Abstract

Abstract We used a three-year point-count data set from Hoosier National Forest, Indiana, to evaluate alternative point-count sampling strategies for detecting songbird declines. Repeated-measures ANOVA indicated that mean abundance estimates increased with increasing count radius (P < 0.0001, each species), and coefficients of variation (CVs) decreased. Mean abundance estimates increased with longer count duration (6-, 8-, and 10-min) for only two of 13 species, and CVs did not necessarily decrease. The power to detect a 5% annual population trend increased with more survey points, more visits per point, and more years of surveys. Managers can use observer time most efficiently by employing counts of short duration. Counts using a larger radius will reduce CVs and therefore provide potentially better annual estimates of abundance and power to detect changes over a period of years. The design of the study and nature of the variability in bird abundance will determine whether increasing the number of point...

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.