BLACK DUCK 



161 



bird and that the differences which exist between the two forms can be accounted 

 for by differences of age, sex, and moult. The oft-repeated arguments for and against 

 the division of the Black Ducks into two subspecies are summarized in the "Life 

 Story" below. 



In the following "Descriptions" the two forms of Black Ducks are dealt with 

 conjointly, and slight but distinct and noticeable differences in the plumages of the 

 sexes are noted. 



DESCRIPTION 



ADULT MALE. WINTER PLUMAGE: (Attention is called to the fact that the 

 plumage of this fully adult bird conforms to that which is generally ascribed to the 

 Red-legged Black Duck; note especially the colours of the bill and feet.) 



Head and neck, lighter than rest of body, creamy 

 whitish, streaked with dusky; crown, dusky, feathers 

 edged with lighter; a dusky streak from base of bill 

 through eye; (area at termination of dusky streak, and 

 area on sides of head at rear often show green irides- 

 cence); chin and throat, usually streaked with dusky; 

 bill, yellow, with olive tinge, almost orange yellow 

 in older birds, occasionally, as in female, ridge is 

 marked with dusky; eye, brown to dark brown. Body. 

 Feathers from sides of U PP er back > *pulars, chest, sides and rump, dusky 

 chest of adult male Black brown ' with cream y white or buff [ father-edgings; 

 Duck in winter plumage. lower back > with fewer > narrower, pale feather-edgings; 

 feathers of chest, particularly those of sides of chest, 



with central, U-shaped buff markings (these markings are V-shaped in female); 

 feathers of upper sides, with reddish-buff stripe on upper web, or with reddish-buff 

 U-shaped marking, usually incomplete at apex of U; feet, orange red to coral reel. 

 Wings. Coverts, same as scapulars; primaries, dusky, lighter on inner webs; secondaries, 

 with purplish-blue speculum, bordered in front and behind with black bars, and often 

 narrowly tipped behind with white; tertials, dusky gray, edged with buffy grey, outer 

 ones, black on outer web; lining, silvery white; axillars, white, sometimes with dusky 

 brown along shaft. 



POSTNUPTIAL OR ECLIPSE PLUMAGE: This plumage is acquired by a moult which 

 usually commences in May or June. The eclipse plumage resembles 

 the winter plumage except (a) the feathers of the sides of the 

 chest and of the sides are plain dusky, without the U-shaped buff 

 markings or stripes of the winter plumage, (b) the light feather- 

 edgings tend in general to be narrower, (c) the bill and feet are 

 much duller in colour than when in full winter plumage. The 

 annual moult of the wing-feathers takes place during this moult. 

 (The eclipse male, illustrated on Plate No. 7, was shot on July 

 11, 1940, at Fort Severn, Ontario, on Hudson's Bay.) 



Feather from side 

 of chest of male 

 in eclipse plu- 

 mage. 



AUTUMN PLUMAGE: In September the adult male commences 

 a moult of the body feathers, tail, and tertials, discarding the 

 plumage of the eclipse for the full winter plumage. The new 

 feathers of the sides of the chest appear with their U-shaped 

 markings. The colours of the bill and the feet progressively brighten to the more vivid 

 colours of winter. The full winter plumage is usually complete by the end of 

 October. (Note that by the end of October, when the moult is practically complete, 



