About the Atlas

The Maryland/DC Breeding Bird Atlas is a project which aims to map the distribution of all breeding bird species in the state. The atlasing effort will extend over 5 years starting in Jan 2002. This current atlas will up-date an earlier atlas completed in 1983 and reveal changes in distribution since then. Future versions will no doubt be compiled in the decades and indeed centuries to come.

The atlasing grid consists of "blocks" formed by the standard USGS 1:24000 topo maps as divided into sixths: NW,NE, C("central")W,CE,SW,and SE. This makes about 1300 blocks in all, each about 3 miles on a side. The presence of a single breeding pair within an Atlas block constitutes a data point in the breeding distribution of that species. For higher resoltion, the Blocks in central MD plus Garrett and Dorchester Counties are further divided into quarter-blocks. The resolution in time is the entire 5 years of data collection - the appearance of a bird in a block for any year of the 5 year period will count as a data point even if it subsequently disappears from the block before the count period is over.

Each Atlas block is assigned a "captain", who takes on the responsibility for finding the breeding birds in that block. All birders are invited to report any breeding evidence they come across anywhere in the state, whether or not in a block assigned to them.

For more information see The Maryland Ornithological Society's Atlas Page

Sign up for an Atlas block

To select a block within PG County

Refer to PG Co map and click on desired grid square, then return via "select this block"

To proceed directly to data entry

Connect to data entry website http://www.mp2-pwrc.usgs.gov/bba/MDDC2002_index.cfm

Return to Home page