298 Field Museum of Natural History — Zoology, Vol. IX. 



Genus GELOCHELIDON Brehm. 



22. Gelochelidon nilotica (Hasselq.). 

 Gull-billed Tern. 



Distr. : Nearly cosmopolitan ; occurs in North America chiefly along 

 Gulf of Mexico and Atlantic coast as far north as New Jersey (ac- 

 cidental in Massachusetts) ; winters from the West Indies and Mexico 

 south to Brazil. 



Adult in summer: Top of head and nape, black; upper part, includ- 

 ing rump and tail, pearl gray; under parts, white; bill and feet, black, 



the former comparatively short 

 and stout. 



Adult in winter : Similar, but 

 having the head and neck white, 

 the nape, ashy, and a dusky 

 patch in front of the eye. 



Length, 14; wing, 12; tail, 

 5.50; bill, 1.40; tarsus, 1.30. 



It is far easier to establish a 

 record than it is to reject one, 

 because we must assume that an 

 author who makes the statement that a bird occurs in a certain 

 locality must have a satisfactory reason for so doing. It is not 

 given on hearsay evidence, but is a plain statement of fact, or must 

 be accepted as such until we have good reason to doubt it. There- 

 fore, although I have never seen a specimen of this Tern taken 

 either in Illinois or Wisconsin, and can find no record of its actual 

 capture in either state, I include it upon the authority of the 

 following published statements. 



"An exceedingly rare visitant during summer." (Nelson, Birds 

 N. E. 111. ,,1876, p. 147.) "Rare summer visitor." (Ridgway, Cat. 

 Birds Illinois, 1881, p. 202.) " Rather common." (A. J. Cook, Birds 

 Michigan, 1893, p. 34.) Also included in Prof. Ridgway's Ornithology 

 of Illinois, probably on some other authority, as he makes no remarks 

 whatever concerning it. It was included by Dr. Hoy in his list of 

 Wisconsin Birds of 1852. Kumlien and Hollister say: "We know 

 of no actual record for Wisconsin and have never seen the bird in 

 the north." (Birds of Wisconsin, 1903, p. 130.) 



