suitable during the incubation stage because Northern Harriers are prone to nest abandonment. In the winter, Northern Harriers are known to scavenge, yet this aspect of their behavioral ecology has previously been rarely exploited for trapping purposes. These two methods allow for selective Northern Harrier trapping across seasons and provide modified options for research on this understudied and declining species in North America.

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Publication type Article
Publication Subtype Journal Article
Title To catch a (marsh) predator: Modified trapping methods for breeding and wintering Northern Harriers (Circus hudsonius)
Series title Journal of Raptor Research
DOI 10.3356/JRR-21-79
Volume 56
Issue 2
Year Published 2022
Language English
Publisher Allen Press
Contributing office(s) Western Ecological Research Center
Description 11 p.
First page 190
Last page 200
Country United States
State California
Other Geospatial Suisun Marsh
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