BIRDS OF PENNSYLVANIA. 23 



Habitat. Tropical and subtropical coasts of the globe. In America from Chili to 

 western Mexico and the Carolinas, and casually to New England. 



The Sooty Tern is a rather rare and irregular visitor in Pennsylvania 

 during- the spring and fall migrations. About five years ago two of 

 these Terns were taken in Delaware county, and I have two specimens 

 in my collection that were killed in Chester county. Dr. John W. Det- 

 willer, of Bethlehem, has observed it in his locality. Dr. A. 0. Treich- 

 ler mentions this bird as a straggler in the neighborhood of Elizabeth- 

 town, Lancaster county. Specimens captured in Ly coming county, in 

 the spring and fall, are in the valuable collection of my esteemed friend, 

 Mr. August Koch, of Williamsport. Prof. J. E. Eobertson writes me 

 that the Sooty Tern is an accidental visitor in Yenango county. 



GENUS HYDROCHBLIDON BOIE. 

 Hydrochelidon nigra surinamensis (GMEL.J. 



Black Tern ; Short -tailed Tern. 



DESCRIPTION. 



Adult, in spring and breeding plumage. Head, neck and under parts black, 

 darker on head and neck than on abdomen, where the color is sooty-black ; edge of 

 wing and under tail coverts white ; back, wings, rump, and tail, lead color ; under 

 surface of wings somewhat lighter than the upper parts ; bill (dried skin) black; 

 tarsi brownish-yellow ; iris brown. Length about 9 inches ; extent about 24 inches. 

 Adults in winter, and young in the fall have head, neck and under parts mostly 

 white. 



Habitat. Temperate and tropical America. From Alaska and the fur countries 

 to Chili, breeding from the middle United States northward. 



The Black or Short-tailed Tern is a rather irregular, though not an 

 uncommon visitor during- the spring and fall in different sections of 

 Pennsylvania. In North America this species has quite an extended 

 distribution, being found both along the sea-coasts and about marshes, 

 lakes and reedy ponds in the interior. According to various writers it 

 breeds more or less abundantly about marshes in Wisconsin, Minnesota, 

 Michigan, Dakota, Oregon, etc. Dr. John W. Detwiller, an ornitholo- 

 gist of over twenty-five years' experience, residing at Bethleham, North- 

 ampton county, Pa., writes me, that, some years ago he "procured eggs 

 of the Black Tern upon drift-wood on Lake Erie, near Erie city." I 

 have never had an opportunity of observing these birds when breeding, 

 and I am not aware that they are now known to breed anywhere in the 

 neighborhood of Erie county or elsewhere in our state. The following 

 remarks relative to this species in the breeding season are taken from 

 Mr. F. W. Langton's " Summer Birds of a Northern Ohio Marsh :" 

 " A very common summer resident in the marsh, nesting, or rather lay- 

 ing its eggs on the islands of decaying vegetation and mud formed by 

 sunken muskrat houses. Three eggs constitute a full set, and they are 

 apparently rolled about in the mud purposely, until well-coated, so as 



