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. 



PARUS C.ERTJI/EUS OBSCTJRUS Prazak, Orn. Jahrb., v, p. 246 (1894 



England). 



Parus caeruleus Linnaeus, Yarrell, i, p. 483 ; Saunders, p. 109 ; P. c. 



obscurus 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 yellow ; 

 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, inner secondaries tinged 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. 



