Dedicated to Chandler S. Robbins, originator of the survey, to honor his 50 years of government service |
Most Recent Update: 24 June 2001.
(1) This is the first release of the 1966 - 2000 analysis.
(2) The BBS database has undergone extensive revisions
in 1998-2000, and many of the changes will be reflected in the results.
Please let us know about any problems you encounter!
(3) Some 1966 - 1996 analyses (e.g., distribution maps) have been retained here, but most of the
trend results from earlier analyses have been moved to archives.
(4) Some species are grouped for analysis. These are indicated on the selection lists.
(5) Earlier versions of the web site have been archived, and are accessible via links.
(6) A credibility index has been added to trend results. This symbol flags imprecise, small sample size,
or otherwise questionable results.
(7) Most recent update: 24 June 2001. Analysis was rerun is reponse to referee questions and comments. Sample sizes
were slightly reduced, as nonrandom routes were eliminated in the final analysis.