"eaglblit.gif" text="#000000" link="#800000" vlink="#888888"
North American Breeding Bird Survey
Species Group Summaries
Select a time period, region, and species group, and this program will produce a summary of trends. The summary includes:
- Number of species,
- Proportion of species with positive trend estimates,
- Proportion of species with significant (+ and -) trend estimates, and
- List of species and their trend estimates.
1966 - 2003 Analysis
See the BBS Summary and Analysis Website for citation, version number, and cautions regarding use.
We also provide some estimates of mean trend and a ranking of species from most extreme decline to most extreme increase, using the procedures given in Link and Sauer 1996. These results adjust estimates for relative precision, and you can estimate:
- Precision weighted mean trend (called a prior mean),
- 95% Confidence interval on the prior mean, and
- Rankings of species based on an precision-weighted reordering of the estimates.
These results are based on the Route-regression, estimating equations method.
Return to Home Page
ver 2003.1, 5 January 2003, Authors: J. R. Sauer and J. E. Hines.
BRD Data Liability Disclaimer
Although these data have been processed successfully on a computer system at the USGS Biological Resource Division, no warranty expressed or implied is made regarding the accuracy or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data. It is strongly recommended that these data are directly acquired from a Biological Resource Division server, and not indirectly through other sources which may have changed the data in some way. It is also strongly recommended that careful attention be paid to the contents of the metadata file associated with these data. The Biological Resource Division shall not be held liable for improper or incorrect use of the data described and/or contained herein.
So, these data are provided "as is" and without any express or implied warranties, including, without limitation, the implied warranties of merchantability and fitness for a particular purpose. Also, use of trade names or commercial products in this home page is solely for the purpose of providing specific information, and does not imply recommendation or endorsement by the U.S. Government.