The Lesser Scaup - A "Scarce" Winter Visitor
Not to be confused with the “Greater,” the Lesser Scaup is considered a “Scarce” Visitor to Anguilla. Each year I see one or two birds during January and February. This year was a bonus seeing eight birds on East End Pond.
Birds of the World, my go-to source for all things bird, shares the following insight into the species:
“This medium-sized black and white diving duck is one of the most abundant and widespread of North American ducks. Its core nesting habitats are in boreal forests and parklands from central Alaska through Manitoba, and numbers of this species breeding in the Prairie Pothole Region have increased over the past several decades. Breeders favor large seasonal and small semipermanent wetlands and lakes with emergent vegetation.
This is a late fall migrant, one of the last waterfowl to leave an area at freeze-up. Throughout fall and winter, Lesser Scaup form large flocks on rivers, lakes, and large wetlands. Individuals also winter in estuaries and marine habitats of the Gulf and Pacific coasts, and large rafts of this duck have been observed wintering offshore in the Gulf of Mexico during some winters. Indeed, the wintering distribution of this Scaup is farther south than other Aythya species—into Mexico, Central America, Puerto Rico, and the Caribbean.”
“Adults are sexually dichromic most of the year. The male's breeding plumage is characterized by a slaty blue bill; black head with purple/green iridescence; black neck, breast, and upper mantle; white flanks and belly; gray-flecked lower mantle; and black vent and undertail region. The female is dark grayish-brown to chocolate brown with a white patch of varying size at the base of the bill (sometimes broken into patches of white); upperparts darker; wing coverts flecked with gray; bill dark gray. In all plumages of both sexes, outer webs of secondaries are largely white, producing partial wing-stripe across the trailing edge of the upperwing. Iris color in males is brilliant yellow, but in females varies with age from olive brown to olive or brownish yellow (Trauger 1974).”
The Lesser Scaup is often confused with the Greater Scaup because they are similar. I have never seen a Greater Scaup on Anguilla and none have been recorded in eBird.
The two species are distinguished as follows:
“Often difficult to distinguish in the field from the slightly larger Greater Scaup; differences center on the head and bill shape, along with the width of the nail at the tip of the bill. In addition, the posture of the Greater Scaup makes its head appear more rounded; Lesser Scaup typically hold their head higher, often showing a distinct bump or crown at the back of the head. The nail on the tip of their bill is generally 6 mm wide for adults and black coloration is generally restricted to the nail. However, Greater Scaup adults generally have a proportionately wider nail (>6 mm), a deeper bill, and have black at the tip of the bill extending outside the nail (Wilson and Ankney 1988).
In addition, there is difference in the wing-stripe that is apparent during flight; the white extends to inner 6 primaries on Greater Scaup, but generally only across the secondaries, with gray extending onto inner primaries, on Lessers. About 9% of individuals have intermediate wing-stripe characteristics, mostly those were male Lessers with more white than typical and female Greaters with less (Wilson and Ankney 1988). Females cannot be readily distinguished at a distance except by wing pattern, although female Lesser Scaup tend to have a darker head and only rarely have the pale patch on ear coverts that is found on many female Greater Scaup. Nelson (Nelson 1996) developed an index based on nail and bill width to separate the 2 species in hand at any age.”
I recorded this species on East End Pond during the 15th Annual Caribbean Waterbird Census. They spent most of their time in the company of a flock of Ruddy Ducks happily feasting on the pond weed at the western end. They add a bit of pizzazz to Anguilla’s winter waterfowl gang!
You can read the highlights of the Caribbean Waterbird Census from around the region on the Birds Caribbean Blog by clicking here. Thanks to the Birds Caribbean Team for including my work in this excellent piece.
So pretty. Thanks for this.