114 A PEACTICAL HANDBOOK OF BRITISH BIRDS. 



Juvenile. — Like adults but upper-parts and wing-coverts 

 much darker, very dark brown or brownish-black, each feather 

 With narrow edging of pale buff to rufous -buff, scapulars with more 

 prominent buff bars than in adult ; streaks on under -parts wider 

 and blacker than in adult ; tibia, vent and under tail-coverts buff 

 to rufous -buff not rust-red ; tail-feathers as adult but less slate, 

 central pair as well as rest with longer buff tips, rufous bars 

 encroaching on outer webs ; wing-feathers and primary -coverts 

 darker than adult and with pale buff tips. 



First winter. — Like juvenile but pale edgings to feathers of 

 upper -parts gradually become worn off. First summer.— The 

 juvenile body -plumage frequently commences to moult in April 

 and sometimes in March (i.e. when bird is nearly a year old) but 

 birds in May have often not begun and those in full moult in 

 August and later, judging by very worn state of old feathers, must 

 have been hatched in previous summer, i.e. a year or more old. 

 When this moult is complete bird is indistinguishable from adult. 



Measurements and structure. — £ wing 247 (one 240)-272 mm., 

 tail 130 (one 122)-140, tarsus 34-37, bill from cere 12.5 (one 11.5)-14 

 (12 measured). 9 wing 265-280. Primaries : 2nd longest, 1st 

 6-15 mm. shorter^ 3rd 12-16 shorter, 4th 30-38 shorter, 5th 48-60 

 shorter ; 2nd emarginated outer web and 1st very abruptly 

 emarginated and attenated near tip of inner web. Rest of structure 

 as in Peregrine. 



Soft parts. — Bill leaden-blue, tip bluish-black ; cere, gape and 

 bare skin round eye and legs and feet yellow ; iris dark brown. 



Characters and allied forms. — F. s. jugurtha (north-west 

 Africa) is slightly paler on upper -parts ; F. s. centralasice (Tur- 

 kestan) is slightly paler and slightly larger ; F. s.jahutensis (north- 

 east Siberia) is rather darker than typical form on upper -parts and 

 streaks on under-parts are dark ; F. s. streichi (south China) is 

 like typical form but smaller. None of these races is very clearly 

 separable. Hobby is distinguished from other British Falcons 

 by moustachial stripe, rufous vent, nuchal band, thickly streaked 

 under-parts and wing -formula. 



Field -characters. — Most sylvan of British Falcons ; confined to 

 well-wooded districts. At rest long wings, broad black moustache, 

 white under-parts with conspicuous longitudinal black streaks and 

 rusty thighs identify it at once. In flight, which is direct and 

 rapid, as befits a bird that habitually flies down dragon-flies, 

 Swallows and Martins, and, at times, even Swifts, long sickle- 

 shaped wings and comparatively short tail suggest form of a giant 

 Swift, but action is that of a Peregrine, alternate rapid winnowing 

 and gliding on stiffly extended wings. Cry a shrill chatter described 

 by Walpole Bond as a whistling repetition of " quir-ic." 



Breeding-habits. — Builds no nest, but takes possession of old 

 one of Carrion-Crow as a rule ; occasionally that of Magpie, Heron, 



