THE BRITISH SONG -THRUSH. 401 



coverts with brown outer webs tipped yellowish -buff and black- 

 brown inner webs ; median coverts brown with large wedge 

 shaped yellowish-buff tips ; lesser coverts uniform brown. This 

 plumage is acquired by complete moult Aug.-Sept., occasionally 

 Oct. Slimmer. No moult. Abrasion makes upper -parts (except 

 crown) paler and slightly greyer, under-parts less buff and spots 

 less intense, tips of wing-coverts paler. 



Nestling. Down, golden-buff, fairly long. Distribution, inner 

 supra -orbital, spinal, humeral and ulnar (occasionally one or two 

 tufts on outer supra-orbital tract). Mouth inside golden -yellow, 

 no spots, externally flanges pale yellow. 



Juvenile. Like adult but feathers of upper-parts with dark 

 tips, those of head with faint narrow buff mesial streaks, those of 

 mantle with larger and conspicuous yellowish to pale buff centres 

 and those of scapulars with still more conspicuous and larger mesial 

 streaks ; rump and upper tail-coverts rather paler, sometimes 

 washed with buff, but with few and inconspicuous pale streaks ; 

 under-parts with smaller spots than in adult ; lower-breast an4 

 belly usually washed with buff ; flanks less olive than adult ; under 

 tail-coverts pale buff ; tail- and wing-feathers as adult, but inner 

 secondaries with very narrow yellowish-buff tips to outer webs ; 

 greater wing-coverts with larger yellowish-buff tips than in adult 

 and extending upwards as mesial streaks in varying number of 

 inner feathers ; median and lesser coverts as inner greater coverts 

 but with mesial streaks longer and more pronounced. 



First winter and summer. Like adults and only distinguishable 

 Avhen one or more of the inner juvenile greater coverts with a mesial 

 streak remains unmoulted. The juvenile body -feat hers, lesser and 

 median wing-coverts and three to five innermost greater coverts 

 are moulted July -Sept., occasionally Oct., but not wing- and tail- 

 feathers, primary -co verts nor rest of greater coverts. 



Measurements and structure. ^ wing 111-121 mm., tail IT 90,. 

 tarsus 31-35, bill from skull 20-23 (12 measured). 9 wing 111-121. 

 Primaries : 1st 6-13 mm. shorter than primary -co verts (in. 

 juvenile and 1st winter 1st primary usually larger and longer 

 than in adults), 3rd longest, 4th usually as long but sometimes 

 1-3 shorter, 2nd and 5th 3-6 shorter (but not often equal to each 

 other), 6th 12-18 shorter ; 3rd to 5th emarginated Outer webs. 

 Outermost tail-feathers 3-5 mm. shorter than rest, 12 feathers. 

 Other structure as in White's Thrush. 



Soft parts. Bill, upper mandible black-brown, lower with 

 brown tip and flesh-yellow base ; legs and feet pale flesh ; iris 

 dark umber. 



CHARACTERS AND ALLIED FORMS. For differences of T. ph. philo- 

 melus and T. ph. hebridensis see under those forms. Buff under 

 wing-coverts together with spotted under-parts distinguish it from 

 other species. 



