THE ROCK-THRUSH. 423 



Adult female. Winter. Upper -parts like adult male winter 

 but paler brown with scarcely any tinge of slate-blue and feathers 

 of lower mantle and back only with dull buffish-white bases entirely 

 concealed ; upper tail-coverts paler orange -chestnut than in adult 

 male and with blackish subterminal bands ; lores buff to whitish ; 

 ear-coverts, sides of neck and sides of throat as male but with 

 bases dull slate-grey entirely concealed ; chin and centre of throat 

 pale buff to creamy -white ; rest of under -parts pale buff to orange- 

 buff (occasionally a few feathers orange -chestnut as adult male), 

 feathers tipped buffish-white and with brown -black crescentic 

 subterminal bands more numerous than in adult male but sparse 

 on centre of belly ; under tail-coverts, under wing-coverts and 

 axillaries paler than in adult male ; tail as male ; wing-feathers 

 and wing-coverts as male but not so dark brown and without any 

 bluish tinge on outer webs of primary- and greater coverts. Moult 

 as in male. (N.B. Abrasion has not a great effect as in male 

 but upper-parts become plainer brown by wearing off of many 

 pale tips.) Summer. Moult as in male. New plumage like old 

 but usually more chestnut on under -parts. Abrasion causes 

 feathers of head and mantle to show certain amount of slate and 

 back buffish-white. 



Nestling. (Not examined.) 



Juvenile. Male and female. Upper -parts much like winter 

 adult female but more buff, less brown and with grey bases of 

 feathers showing a good deal, feathers with dark brown tips as well 

 as penultimate bands ; under -parts buff, feathers fringed brown, 

 those of centre of belly and under tail-coverts uniform buff ; wings 

 and wing-coverts as female but browner and fringes and tips more 

 buff, median and innermost greater coverts and innermost second- 

 aries with a buff mesial spot. 



First winter. Male. Like adult male but upper-parts browner 

 not so blackish and bases of feathers not so blue, bases of scapulars 

 with less white ; wings browner and buff mesial spots on innermost 

 greater coverts and secondaries sometimes observable ; chin and 

 middle of throat whitish with only occasional slate-blue feathers ; 

 rest of under -parts rather paler chestnut than adult male. The 

 juvenile body -feathers, lesser and median wing-coverts and occa- 

 sionally one or two innermost secondaries and greater coverts are 

 moulted July-Sept., but not rest of wings or tail. Summer. Moult 

 as adult male, after which it becomes (especially when abraded) 

 impossible to distinguish with certainty but usually has browner 

 wings, longer buff tips to upper-parts and some feathers of under - 

 parts with black crescentic bands. 



First winter and summer. Female. Apparently impossible to 

 distinguish with certainty from adult female. 



Measurements and structure. $ wing 117-129, tail 6066 

 tarsus 26-29.5, bill from skull 23-25 (12 measured). 2 wing 1 14-123 



