The Black Tern 



No. 290 



Black Tern 



A. O. U. No. 77. Chlidonias nigra surinamensis (Gmelin). 



Description. — Adult in summer: Head and neck all around, glossy black, 

 shading into sooty black of underparts; the crissum white and the edges and lining of 

 wings white or pale pearl-gray; upperparts plumbeous, darker on upper back, where 

 it blends through slate with black cervix; bend of wing white; primaries inclined to 

 silvery on exposed webs after the first, the inner webs, however, dusky, lightening on 

 the inner half, and the shafts white; tail slightly forked. Bill and feet black. Adult 

 in winter: Lighter, the black replaced by white, save on back of head, orbits, and 

 auriculars, where obscurely persistent; upperparts deep pearl-gray. Immature: Like 

 adult in winter, but upperparts more or less tinged and tipped with brownish, and sides 

 washed with grayish. Length 228.6-260.4 (9.00-10.25); wing 203.2-215.9 (8.00-8.50); 

 tail 76.2 (3.00); bill 26.4 (1.04); tarsus 17 (.67). 



Recognition Marks. — Towhee to Robin size, but appearing about Killdeer 

 size; sooty black and plumbeous coloration distinctive in breeding plumage; dark 

 pearl-gray of upperparts with black bill (and feet), with small size sufficiently distinctive 

 at other seasons. 



Nesting. — Nests in loose colony fashion, each a truncated cone of twisted 

 grasses or bent sedged, placed on ground in marshes or on drifting reeds, old grebe 

 nests, or anything which offers support on the surface of the water. Eggs: 3 (4 of 

 record) ; olive-buff to dark olive-buff, or cinnamon-buff to clay-color and tawny olive, 

 heavily spotted and wreathed, or strikingly blotched, or even rough-banded, with 

 black or reddish black (dark bister to dark vandyke brown). Av. of 15 sets in M. C. 

 O. coll.: 33.5 x 23.9 (1.32 x .94); index 71. Season: c. June 1st; one brood. 



Range of Chlidonias nigra. — Europe and temperate North America, south in 

 winter to Africa (both coasts) and South America. 



Range of C. n. surinamensis. — Breeds in interior North America from south- 

 western British Columbia, Mackenzie (Great Slave Lake), and southern Keewatin, 

 southeastward to eastern end of Lake Ontario, thence southwestward through northern 

 Ohio, Kansas, etc., to southern California. Of general occurrence near water during 

 migrations, but especially coastwise, south through Mexico and Central America to 

 the Guianas, Peru and Chile. 



Distribution in California. — Breeds commonly at suitable places in the 

 interior, both east and west of the Sierras, and as far south as Buena Vista Lake (Lin- 

 ton) and possibly Lake Elsinore (Heller). Of rare occurrence coastwise above Point 

 Conception, but abundant during migrations in the Santa Barbara sector. 



Authorities. — Cooper (Hydrochelida plumbea), Proc. Calif. Acad. Sci., vol. ii., 

 1861, p. 122 (headwaters of Mojave River); McAtee, U. S. Dept. Agric, Farmers' 

 Bull. 497, 1912, p. 24 (food) ; Tyler, Pac. Coast Avifauna, no. 9, 1913, p. 14 (San Joaquin 

 Valley; breeding habits). 



IRRIGATION has caused the desert of the West to blossom as the 

 rose. If that were all, we could be thankful for roses — and such, roses! 

 California roses, of course! But when to roses are added such practical 



14.60 



