THE COIMMON TERX. 751 



• No. 301. 



COMMON TERN. 



A. C). U. Xo. 70. Sterna hirundo Linn. 



Synonyms. — Wilson's Terx. Sea Swallow. "Bass-gl'll." 



Description. — Adult in summer: Top of head and nape uniform deep black; 

 back and wings pearl-gray ; wing-quills dusky, more or less silvered over, except 

 on outer web of outer primary: the inner half of inner webs sharply white, but 

 not reaching tip; rump, upper tail-coverts and tail (basally and centrally), white; 

 tail deeply forked, the outer pair of feathers elongated and narrowly tapering but 

 not, or barely, reaching the tips of closed wings ; their outer webs abruptly 

 grayish-dusky, contrasting with white of inner webs ; the succeeding pair also 

 similarly marked ; underparts white, tinged, except on throat and crissum, with 

 pale pearl-gray or lavender-gray: bill vermilion-red, blackening on tip: feet 

 orange-vermilion. Adidi in winter: Similar, but black cap imperfect, restricted 

 to hinder portion of head, (ir merely indicated ( ? ) ; imderparts pure white : bill 

 and feet not so bright. Young (in August): Forehead and lores ashy-grav ; 

 region about eyes, hind crown, and nape leaden black : back, scapulars and wings 

 pearl-gray, each feather tipped with brownish-buft and mingled subterminallv 

 with brownish-dusky, forming a strong bar ; upper tail-coverts and tail lighter 

 pearl-gray, the central feathers of the latter tipped with buffv: the anterior lesser 

 wing-coverts bluish-dusky, with narrow ashy edgings; edge of wing and quills 

 plumbeous-gray; underparts. white. Eengtli, 13.00-16.00 (330.2-406.4): wing 

 10.75 ^273) ; tail 5.00-6.00 ( 127-152. 4 ) ; bill 1.38 (35.1 ) : tarsus .80 (20.3). 



Recognition Marks. — Little Hawk or Crow size : black cap ; ])earl-grav 

 mantle: deeply forked tail: extensive white, or pale grayish plumage; graceful 

 flight. Knc>wn from the preceding species by outer pair of tail-feathers dark on 

 the outer instead of the inner weli; underparts not pure white in breeding season. 

 Bill tipped with black as distinguished from next species. 



Nesting. — Xot known to breed in Washington. .Vi'.?/.?.' in colonies, on beach 

 sliingle, or in grass of low islands, lined or not, with bits of bark, grass, etc. 

 Eggs: 2 or 3. rarely 4, very variable in ground color — light bluish or greenish, 

 dull white, stone, light olive, etc., spotted and blotched heavily, or not, with 

 blackish-brown or chocolate, and with lavender shell-marks. Av. size, 1.60 x 1.20 

 (40.6x30.5). Season: June : one brood. 



General Range. — Greater part of the northern hemisphere and .\frica. 

 In Xorth America, chiefly east of the Plains, breeding from the .Arctic Coast, 

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

 to A'irginia. Also coast of Lower California. Appallingly reduced in numbers 

 within recent years. 



Range in Washington. — Xot uncommon, sometimes abundant during migra- 

 tions, chiefly coastwise ; tarries localh- in September on lower Sound. 



Migrations. — Spring: c. Afay 15: Port Townsend, May 13, ii)o8 (1000). 

 Fall: August 25-Sept. 30. 



Authorities. — Dawson, AMlson Bulletin. Xo. 39, June 1902. p. 59. Also 

 specimens taken Blaine, Aug. 28, 1906. E, 



Specimens. — Prov. E. 



