176 MIGRANTS AND WINTER RESIDENTS 



waters within the District, but it is no uncommon 

 sii^ht to see files of geese flying over, and they are 

 found in the markets and restaurants all through the 

 winter." (Avifauna Columbiana.) 



American Herring Gull; Sea Gull: Larns ari^ciifafiis 



smithsoniaiius. 



Back and wings pearl-gray, the wings with black mark- 

 ings: rest of plumage white. Length 2 feet. October to 

 March. Common, especially in spring. Flocks of this and 

 the following species may often be seen at low tide on the 

 mud flats along the Eastern Branch. 



Ring-billed Gull: Lants dclaivarcnsis. 



Back and wings pearl-gray; wings marked with black and 

 white; rest of plumage white; bill greenish-yellow, encircled 

 near the end with a broad black band. Length 20 inches. 

 February to April S; October to November. Very common. 



Bonaparte's Gull: Lanis philadcll^Jiia. 



Much smaller than the preceding. Li summer, head and 

 upper neck dark slate color; back and wings pearl-gray; 

 rest of plumage white. Immature birds and adults in fall 

 without black head. Length 14 inches. April to May 5; 

 October to November. Common. 



Black Tern: Hydrochdidon nigra surinamensis. 



In summer, head, neck and under parts black; back, wings 

 and tail slate color; bill and feet black. In winter, forehead 

 and under parts white. Length 10 inches. Sometimes com- 

 mon in Augus't and September. 



Loon: Gai'ia iinbcr. 



Head and neck dark bluish-green, patches of mottled 

 white on throat and sides of neck; upper parts and sides 

 glossy black, conspicuously spotted with white; under parts- 

 white. Length 2^ feet. September to April 25. Common. 



