THE WHITE-TAILED EAGLE. 173 



dark tips ; longer scapulars more uniform dark brown with purplish 

 tinge often mottled pale or whitish-brown ; longer upper tail- 

 coverts, more or less mottled with brownish-white or pale brown ; 

 feathers of lores bristle-like, black with short white tips at base ; 

 under parts much as upper-parts but often with more white especially 

 on breast where paler reddish-brown portion of feather is often 

 replaced by white more or less washed pale brown ; tibia and tarsus 

 more uniform dark brown ; tail-feathers with outer webs and tips 

 of inner webs black-brown slightly mottled whitish-brown, rest of 

 inner webs whitish-brown mottled black-brown ; wing-feathers as 

 in adults but proximal portions not so grey and shafts browner, 

 inner secondaries more or less mottled whitish-brown on distal 

 portions and innermost feathers pale brown with dark tips ; wing- 

 coverts much as upper-parts . 



First winter. — Like juvenile. 



First summer. — -A complete moult appears to take place 

 beginning Feb., new plumage appears to be like juvenile but tail- 

 feathers are slighly less mottled dark brown especially on inner 

 webs. 



Second summer. — Crown and nape intermediate between 

 juvenile and adult not so dark as former but not with brownish- 

 white tips of adults ; upper-parts much as adult but bases of 

 feathers white ; upper tail-coverts with a considerable amount 

 of white mottling ; under-parts as adult but with still more white 

 on basal part of feathers than in upper-parts ; tail much as juvenile, 

 but with rather more white ; new wing-feathers grey-washed as 

 in adult but inner secondaries mottled brownish-white. 



Third summer. — Insufficient moulting birds are available to 

 determine exact sequence of plumage and birds which are very 

 much like adults but have feathers of breast somewhat like juvenile, 

 feathers of crown not so white-tipped as adult and tail-feathers 

 (especially outer two or three pairs) with some black-brown at tips, 

 are probably in their third or fourth summer. 



Measurements and structure. — $ wing 57-65 cm. (measured 

 with tape, see vol. 1, p. *xni), tail 22.5-28 cm., tarsus 90-110 mm., 

 bill from cere 48-55 (14 measured). $ wing 61-68.5 cm. (one 

 Greenland 72), bill 50-62.5 mm. Primaries : 1st between 7th 

 and 8th, 3rd and 4th longest, 5th sometimes as long, sometimes 

 5-10 mm. shorter, 2nd and 6th 15-30 shorter ; 2nd to 7th 

 emarginated outer webs, 1st to 5th abruptly (and 6th much less so) 

 emarginated and attenuated on inner webs. Outer secondaries 

 shorter than 10th primary, inner ones becoming longer and longest 

 about equal to 7th primary, tips rounded. Tail rounded, two 

 central pairs about equal and longest, rest graduated, 12 feathers, 

 tips rounded. Tarsus feathered half-way down. Claws much 

 compressed, strong and curved, that of middle toe broadly grooved 

 on inner side. Upper mandible very large and deep, compressed, 

 curved and tip projecting beyond under mandible, which has 



