Koenig and his co-author, Andrew Liebhold, an ecologist at the U.S. Department of Agriculture Forest Service in Morgantown, West Virginia, analyzed avian population data from the North American Breeding Bird Survey from 1966 to 2010. (sciencemag.org)
«In many places the numbers are so low that the established general breeding bird surveys do not encounter them enough to give us reliable information. (politics.co.uk)
Populations and Ecological Traps In addition, Marra's suggestion that «these suburban areas [are] ecological traps for nesting birds» is contradicted by the results of bird surveys in Maryland. (voxfelina.com)