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BLUE-WINGED TEAL  Spatula (Anas) discors 38–41cm. Commonest winter

migrant duck in Costa Rica, found in varied wetland habitats, from lakes, small

ponds, and flooded fields to quiet rivers and salt ponds; locally in flocks of 100s.

Feeds mainly by dabbling and up-ending. Small and rather sleek, with yellowish

legs. Adult male distinctive (imm. male resembles adult by mid-winter); female

cold-toned with whitish spot at base of bill, dark eyestripe. Cf. much rarer

Cinnamon Teal, Green-winged Teal. SOUNDS: Male gives slightly reedy, piping

pseep; female a low quack. STATUS: Fairly common to locally common mid-Sep

to Apr in nw. lowlands, a few earlier and into May; small numbers can occur

elsewhere almost throughout, exceptionally to 3000m. (Breeds N America,

winters to n. S America.)

CINNAMON TEAL  Spatula (Anas) cyanoptera 38–41cm. Rare winter migrant to varied wetland habitats,

most likely to be found among flocks of Blue-winged Teal. Feeds mainly by dabbling and up-ending.

Small but rather stocky, with yellowish legs, relatively spatulate bill. Adult male distinctive (imm. male

resembles adult by mid-winter); other plumages similar to Blue-winged Teal but warmer brown overall

(beware other ducks stained rusty) with plainer face (no distinct dark eyestripe), more spatulate bill.

Female Northern Shoveler has bigger bill, white tail sides. Cf. Green-winged Teal. SOUNDS: Male gives

quiet crackling rattle, mainly in display; female a low quack. STATUS: Rare and irregular Oct–Mar in nw.

lowlands; exceptional elsewhere, mainly on Pacific slope. (Americas.)

NORTHERN SHOVELER  Spatula (Anas) clypeata 43–51cm. Winter migrant

to wetland habitats, from lakes and sewage ponds to marshes with open water,

salt ponds. Feeds mainly by dabbling. Note big head, long spatulate bill, orange

legs. Adult male distinctive; female identified by big bill (longer than head); also

note white tail sides. Imm. male resembles adult by late winter; many winter

males ‘messy,’ with whitish crescent forward of eyes. SOUNDS: Male gives low

muffled grunts; female a quiet quack. STATUS: Uncommon Oct–Apr in nw.

lowlands and Central Valley, rare and irregular elsewhere; to 1500m. (Holarctic;

winters to Cen America.)

SCAUPS (GENUS AYTHYA)

(2+ species). Diving ducks that occur as winter migrants; like

dabbling ducks, generally declining in Costa Rica as birds remain farther north in winter. Best identified

by overall size and shape, head and bill patterns, wing patterns in flight. Unlike dabbling ducks, patter

across water to takeoff. Mostly silent in winter, and spend much time sleeping.

LESSER SCAUP  Aythya affinis 38–43cm. Winter migrant to ponds, lakes,

other wetland habitats with open water; sometimes in flocks, occasionally 100s.

Note slightly peaked hindcrown (can sleek down when diving to produce

rounded head), blue-gray bill tipped black; broad white wingstripe on secon­

daries becomes pale gray on primaries. Male told from Ring-necked Duck by

pale gray back, plainer bill; female by head and bill pattern, white wingstripe.

STATUS: Uncommon to irregularly fairly common and local Nov–Mar (a few

from Oct and into Apr) in nw. lowlands and Central Valley, to 1500m; scarce

and irregular elsewhere. (Breeds N America, winters to n. S America.)

RING-NECKED DUCK  Aythya collaris 41–46cm. Winter migrant to ponds,

lakes, other wetland habitats with open water, often in more vegetated, less open

situations than Lesser Scaup. Note slender bill with white subterminal band,

relatively long tail; in flight shows broad, poorly contrasting grayish wingstripe.

Male distinctive, with black back (imm. male resembles adult by late winter);

female best told by grayish head sides with narrow white spectacles, diffuse

whitish patch at base of bill, wing pattern; cf. Lesser Scaup. STATUS: Uncommon

and local late Oct–Mar in nw. lowlands; very rare and irregular elsewhere.

(Breeds N America, winters to Cen America.)