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A removal model for estimating detection probabilities from point-count surveys

Program for the One Hundred and Eighteenth Stated Meeting of the American Ornithologists' Union in conjunction with the 19th Annual Meeting of the Society of Canadian Ornithologists, Societe des Ornithologistes du Canada and the British Ornithologists' Union, August 14-19, 2000. OCLC: 45282415
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Abstract

We adapted a removal model to estimate detection probability during point count surveys. The model assumes one factor influencing detection during point counts is the singing frequency of birds. This may be true for surveys recording forest songbirds when most detections are by sound. The model requires counts to be divided into several time intervals. We used time intervals of 2, 5, and 10 min to develop a maximum-likelihood estimator for the detectability of birds during such surveys. We applied this technique to data from bird surveys conducted in Great Smoky Mountains National Park. We used model selection criteria to identify whether detection probabilities varied among species, throughout the morning, throughout the season, and among different observers. The overall detection probability for all birds was 75%. We found differences in detection probability among species. Species that sing frequently such as Winter Wren and Acadian Flycatcher had high detection probabilities (about 90%) and species that call infrequently such as Pileated Woodpecker had low detection probability (36%). We also found detection probabilities varied with the time of day for some species (e.g. thrushes) and between observers for other species. This method of estimating detectability during point count surveys offers a promising new approach to using count data to address questions of the bird abundance, density, and population trends.

Additional Publication Details

Publication type:
Book chapter
Publication Subtype:
Book Chapter
Title:
A removal model for estimating detection probabilities from point-count surveys
Year Published:
2000
Language:
English
Publisher:
Memorial University of Newfoundland
Publisher location:
St. John's, Newfoundland, Canada
Contributing office(s):
Patuxent Wildlife Research Center
Description:
154
Larger Work Type:
Book
Larger Work Subtype:
Other Government Series
Larger Work Title:
Living on the Edge -- Birds 2000: Abstracts
First page:
28
Last page:
29
Number of Pages:
154