338 A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



Female. — Apparently not to be distinguished with certainty from 

 adult. 



Measurements and structure. — $ wing 163-180 mm., tail 70-76, 

 tarsus 30-33, bill from feathers 25-29 (12 measured). $ wing 150- 

 163, bill 23-26. Primaries : 1st narrow, pointed and more than 

 half longest primary- covert, 2nd and 3rd about equal and longest, 

 4th 5-9 mm. shorter, 5th 13-18 shorter, 6th 22-27 shorter ; 2nd 

 very slightly emarginated inner web, 3rd outer web. Innermost 

 secondaries equal or shorter than 5th to 7th primaries. Bill much 

 smaller than in B. c. clangula and nostrils nearer base of bilL 

 Feathers of hinder -crown and nape elongated in adult male. Other 

 structure as in B. c. clangula. 



Soft parts. — Bill (ad. <£) bluish -plumbeous, dusky on nail and 

 at base, (ad. $) dusky inclining to plumbeous at end and along 

 commissure ; legs and feet (ad. £ ) pinkish or lilaceous -white, 

 (ad. 9) dilute lilac -pink, joints and webs darker ; iris very dark 

 brown. 



Characters — No subspecies. Adult male distinguished from other 

 British ducks by small size, metallic blue -green and amethyst -purple 

 head and neck, broad white band across occiput and pied plumage ; 

 females and juvenile male by small size, dark brown head and neck 

 with oblong white patch on sides of head. 



Field -characters. — At distance male looks vivid black and 

 white ; female brownish, with white marks on head. Both sexes 

 identified by large white patch from eye to nape. In adult drake 

 this patch shows vividly, but in duck less distinctly, and without 

 aid of glasses bird might be mistaken for female Harlequin, and 

 possibly female Long-tailed Duck. Harlequin, however, has two 

 distinct white patches between eyes and base of bill ; whilst female 

 Long-tail looks much larger and appears whiter at all seasons. 

 Usually in flocks of 10 or 15. Dives in 1-2 fathoms. Average 

 duration of dive exactly 23 seconds (181 dives timed). (C. E. 

 Alford.) 



Breeding -habits. — Haunts wooded lakes and swamps with dead 

 trees near water. Nest. — In natural hole in trunk of tree or old 

 Woodpecker's hole, occasionally even in gopher burrow where no 

 tree-site available. No nesting material except light grey down 

 and a few feathers. Eggs. — Usually 7 or 8 but occasionally up to 

 10 or even 12, and sometimes as few as 2 only, perhaps second 

 layings ; colour creamy like old ivory, smooth and hard. Average 

 of 24 eggs, 51.6x36.8. Max.: 55x37 and 51.4x37.7. Min. : 

 49.4x35.9 and 51x35.5 mm. Breeding -season. — Latter half May 

 and early June ; sometimes early May. Incubation. — By female. 

 Period unknown. Single brooded. 



Food. — Probably chiefly animal. Stark records small red worms ; 

 Hatch mussels, small fish fry, minnows, etc ; Millais water-beetles 

 and small freshwater snails. Saunders also includes leeches, grasses, 

 and aquatic plants, and shrimps. 



