60 A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



July-Sept. Summer. — A complete moult takes place Jan. -Mar. 

 occasionally April. Plumage as winter. 



Nestling. — (Not examined.) 



Juvenile. — Like adults but usually rather browner on fore- 

 head and upper-parts and with more rusty tinge on wing-coverts, 

 primary-coverts and outer webs of primaries ; tail-feathers not so 

 black and white tips not so sharply defined. 



First winter. — Like adults except for primary-coverts, primaries 

 and tail which are apparently not moulted. The juvenile body- 

 feathers and wing-coverts are moulted Aug. -Sept., but material 

 available is insufficient to show exact extent of moult. 



Measurements and structure. — (J wing 138-156 mm., tail 136- 

 158, tarsus 22-27, bill from skull 28-30 (12 measured). ? wing 

 137-150. Primaries : 3rd longest, 4th rarely equal, usually 1-5 

 mm. shorter, 1st 50-58 shorter, 2nd 12-17 shorter, 5th 10-18 shorter ; 

 outer webs not definitely emarginated but narrowing slightly on 

 distal halves. Tail graduated, two central pairs about equal and 

 longest, 3rd pair 2-8 mm. shorter, 4th pair 17-30 shorter, outer- 

 most pair 40-62 shorter, 10 feathers, tips rounded. Bill rather 

 slender, broad at base, compressed at tip, curved and somewhat 

 arched, upper mandible overlapping at tip. Nostrils bare, oblong 

 without a prominent margin. No rictal or nasal bristles. Tarsus 

 feathered a little below the joint, toes slender, 2nd and 3rd (longest) 

 directed forwards and 1st (very short) and 4th backwards. 



Soft parts. — Bill above and tip of lower mandible blackish 

 horn-colour, rest of lower mandible and basal half of cutting edge 

 of upper mandible yellow ; legs and feet dusky slate -grey ; iris 

 dark brown ; eyelids lemon-yellow ; bare skin round eye greyish 

 in adult, pale yellow in young (Ridgway). 



Characters and allied forms. — C. a. occidentalis (western N. 

 America) is very slightly larger and has a slightly stouter bill. 

 Easily distinguished from common Cuckoo by its smaller size and 

 uniform coloration. 



Breeding-habits. — Not parasitic but builds very slight nest of 

 twigs, lined with grass, blossoms, moss, etc., among branches of 

 trees. Eggs. — Normally 3-4, sometimes only 2, or 5 to 7, greenish- 

 blue in colour, with characteristic cloudy marks and decidedly 

 paler than those of Black-billed Cuckoo. Average of 66 eggs, 

 30.2x22.9mm. Max.: 33.5x25.4. Min. : 27.9x21.3 (Bendire). 

 Breeding -season. — Rather late, more often early in July than in 

 June, but in southern States occasionally late in April. Single 

 brooded in north, but sometimes double brooded in south. Incuba- 

 tion. — About 14 days, chiefly by hen (Bendire). 



Food. — Mainly larvae of lepidoptera. Beal records from 21 stomach 

 examinations, 355 caterpillars, 18 coleoptera, 23 orthoptera (grass- 

 hoppers), 31 hymenoptera (saw-flies), 14 hemiptera, 6 diptera. 



