558 THE FORSTER TERN. 



of hind head and nape; tail shorter and not so deeply forked, the outer feathers 

 broader and less tapering ; bill iduUer, the dusky tip scarcely contrasting ; feet dull 

 reddish, young: Like adult in winter, but upper parts varied by, or overlaid 

 with, light brownish ; sides of head more or less tinged with the same shade ; tail 

 shorter, its- feathers becoming dusky terminally. Length 14.00^15. oo (355-6-381.) ; 

 wing 10.00 (254.) ; tail, the central feathers, 2.80 (71. i) ; the lateral pair 6.75-7.00 

 (171. 5-179. i) ; 1)111 1.57 (39.9) ; depth at base .46 (10.2) ; tarsus .98 (24.9). 



Recognition Marks. — Size of Common Tern ; distinguishable from it by 

 subtle but sure marks; the bill is stouter and more extensively black on terminal 

 portion ; the upper tail-coverts are grayer ; the tail more deeply forked, and the 

 outer pair of feathers dark on inner webs. 



Nesting. — Not known to breed in Ohio. Ncstj in colonies, on the ground 

 of low islands, in grass, etc., lined with grasses, flags, and the like. Hggs, 2 or 3, 

 rarely 4, dull white, greenish white, olive-gray, ashy-brown, etc., spotted and 

 blotched with blackish brown or umber, and with shell-marks of stone gray and 

 lavender. Av. size, 1.80 x 1.25 (45.7 x 31.8). 



General Range. — North America generally, breeding from Manitoba south- 

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



Range in Ohio. — Apparently a rare migrant; not yet recorded from Lake 

 Erie. Probably more frequent than records would show, but often passing for 

 succeeding species. 



COMPARATIVELY little is known of this Tern as an Ohio> bird, its 

 great similarity to the next species serving to shield it from the gaze of any 

 but the initiated. Dr. Wheaton's acquaintance with it was limited to a single 

 specimen taken near Columbus in the fall of 1861 or 1862. Six specimens 

 were taken by Messrs. Dury and Freeman near Cincinnati, May 4th, 1879. 

 Examples are more numerous from Indiana, but no breeding records are 

 reported by Professor Butler. Several observers, however, report it as breed- 

 ing on the St. Clair Flats, in Michigan, and Mr. E. W. Nelson gives a full 

 account of its nesting about the shallow lakes of northeastern Illinois. It 

 would seem, therefore, that the species must regularly cross our state, even 

 tho its principal ranges lie further to the east and west. 



According to Mr. Ridgway, who found the species abundant at Cobb's 

 Island, Virginia, the Forster Tern is preeminently a marsh tern. Its nests 

 are usually placed on masses of floating vegetation or broken-down reeds. 

 At Cobb's Island they were found in close proximity to those of the Black- 

 headed Gull (Larus atricilla) while in Illinois the chosen nesting site brings 

 the bird into frequent comparison with the Black Tern. 



This species can be readily distinguished from the Common Tern, which 

 it closely resembles when on the wing, by its grating monotonous nste, which 

 recalls one frequently uttered by the Loggerhead Shrike. 



