18 BIRDS OF PENNSYLVANIA, 



often hover over the water, when feeding, in the same manner as the Sparrow Hawk 

 does when hunting in a grass-field, and dart head foremost into it, oftentimes with 

 such force as to submerge the whole body ; unlike the hawk, however, which 

 seizes his prey in his talons, the Tern captures its prey in its bill. Their notes are 

 sharp, shrill and often repeated ; they are particularly noisy when wounded or if their 

 breeding-places are approached. The eggs, two or three in number, are generally 

 deposited in a slight depression in the sand or shingle along the sea-beach ; some 

 few nest on drift-stuff, sea-weeds, grasses, etc., in marshes, and others, it is stated, 

 construct rude and rather bulky nests of sticks on trees or in low, thick bushes. 

 Terns are of a gregarious nature ; they frequently nest in great numbers in suitable 

 localities, and when migrating they often assemble in large flocks. Great numbers 

 of these birds, and many of the smaller kinds of Gulls, are annually slaughtered 

 along the Atlantic coast by heartless and greedy "feather hunters" to supply the 

 millinery establishments of our large cities. 



GENUS GELOCHELIDON BREHM. 

 Gelochelidon nilotica (HASSELQ.). 



Gull-billed Tern ; Marsh Tern. 



DESCRIPTION. 



Adult. Bill short, stout and resembles somewhat that ot a gull ; top of head 

 black, which runs downward on sides to lower eyelid ; a very narrow line of white 

 at base of upper mandible ; back and wings pearly bluish-gray ; tail feathers very 

 similar to back, but lighter ; lower part of back of neck and entire under plumage 

 pure white ; bill and tarsi black ; iris dark brown. Length about 14 inches ; extent 

 about 3* inches. 



The young have brownish-colored bills and legs, top of head largely white ; upper 

 parts more or less spotted with brown. 



H'lbita . Nearly cosmopolitan ; in North America cbiefly along the Atlantic and 

 Gulf coasts of the United States. 



This species is a very rare and irregular visitor in eastern Pennsyl- 

 vania, and in the central and western portions of the state I find no one 

 has noted its occurrence. Mr. H. B. Graves records the capture of one 

 "in Chester county in autumn." Mr. C. D. Wood informed me he ob- 

 tained two specimens, which were shot near Philadelphia about five 

 years a^o. I have never seen this bird in Pennsylvania. 



GENUS STERNA LINNAEUS. 

 Sterna tschegrava LEPECH. 



Caspian Tern. 



DESCRIPTION. 



Largest of all the Terns ; bill large and stout, measuring about three inches ; tail 

 very slightly forked. 



" Adult. Forehead, crown, sides of the head and occiput black, glossed with 

 green ; this color extends below the eye, under which is a narrow white line ; back 

 and wings light bluish-ash ; outer six primaries dark slate-gray on their inner webs ; 

 quill shafts strong and white ; tail and its upper coverts grayish-white ; neck and 

 entire under plumage pure white ; bill and inside of mouth bright vermillion legs 



