Determining population size of territorial red-winged blackbirds

Journal of Wildlife Management



Population sizes of territorial male red-winged blackbirds (Agelaius phoeniceus) were determined with counts of territorial males (area count) and a Petersen-Lincoln Index method for roadsides (roadside estimate). Weather conditions and time of day did not influence either method. Combined roadside estimates had smaller error bounds than the individual transect estimates and were not hindered by the problem of zero recaptures. Roadside estimates were usually one-half as large as the area counts, presumably due to an observer bias for marked birds. The roadside estimate provides only an index of major changes in populations of territorial male redwings. When the roadside estimate is employed, the area count should be used to determine the amount and nature of observer bias. For small population surveys, the area count is probably more reliable and accurate than the roadside estimate.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Determining population size of territorial red-winged blackbirds
Series title Journal of Wildlife Management
Volume 40
Issue 4
Year Published 1976
Language English
Contributing office(s) Patuxent Wildlife Research Center
Description 761-768
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Journal of Wildlife Management
First page 761
Last page 768