140 A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



appears to take place from April to Nov. and is complete. After 

 this (i.e. when bird is about a year or more old) plumage appears 

 to be same as adult. 



Measurements and structure. — <$ wing 400-435 mm., tail 200-225, 

 tarsus 65-75, bill from cere 21-23 (12 measured). $ wing 420-455. 

 Primaries : 1st between 7th and 8th, 4th longest, 3rd as long or 

 5-15 mm. shorter, 5th 5-20 shorter, 6th 55-70 shorter, 2nd 35-50 

 shorter. Rest of structure as in Buteo b. buteo except that tarsus 

 is feathered to base of toes. 



Soft parts. — Bill dark horn, bluish at base ; cere and toes 

 yellow ; iris brown. 



Characters and allied forms. — B. I. pallidus (Siberia, Kamts- 

 chatka) has more white on upper-parts and purer white on tail 

 and under-parts ; B. I. sancti-johannis (N. America) is very like 

 B. I. lagopus but slightly smaller, dark markings usually blacker 

 and tail often more barred. Larger size, white base of tail and 

 tarsus feathered to toes distinguish B. lagopus from B. buteo. 



Field-characters. — A true 



Buzzard, its soaring flight and ^-s — ^ ^\ 



broad wings closely resembling c-S> """ '•• .• 



those of common species and ^^^ > .joO^ 3 



with a similar mewing cry, 7 1 



perhaps rather deeper in tone. 

 Distinguishable in flight by 

 a much whiter under-surface, 

 with dark shoulder patch and 

 primaries : tail looks trans- 

 parent white with conspicuous 

 black band at end. Consider- 



flhlp variation in nlnmaap hnt The Rough-legged Buzzard (B. lagopus), two 

 a Die Variation in plumage DUD common variations as viewed from below. 



has not white on head charac- (From a diagrammatic sketch by H. M. Wallis.) 



teristic of Osprey. (F. C.R.J.) 



Breeding-habits. — Breeds usually on shelf or recess in face of 

 rocks, but where undisturbed will nest on top of boulders or even 

 on ground, and in southern part of its range, often in trees. Nest. — 

 Usually large, built of sticks, heather, twigs, etc., mixed with turf, 

 cup being lined dry grasses, fresh shoots of pine, Vaccinium, and 

 lichen (Usnea). Eggs.— Normally 3-4, not infrequently 2 only, 

 and occasionally 1 . When food is plentiful clutches of 5 and even 6 

 occur, and there is reason to believe that 7 are met with rarely. 

 Colour white with spots and blotches, sometimes also streaks of 

 varying shades of reddish- or purplish-brown. Some very sparsely 

 marked ; others with cloudy patches and smears. Average of 

 110 eggs, 54.9x43.5. Max. : 62x49.5. Min. : 48x41 and 57.5X 

 40.5. Breeding-season.— Latter half May and early June, varying 

 according to latitude. Incubation.— Chiefly, at any rate, by female ; 

 period not precisely known. Single brooded. 



