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Global Change Master Directory (GCMD)
DOBSERV - A Double-observer Approach for Estimating Detection Probability and Abundance from Avian Point Counts
Entry ID: USGS_DOBSERV


Summary
Abstract: Although point counts are frequently used in ornithological studies, basic assumptions about consistency in detection probabilities often remain untested. We apply a double-observer approach developed to estimate detection probabilities for aerial surveys (Cook and Jacobson 1979) to avian point counts. At each point count, one observer is designated "primary", and indicates to the other ("secondary") observer all birds detected. The secondary observer records all detections of the primary observer, as well as any birds not detected by the primary observer. Observers alternate primary and secondary roles during the course of a survey. The approach permits estimation of observer-specific detection probabilities and bird abundance. We developed a set of models incorporating different assumptions about sources of variation (e.g., observer, bird species) in detection probability. Single observer point counts generally miss varying proportions of the birds actually present, as observer and bird species were both found to be relevant sources of variation in detection probabilities. However, using the double observer approach, overall detection probabilities (probability of being detected by at least 1 of the 2 observers) were very high (>0.95) yielding precise estimates of avian abundance. We believe that most questions meriting the effort required to carry out point counts also merit serious attempts to estimate detection probabilities associated with the counts. The double-observer approach is a method which can be used for this purpose.

Related URL
Link: DOWNLOAD SOFTWARE
Description: Download the DOBSERV software


Link: VIEW RELATED INFORMATION > USER'S GUIDE
Description: Access the DOBSERV documentation.

ISO Topic Category
BIOTA
ENVIRONMENT


Access Constraints
None


Keywords
Statistical Analysis
Estimation
Models
Bird Species
Bird Abundance


Personnel
ANDERSON H. HINES
Role: TECHNICAL CONTACT
Phone: 443-482-2208
Email: hines at serc.si.edu
Contact Address:
Smithsonian Environmental Research Center
P.O. Box 28
647 Contees Wharf Road
City: Edgewater
Province or State: Maryland
Postal Code: 21037
Country: USA


ORNL DAAC USER SERVICES OFFICE
Role: SERF AUTHOR
Phone: 1-865-241-3952
Email: uso at daac.ornl.gov
Contact Address:
ORNL DAAC User Services Office
Oak Ridge National Laboratory
City: Oak Ridge
Province or State: TN
Postal Code: 37831-6407
Country: USA


Extended Metadata Properties
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Creation and Review Dates
SERF Creation Date: 2012-10-22
SERF Last Revision Date: 2018-05-31



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