20 BIRDS OF PENNSYLVANIA. 



Habitat. North America generally, breeding from Manitoba southward to Vir- 

 ginia, Illinois, Texas and California ; in winter southward to Brazil. 



This species is found in Pennsylvania as quite a rare and irregular 

 visitor during the spring and fall migrations. In the summer of 1879 

 I visited Cobb's Island, Virginia, where this Tern was breeding quite 

 plentifully in the marshes. Forster's Tern feeds principally on little 

 -fish. 



Sterna hirundo LINN. 



Common Tern ; Wilson's Tern ; Sea Swallow 



DESCRIPTION. 



Adult. Bill (dried skin) red from base to about half its length, then black, with 

 pale-yellowish point ; iris brown ; legs reddish-yellow ; upper part of head and 

 hind neck black ; back and wings light bluish-gray ; sides of neck and head, line 

 along base of upper mandible, chin, throat, upper and lower tail coverts and most 

 of tail, also lining of wings, white ; the outside tail feather has black outer web ; 

 sides of breast and of lower part of neck and rest of lower parts grayish-white. In 

 the young the bill is blackish and yellow, the latter color especially on lower mandi- 

 ble ; tarsi yellowish ; front of head and entire under plumage white ; crown gray- 

 ish-white and black plumage about eyes, back of head and upper part of hind neck 

 dull black ; back and wings indistinct bluish-gray with patches of light-brown ; 

 most of feathers on back edged with white. Length about 14| inches : extent about 

 31 inches. 



Habitat. Greater part of the Northern Hemisphere and Africa. In North 

 America chiefly confined to the Eastern Province, breeding from the Arctic coast, 

 somewhat irregularly, to Florida and Texas, and wintering northward to Virginia. 



The Common Tern or " Sea-Swallow," as this bird is commonly called 

 by fishermen on the coast of New Jersey, is one of few species of this 

 group, which has been frequently found in different sections of our 

 state during migrations. Mr. George B. Sennett has observed it as an 

 irregular migrant in the spring and fall in the vicinity of Erie city, 

 where, I have no doubt, it is oftener met with than in any other section 

 of Pennsylvania. Dr. John W. Detwiller, of Bethlehem, in a letter ad- 

 dressed to me, says : I have shot the Common, Arctic and Least Terns 

 on the Lehigh river in the fall, and he further adds they were " prob- 

 ably driven inland by severe storms." Mr. August Koch, notes the 

 species as an irregular migrant spring and fall in Lycoming county, 

 and Dr. Walter Van Fleet, of Renovo, has found it in Clinton county as 

 a straggler. InBerks county Mr. D. Frank Keller, of Reading, reports 

 that he has observed it as an accidental visitor ; according to Dr. A. C. 

 Treichler, of Elizabethtown, this bird is a straggler of rare occurrence in 

 Lancaster county. Prof. J. R. Robertson, of Franklin, Venango county, 

 mentions the Common Tern as a very rare and uncertain visitor in that 

 locality. Several specimens of this species have been captured when 

 migrating, particularly in the autumn, in the counties of Chester, Dela- 

 ware and Philadelphia. The Common Tern breeds in New Jersey and 

 elsewhere along the Atlantic, and also about many of the large inland 

 lakes and ponds. 



