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The North American Breeding Bird Survey-BBS

Version 6-17-2016

What is the Home Page?

The BBS Summary and Analysis Website is a source of information about population change and distribution of many North American bird species. It is also a tool for learning about birds, with connections to our websites containing ID tips with pictures of common North American birds and quizzes on bird distribution and identification.

This website is a supplement to the BBS Operations Website. The BBS Operations Website is the appropriate source for "raw" (unsummarized) BBS data, for additional information on the details of running and maintaining the survey, and for links to additional BBS resources.

What is the BBS?

The BBS is a large-scale survey of North American birds. It is a roadside survey, primarily covering the continental United States and southern Canada, although survey routes have recently been initiated in Alaska and northern Mexico. The BBS was started in 1966 and now contains over 5,000 survey routes which are surveyed in June by experienced birders.

The primary objective of the BBS has been the estimation of population change for bird encountered along roadsides. However, the data have many potential uses, and investigators have used the data to address a variety of research and management objectives.

How does the Results and Analysis Home Page work?

The website provides information on (1) population change estimates of bird species at several geographic scales; (2) population change estimates for species groups; and (3) maps of bird species distributions and population change. The Results and Analysis home page provides links to detailed information on these categories.

Results are generally presented as clickable lists, where regions or species are selected and the website provides summry results from underlying results of analyses with were previously conducted. This way, we provide results that have been reviewed, as consistent with USGS regulations regarding release of information. On-the-fly interactive programs permit additional analyses that are based upon the same underlying analyeses but permit more flexibility in regions and time periods of summary.

Some users will find the clickable list structure of the Summary and Analysis Website to be "old fashioned." We have retained this overall structure to meet the needs of many users of the data, who often harvest results from these lists and thus appreciate consistency in presentation from year to year.

Supplemental Information

Analysis and interpretation of BBS data is tricky, because the survey incorporates information from a huge geographic area and the survey varies greatly in quality of information over the area. To document some of the problems with the analyses of BBS data, and help you interpret the results presented on the Home Page, we provide a series of help files that provide information on the survey, discuss problems with its analysis, and tell you how the presented information should be interpreted. We suggest you read the help files for each category of information before looking at the results.

Help files and metadata are presented with summary data, and are also available in the References and Additional Information link on the web site.

Learning about birds with the Home Page

The BBS is an important source of information on where birds occur during June in North America. The maps of abundance provided here allow you to test your knowledge of breeding bird distributions. To help with the test, we provide a quiz of bird distributions in which you guess the species for a randomly- selected abundance map.

We also provide pictures of some of the bird species covered by the BBS. In this version of the Home Page, we provide more pictures of birds, and we provide songs of common birds.

Comments and Disclaimers

We welcome comments on the home page. We intend to improve it as new methods for summary of survey data are developed, and in response to user feedback. We caution that, as always in data analyses, the possibility exists for errors in the analyses and summaries.


Any analysis of BBS data must first acknowledge the large number of observers who conduct the counts. These counts are a lot of effort, and require a great deal of skill. We greatly appreciate their efforts. Of course, Chan Robbins, the originator of the survey, is still the primary source of energy and inspiration for analyses and interpretation of this challenging data set. A variety of data managers and coordinators, including Chan Robbins, Ted Van Velzen, Danny Bystrak, Sam Droege, Bruce Peterjohn, Keith Pardieck, and David Ziolkowski (on the US side), and Tony Erskine, Marie-Anne Hudson, Connie Downes, and Bev McBride (on the Canadian side) have contributed to the program. We especially thank the many editors and data managers and other BBS staff who have contributed to the analysis for making the data and their expertise available to us. Daniel Niven reviewed the website.

BRD Data Liability Disclaimer

Although these data have been processed successfully on a computer system at the United States Geological Survey (USGS), 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 USGS source, 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 USGS 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.