Skip to page content
USDA Forest Service

Research & Development Treesearch

Treesearch Home
About Treesearch
Contact Us
Research & Development
Forest Products Lab
International Institute of Tropical Forestry
Pacific Northwest
Pacific Southwest
Rocky Mountain
Southern Research Station
Help - We Participate  Government Made Easy

Global Forest Information Service

US Forest Service
P.O. Box 96090
Washington, D.C.

(202) 205-8333

You are here: Home / Search / Publication Information
Bookmark and Share

Publication Information

View PDF (331 KB bytes)

Title: An investigation of the effect of seasonal activity levels on avian censusing

Author: Ralph, C. John;

Date: 1981

Source: Studies in Avian Biology 6:265-270

Publication Series: Miscellaneous Publication

Description: Intensive variable distance circular-plot censuses and timed activity budget data were used to compare the effects of conspicuousness upon census results. In six of ten species no correlation was found, suggesting that all birds within the "Effective Detection Distance" (EDD) were seen. In four species there were significant correlations. Multiple regression analyses confirmed these results. Generally larger correlations were found with the number of birds per station than with density per ha; the latter is presumed to correct for changes in conspicuousness, possibly through changes in the EDD. However, a completely unexpected result showed that the EDDs themselves, while showing cycles, did not correlate with the activity variables. This indicates that, although they probably have biological meaning and are relevant to censusing, EDDs are not simply related to obvious changes in conspicuousness as measured by activity patterns.

Publication Notes:

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.



Ralph, C. John 1981. An investigation of the effect of seasonal activity levels on avian censusing. Studies in Avian Biology 6:265-270


 [ Get Acrobat ]  Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.