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 the interactive mapping tool named North American BBA Viewer.

BBA Viewer (North American BBA Viewer) is a mapping tool designed to display data from state and provincial Breeding Bird Atlases, with results and descriptive information available in a single format. Data can be mapped at the block or quad level for both current and published BBA projects. See the Features Gallery for more information on what you can do with this mapping tool and what end products you can create.

BBA Manager is an 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 BBA Manager page to learn more about it and see the current atlas projects!

Add your BBA results to BBA Explorer, all we require is an electronic copy of the 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 contact Mark Wimer for more information, or click here to learn more about adding your atlas.

View premade maps in the Features 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!

Download data from the Get Data page and create your own maps in GIS software or Google Earth.

Starting an atlas in your state or province? See Adding Your Atlas.

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