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Post-precipitation bias in band-tailed pigeon surveys conducted at mineral sites

Wildlife Society Bulletin

By:
, , and
DOI: 10.2193/0091-7648(2005)33[1047:PBIBPS]2.0.CO;2

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Abstract

Many animal surveys to estimate populations or index trends include protocol prohibiting counts during rain but fail to address effects of rainfall preceding the count. Prior research on Pacific Coast band-tailed pigeons (Patagioenas fasciata monilis) documented declines in use of mineral sites during rainfall. We hypothesized that prior precipitation was associated with a short-term increase in use of mineral sites following rain. We conducted weekly counts of band-tailed pigeons at 19 Pacific Northwest mineral sites in 2001 and 20 sites in 2002. Results from regression analysis indicated higher counts ???2 days after rain (11.31??5.00% [x????SE]) compared to ???3 days. Individual index counts conducted ???2 days after rain were biased high, resulting in reduced ability to accurately estimate population trends. Models of band-tailed pigeon visitation rates throughout the summer showed increased mineral-site counts during both June and August migration periods, relative to the July breeding period. Our research supported previous studies recommending that mineral-site counts used to index the band-tailed pigeon population be conducted during July. We further recommend conducting counts >3 days after rain to avoid weather-related bias in index estimation. The design of other population sampling strategies that rely on annual counts should consider the influence of aberrant weather not only coincident with but also preceding surveys if weather patterns are thought to influence behavior or detection probability of target species.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Post-precipitation bias in band-tailed pigeon surveys conducted at mineral sites
Series title:
Wildlife Society Bulletin
DOI:
10.2193/0091-7648(2005)33[1047:PBIBPS]2.0.CO;2
Volume
33
Issue:
3
Year Published:
2005
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Wildlife Society Bulletin
First page:
1047
Last page:
1054
Number of Pages:
8