A pilot Breeding Bird Atlas was initiated during 1971 in Montgomery County. A second atlas was begun during 1973 in Howard County. The Montgomery project was completed in 1973 and the Howard project in 1975......A total of 138 species were recorded for the two counties (129 confirmed, 7 probable, 2 possible). Montgomery County had 135 species recorded (122 confirmed, 9 probable, 4 possible) and Howard County had 127 species (110 confirmed, 7 probable,10 possible)......Thirty-two species were found in all 5-km blocks and eight were found in all 5-krn and 21/2-km blocks. Two species were confirmed in all blocks.......There were 11 new Montgomery County breeding records and eight new Howard County records. Nine species were found only in Montgomery County and two only in Howard County. Twelve species were confrmed in Montgomery County but not in Howard; five were confirmed in Howard County but not in Montgomery. Ninety-eight species were confirmed on active nests in Montgomery County and 85 in Howard County.