418 NATUKAL HISTORY. 



201. Bucephala albeola, (Linn.,)Baird. — Buflfel-heacled duck; "But- 

 ter-ball." Winter resident. More common than preceding. Ar- 

 rive in fall, about the middle of September; leave in spring, the 

 second week in April. 



202. Harelda glacialis, (Linn.,) Leach. — Long-tailed duck. 



203. Ilelanetta velvetina, (Cass.,) Baird. — Velvet duck. 



204. Pelionetta 2^erspiciUata, (Linn.,) Kaup. — Surf duck. 



205. Oidemia americaoia, Swainson.^ — Scoter duck. 



(The four preceding birds do not properly belong to the fauna of 

 the District, being strictly marine birds. They are found at the 

 mouth of the Potomac, and ascend it as far as the salt water reaches. 

 Their appearance in this immediate locality must, however, be con- 

 sidered accidental. They are all to be seen in the market during the 

 winter.) 



206. Erismatura riibida^ (Wils.,) Bon. — Ruddy duck. Winter res- 

 ident. Abundant. Frequently exposed for sale in the market, but 

 not esteemed for food. 



207. Mergus americanus, Cassin. — Goosander. "Fishing duck." 

 Winter resident. Not common. More frequently seen on creeks and 

 millponds than on the rivers. 



208. Mergus serrator^ Linn. — Red-breasted merganser. "Fishing 

 duck." Winter resident. Rather more common than the preceding. 

 Found in much the same situations. 



209. Lopliodytes cucullatus, (Linn.,) Reich. — Hooded merganser. 

 Winter resident. Rather rare. 



210. Thcdassidroma leachii, Bon. — Leach's Petrel. Accidental 

 visitor. (Numbers were seen during a storm some years ago.) 



211. Pufflnus, ? A shearwater, probably P. ohscurus, has 



been detected in the District. 



212. Larus smithsonianus,^ Coues. — Herring gull. "Sea gull." 

 Seen over the river through the winter. Not numerous. Exceed- 

 ingly shy and wary. 



213. Larus delaivarensis, Ord. — Ring-billed gull. Seen about the 

 river during the winter months. More numerous than the preceding. 



214. Ghroicocephalus atricilla, (Linn.,) Lawr. — Laughing gull. Oc- 

 casionally seen during the late summer and early autumn months. 



215. Chroicoceplialuspj]iiladel}jMa, (Ord. , )Lawr. — Bonaparte' s hooded 

 gull. More abundant than the preceding, being quite common. Re- 

 mains here through the winter. (?) 



216. Sterna aranea, Wils. — Marsh Tern. Rare; only occasionally 

 seen during the late summer and early fall months, over the marshes 

 bordering the river. 



217. Sterna wilsonii, Bon. — Wilson's Tern. An occasional visitor 

 during the late summer and early fall months. [Sterna forsteri is 

 undoubtedly to be found in the District.] 



218. Sterna frenata, Gambel. — Least Tern. Not uncommon. Fre- 

 quently seen over the marshes bordering the Potomac and Eastern 

 Branch in August and September, and more rarely in spring. 



219. Hydrochdidon plumbea, Wils. — Short-tailed Tern. "Little 



«See Proc Acad. Nat. Sci., Philadelphia, June, 1862, p. 296. 



