GAD WALL 175 



Gadwall 



Chaulelasmus streperus 

 (Kou-le-laz-mus, stre-pe-rus) 



Colour Plates Nos. 10 and 11. Downy Young No. 33. Hybrid No. 36. 



SCIENTIFIC NAME 



Chaulelasmus, from Greek, chaulios, meaning protuberant, chauliodous, mean- 

 ing having protrusive teeth, and elasmas, meaning a layer, a plate, referring to 

 teeth of bill; streperus, Latin, meaning noisy. 



COLLOQUIAL NAMES 



IN GENERAL USE: Cadwall (also spelled gadwell, gadwale, sometimes shortened 

 to gaddy); grey duck. IN LOCAL USE: Blaten duck; canard gris (grey duck); chicka- 

 cock; chickock; creek duck; glissom duck; grey widgeon; prairie mallard; redwing; 

 shuttlecock; specklebelly; widgeon. 



DESCRIPTION 



ADULT MALE. WINTER PLUMAGE: Head, with low crest, pale brownish or 

 grey, marked with small dusky streaks and dots; crown, darker, sometimes washed 

 with chestnut; neck, pale brownish, finely stieaked with dusky, darker on hind- 

 neck; chin and throat, buffy or whitish, usually lightly flecked with brownish; bill, 

 bluish black, with usually trace of dull orange at base and along edge, shorter 

 than head; eye, reddish brown to dark brown. Body. Back, scapulars, sides and 

 flanks, dusky, finely vermiculated with buffy or whitish, longer scapulars narrow 

 and pointed, dusky, with cinnamon-orange margins; chest, greyish black, with 

 whitish or buffy crescent-markings, giving a scaled effect; rump, black with slight 

 greenish gloss; breast, white, with faint dusky marking at rear; belly, white, 

 mottled with faint dusky; feet, bright orange yellow, with blackish webs. Tail, 

 brownish grey, narrowly edged with whitish; upper and under coverts, glossy black. 

 Wings. Lesser coverts at edge of wing, brownish grey, finely marked with buffy, 

 remaining lesser coverts and middle coverts, chestnut, few black; greater coverts, 

 black, outer ones, greyed and margined with chestnut; primaries, brownish; 

 secondaries, inner ones white, central ones, black, outer ones, greyish with white 

 tips; tertials, pale greyish buff; lining and axillars, white. 



ECLIPSE PLUMAGE: The moult into the eclipse begins in early summer and is 

 at its height, probably, in August. The full-plumaged wing is renewed. The 

 eclipse plumage is a reproduction of that of the female except that the feathers 

 of the chest are more finely marked with transverse bars; the bill becomes like 

 that of the female, except that it is not spotted. 



AUTUMN PLUMAGE: In early autumn the male commences a continuous moult out 

 of the female-like plumage of the eclipse, into the full winter dress. The wing is 

 as in full plumage. In early stages the male may be identified by a scattering of 

 the vermiculated, grey feathers of winter plumage on the back and scapulars; also 

 by the appearance of new crescent-marked feathers on the chest, and black ones 

 on the tail-coverts; the bill still resembles that of the female, except that it is 

 not spotted. During October, gradually increasing numbers of grey back-feathers, 

 and of crescent-marked ones on the chest, become apparent. By November most of 

 the birds are in full winter plumage. 



