THE BRITISH BLUE TITMOUSE. 231 



they appear to arrive in most seasons from mid-Sept, to mid-Nov., 

 and large immigrations were recorded end Oct., 1878 (corresponding 

 with a "■ rush " at Heligoland), in 1889, and Sept., 1901 {Birds Yorks., 

 I, pp. 112-113). No specimens of these migrants have, however, 

 been examined and identified as belonging to this form. 



Distribution. — Abroad. — From about lat. north 64° in Sweden 

 and 60° in Russia, throughout continental Europe, but replaced by 

 allied forms in Spain, on some of the Mediterranean islands and 

 Canaries, north-west Africa, Persia, and apparently east Russia. 



94. Parus caeruleus obscurus Prazak — THE BRITISH BLUE 

 TITMOUSE. 



Partjs c^ruleus obscurus Prazak, Orn. Jahrb., v, p. 246 (1894 — • 



England). 



Pants cceruleiis LinnaBus, Yarrell, i, p. 483 ; Saunders, p. 109 ; P. c. 



obsctirus Prazak, Hartert, Brit. B., i, p. 213. 



Description (Plate 9). — Adult male. Winter. — Fore-head, broad 

 stripe over eye joining narrow band at back of crown, white ; rest 

 of crown bright glossy blue ; hind-neck extending to base of sides 

 of neck dark blue ; nuchal spot bluish-white ; mantle, scapulars 

 and back green ; rump yellowish-green ; upper tail-coverts blue ; 

 line through lores and extending from eye to blue of nape, black ; 

 cheeks, ear-coverts and sides of throat white ; centre of chin and 

 upper-throat widening on lower-throat and meeting blue of sides 

 of neck black (most of the feathers tipped white) ; breast, flanks 

 and under tail-coverts yellow ; middle of lower-breast and belly 

 white, with patch of blackish-blue in centre ; axillaries pale yelkw ; 

 tail greyish-blue, central pair and outer webs of rest bright blue, 

 outer pair narrowly fringed white on outer web ; primaries and 

 secondaries black-brown, outer webs blue and inner webs narrowly 

 fringed white, 1st and 2nd primaries uniform black-brown, 3rd to 

 7th with distal emarginated portion of outer webs dull white and 

 basal half bright blue, imier secondaries tingtd greenish on outer 

 webs and tipped dull white ; primary-coverts blue on outer webs, 

 brown on inner with very narrow whitish tips ; greater coverts 

 same with broadish white tips ; median and lesser coverts blue. 

 This plumage is acquired by complete moult in Aug.-Oct. Summer. 

 — No moult. Abrasion makes blue of crown, wings and tail brighter 

 and black of throat more intense, and rather more extensive, white 

 tips of greater wing-coverts become smaller. 



Adult female. — Like adult male but not so bright, primary- 

 coverts and outer webs of secondaries more tinged with green, not 

 so bright blue. 



Nestling. — Down, greyish-white, rather short and scanty ; 

 distribution, inner supra-orbital, occipital and humeral. Mouth 

 inside dull orange-red, no spots ; externally flanges pale yellow. 



