Program and Agenda

Abstract

DIFFERENT FOREST BIRD POPULATION TRENDS FROM BBS AND FOREST INTERIOR MONITORING SITES

Numerous studies have shown that bird habitat sampled by the North American Breeding Bird Survey (BBS) is approximately representative of available habitat at the regional scale. Other studies have shown that the relative abundance of many species varies between the near-road areas sampled by the BBS and areas further from the road. But few studies have demonstrated differences in population trends between BBS and off-road sites in the same region. The Ontario Forest Bird Monitoring Program is a volunteer-based monitoring program that was initiated in 1987, in part, to evaluate temporal trends in abundance for birds with strong affinities for forest habitat. Using essentially identical Bayesian hierarchical models, we estimated population trends for forest birds in Ontario, doing so separately for the BBS data and the FBMP data. We compared the trends from the two programs using an additional hierarchical Bayesian model that accounted for the uncertainties associated with trend estimates. Overall, population trends from the FBMP data were more negative, indicating that for a given species, populations monitored in forest interiors (FBMP) were more likely to be in decline and/or more steeply declining than populations monitored on roadsides (BBS). That trends are different between populations monitored by the two programs may have important implications for both programs and for conclusions related to population status and trend assessment. Understanding those implications will be part of ongoing work to clarify possible mechanisms behind the differences and to evaluate the proportion of the regional bird populations represented by each program.

Authors

Miller, D. A., Pennsylvania State University, USA, dxm84@psu.edu

Smith, A. C., Environment Canada, Canada, adam.smith@ec.gc.ca

Cadman, M., Environment Canada, Canada, mike.cadman@ec.gc.ca

Russell, R., Environment Canada, Canada, rich.russell@ec.gc.ca

Weeber, R. C., Environment Canada, Canada, russ.weeber@ec.gc.ca

Details

Oral presentation

Session #:S13
Date: 9/26/2014
Time: 17:00
Location: Emerald Mountain - Bible Point

Presentation is given by student: No