Habits and Hunting.--See the general discussion on waterfowl. 
17. Aythye affinie (yton) 
Lesser Scaup 
Other Nanes.-- 
Guatemalan: pato chaparro 
English: ecaup, bdluebill 
Status.-~The lesser scaup is reported to be a common migrant and winter resident. 
Description.--A medium-sized diving duck, sexes dissimilar. 
_ Adult male.--Winter plumage: Head and neck black with purple iridescence; upper 
pack black, lower back and scapulare grayish due to black vermiculations on white back- 
ground, rump blackish; back of neck extending low on breast, belly white, abdomen brown; 
wing brownish, secondaries and inner primaries with white speculum, making conepicuous white 
pand across back part of wing; tail and coverts blackish; bill grayish blue, with black 
nail, irie, legs and feet bluish to dusky, webs often blackish. 
Adult female.—--Winter plumage: Head and neck brown, cheeks lighter and a con- 
spicuous white area on face at base of bill; back dark brown; chest and sides grayish brown, 
lower breast white; wing with all coverts and primaries grayish brown, secondaries with 
white speculum, bordered behind with brown; tail dark brown: bill dark gray with indistinct 
ring of lighter gray near tip, nail blackish; iris yellowish; legs and feet dark bluish 
gray, webs darker, 
Meagurements.-- 
Length, 381.0-457.2 
Wingepread, 762.0 
Wing, 190.5-208.3 : 
Tail, 48,3-68.6 Female smaller than the male 
Tarsus, 30.5-38.1 
Culmen, 38.1-48.3 
Veight.-- i 
Male (112), 1 1b. 6 oz. to 2 lbs. 5 oz: av. 1 1b. 14 oz. 
Female (118), 1 1b. 3 oz. to 2 lbs. 2 o2.: av. 1 1b. 12 oo. 
General Distribution.--Breeds from the middle Mackenzie Valley and Lake Athabaska to western 
Ontario and south (east of the Cascades) to Oregon, Utah, and Nebraska: formerly to northern 
Tllinois. Winters chiefly from the southern United States south to Panamé and the West 
Indies. 
Distribution in Guatemala.--Recorded only at interior lakes but it undoubtedly frequents 
coastal waters during migration. 
Records.--Lake Amatitlan, 125, March 8, ap 350, January 29, 1947; up to 750 seen in a 
single day, March 14-16, 1947; Lake Atitl&n, common, March 5, 1942; May 1-2, 1946, and January 
31, 1947; Lake Atescatempa, 30 March 15, 1946. 
In literature it has been recorded from: Lake of Duefas and Atitld4n (Salvin and 
Godman). . 
Habite and Hunting.-~See the genera] discussion on waterfowl. 
18. Nomonyx dominicus (Linnaeus) 
: Masked Duck 
Other Names.--None known 
None known. 
Status.--The masked duck apparently is a very rare migrant or resident. 
Description.--Slightly smaller than the ruddy duck but similar in build: wing with a conspicu- 
ous white patch; male with most of head black; female with two dark stripes on side of head. 
Adult male.--A very small, chunky,cinnamon red diving duck with a long, spike 
tail; forward half of the head black, posterior part, neck and upper breast cinnamon red, 
lower breast and belly whitish; wings dark with speculum and part of coverts forming a 
conspicuous white patch. Bill smaller than that of ruddy, upper part pale blue, with 
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