What is a Breeding Bird Atlas? A Breeding Bird Atlas (BBA) is a population survey project designed to cover large geographic areas using a grid based system and is generally organized at the state or provincial level. Each participant in the project, referred to as an observer or 'atlaser', is assigned one or more blocks (grid cells) in which to conduct extensive area searches. They record any breeding evidence observed for each bird species; this evidence is categorized as “confirmed”, “probable” or “possible”. The results can be mapped and will then provide comprehensive information about the distribution of breeding birds in the region covered. For more information on BBAs see the North American Ornithological Atlas Committee (NORAC) website.

BBA Explorer (this website) offers data from published BBAs and interim data from ongoing BBAs in North America in a uniform system. It allows users to learn about the methods used in each atlas project, to get species and block information for each project, and to view the results by species, block, or region in a table or map format. Most descriptive information and tabular results are available through each Atlas Home page and maps are available through our BBA Species Map tool.

Starting an atlas in your state or province? BBA Manager is our online data management system for atlases in progress and maintains interim data. These data are displayed in BBA Explorer with regular updates and allow observers for each atlas project to enter their data directly into the database. Check out the About BBA Manager page to learn more about it and see the current atlas projects! If you are planning an atlas, please see our guidelines in Information Management for Breeding Bird Atlas presented at the 2004 NORAC meeting for help in planning a BBA project. You should also sign up for the NORAC discussion list mentioned on the NORAC site.

Add your BBA results to BBA Explorer. To include results from your state, province, or other published atlas, we will need an electronic copy of your atlas dataset. Or if you are conducting an atlas now and would like to have up-to-date results displayed through BBA Explorer, consider using BBA Manager. Please use the contact form to request more information.

Make your own maps using our BBA Species Map tool, or download data from the Get Data page and create your own maps in GIS software or Google Earth.

View premade maps in the Map Gallery. There are several different file types so you can view or save the maps on your computer. If you like the maps we've created for you, try making your own with data from the Get Data page or with BBA Viewer!

Still have questions or comments? Is there something we could explain better or should include here? Just fill out this brief form to let us know!