706 A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



with white tips and inner webs, inner feathers with a dark grey 

 central patch ; upper lesser coverts dark grey tipped and fringed 

 ash-grey, forming narrower and paler line than in Arctic and much 

 paler than in Common Tern but sometimes this dark line is absent 

 and all lesser coverts are like rest of coverts pearly ash-grey as 

 mantle. This plumage is acquired by complete moult July-Oct.. 

 Summer. — Apparently moults as Common Tern but none in moult 

 examined. Head as Common and Arctic Terns but back of neck 

 white with slight grey tinge ; rest of upper -parts as winter much 

 paler and more pearly-grey than in Common or Arctic and rump and 

 upper tail-coverts paler grey but not white ; whole under -parts 

 white with strong rose blush in life (varying in strength and dis- 

 appearing in most skins) ; tail- and wing -feathers as winter ; all 

 wing-coverts as mantle. 



Nestling (Plate 10). — Differing from nestlings of Common and 

 Arctic Terns by coarse or matted appearance of down, this being 

 caused by a number of filaments of down being joined together in a 

 common sheath at the tips* as they are at the extreme base, tips of 

 white down on breast and belly are, however, separate and normal. 

 Whole upper -parts, sides of head, chin, and throat varying grey 

 tinged buff to rich buff with base of down brown-black and some 

 here and there entirely black, giving a speckled appearance with no 

 definite pattern ; breast and belly white. 



Juvenile. — Fore -head and lores freckled brown, each feather 

 having a brown tip fringed white ; top of crown streaked brown, 

 black, and white ; nape and ear-coverts brown-black, feathers 

 narrowly fringed whitish ; back of neck white, more or less freckled 

 brown ; mantle pale blue-grey, feathers with brown-black crescentic 

 bars at tips ; upper scapulars with a double bar divided by whitish 

 patch ; lower scapulars with long white tips without bars ; back, 

 rump, and upper tail-coverts ash-grey, sometimes faintly mottled 

 brown ; black spot in front of and black speckles under eyes ; rest 

 of under-parts white ; tail : outer pair white on both webs, next 

 two pairs with outer webs dark grey with fine blackish line near tip 

 and inner webs white, next two pairs with ash-grey outer webs and 

 dark brown band at tip, inner webs white, central ones ash-grey on 

 both webs with dark brown crescentic bar at tip ; wing-feathers aa 

 adult but darker grey, and grey-black line along shafts of outer 

 primaries wider, but white on inner edge extended to tip as in adult, 

 innermost secondaries barred as upper scapulars ; greater and 

 median coverts pale blue -grey, tipped whitish and with faint brown 

 subterminal f recklings ; lesser coverts dark grey fringed whitish. 

 N.B. — As compared with S. h. hirundo and paradiscea fore-head 

 freckled not white or buff, crown more streaked, bars on upper- 

 parts blacker, outer tail-feathers white not with blackish outer webs, 



* Whether these sheaths are retained throughout the downy stage %. 

 cannot say, as the only nestlings of this species available for examination are 

 very young ones. — H.F.W. 



