Home Application Download FAQ
English
English
繁體中文
日本語
Español
Français
Deutsch
Pусский
Português
Italiano
한국어
Nederlands
العربية

Lesser Scaup

A species of Diving ducks
Scientific name : Aythya affinis Genus : Diving ducks

Lesser Scaup, A species of Diving ducks
Botanical name: Aythya affinis
Genus: Diving ducks
Lesser Scaup (Aythya affinis) Photo By silversea_starsong , used under CC-BY-NC-4.0 /Cropped and compressed from original

Description

Adults are 38–48 cm (15–19 in) long, 41.7–43 cm (16.4–16.9 in) on average. The species can weigh 454–1,089 g (1.001–2.401 lb); males weigh 820 g (1.81 lb) on average and weigh noticeably less, at 730 g (1.61 lb) on average. Wing lengths (not wingspans) are about 7.5–7.9 in (19–20 cm) in males and 7.3–7.8 in (19–20 cm) in females; the tarsus is about 1.4–1.5 in (3.6–3.8 cm) long, and the bill 1.4–1.7 in (3.6–4.3 cm). The wingspan is 68–78 cm (27–31 in). The adult males (drakes) in alternate plumage have a black, iridescent head and a small tuft at the hindcrown, a black breast, a whitish-grey back and wings with darker vermiculations and black outer and greyish-brown inner primary remiges. The underparts are white with some olive vermiculations on the flanks, and the rectrices and tail coverts are black. Adult females (hens) have a white band at the base of the bill, often a lighter ear region, and are otherwise dark brown all over, shading to white on the mid-belly. Drakes in eclipse plumage look similar, but with a very dark head and breast, little or no white on the head and usually some greyish vermiculations on the wings. Immature birds resemble the adult females, but are duller and have hardly any white at the bill base. Both sexes have white secondary remiges, a blue-grey bill with a black "nail" at the tip and grey feet; the drakes have a bright yellow iris, while that of females is orange or amber and that of immatures is brown. Downy hatchlings look much like those of related species, with dark brown upperparts and pale buff underparts, chin, supercilium and back spots. These birds are not very vocal, at least compared to dabbling ducks. Hens give the namesake discordant scaup, scaup call; in courtship drakes produce weak whistles. Hens vocalize more often than those of the greater scaup—particularly during flight—but their call is weaker, a guttural brrtt, brrtt.
Size
38-46 cm (15-18 in)
Colors
Brown
Black
Green
Gray
White
Life Expectancy
18 years
Nest Placement
Ground
Clutch Size
6 - 14 eggs
Incubation Period
1 brood
Number of Broods
21 - 27 days
Feeding Habits
Lesser Scaup primarily consume aquatic invertebrates like mollusks, insects, and crustaceans, as well as aquatic plants and seeds. They typically forage in shallow waters, diving and using their feet to propel. They employ a feeding technique where they insert their bill into mud, rapidly opening and closing it to capture prey.
Habitat
Lesser Scaup primarily dwell in freshwater wetlands, including marsh ponds, lakes, and the prairie pothole region, favoring areas with abundant emergent vegetation. These birds are also found in brackish environments like estuaries and coastal bays, particularly outside their breeding season. Lesser Scaup select habitats spanning from sea level to boreal forests and tundra zones, adaptable to various altitudes and climates. Vegetation in their habitat ranges from aquatic plants in wetlands to the grasses of prairies and hayfields.
Nest Behavior
Lesser Scaup begins egg-laying before nest completion, with nest-building concurrent with laying. Females manage egg and brood care, employing vegetation cover for concealment.
Nest Characteristics
Lesser Scaup's nest is a concealed ground depression amid tall vegetation like sedges, bulrushes, and cattails, or on floating vegetation. The saucer-shaped structure comprises grasses, plant materials, and downy feathers.
Dite type
Aquatic invertebrate eater

Migration Overview

Their breeding habitat is inland lakes and marsh ponds in tundra from Alaska through western Canada to western Montana; few breed east of James Bay and the Great Lakes. Notable breeding concentrations, with more than half a million birds at the height of the season, can be found in Alaska, in the woodlands of the McKenzie River valley and on the Old Crow Flats. These birds migrate south (mostly via the Central and Mississippi Flyways) when the young are fledged and return early spring, usually arriving on the breeding ground in May. Lesser scaup typically travel in flocks of 25–50 birds and winter mainly on lakes, rivers and sheltered coastal lagoons and bays between the US–Canada border and northern Colombia, including Central America, the West Indies and Bermuda. Wintering lesser scaup are typically found in freshwater or slightly brackish habitat and unlike greater scaup rarely are seen offshore when unfrozen freshwater habitat is available. They may even spend the winter on lakes in parks, as long as they are not harassed, and will occur even on smallish Caribbean islands such as Grand Cayman. Thousands winter each year on the Topolobampo lagoons in Mexico, and even in the southernmost major wintering location—Ciénaga Grande de Santa Marta in Colombia—hundreds of birds can be seen. In Central America, flocks are present from July on, but only really numerous after September. They move north again in April and May. In the extreme southeast and southwest of the breeding range—the Rocky Mountains region of the northwestern United States and the southern Great Lakes—lesser scaup are present all-year; it is not clear whether the breeding birds are replaced by migrants from the far north in winter, or whether the local populations do not migrate, or whether both local and migrant birds are found there in winter. They are rarely—but apparently increasingly often—seen as vagrants in western Europe. The first documented British record was a first-winter male at Chasewater, Staffordshire in 1987 but by 2006, over 60 had been recorded, with an average of 2 per year. UK records are typically in the northern parts of the country. Vagrant lesser scaup have also been recorded on the Hawaiian Islands Japan, possibly China, and—for the first time on 18 January 2000—in the Marianas, as well as in Ecuador, Surinam, Trinidad and Venezuela (in winter), and Greenland (in summer).

General Info

Behavior

Lesser Scaup exhibit distinctive diving behavior to forage, unlike dabbling counterparts. They sleep on water, often tucking their bill into back feathers for warmth. Highly gregarious outside breeding periods, lesser Scaup mingle with similar ducks. Their courtship is elaborate, with males performing wing flicks, head tosses, and sleek feather presentation, while females respond with neck stretches and vocalizations. Typically monogamous and seasonally faithful, females display site fidelity for breeding unlike males. Notably tardy migrants, lesser Scaup delay their seasonal journeys until compelled by freezing conditions, and similarly are among the last to return northward after wintering.

Distribution Area

Their breeding habitat is inland lakes and marsh ponds in tundra from Alaska through western Canada to western Montana; few breed east of James Bay and the Great Lakes. Notable breeding concentrations, with more than half a million birds at the height of the season, can be found in Alaska, in the woodlands of the McKenzie River valley and on the Old Crow Flats. These birds migrate south (mostly via the Central and Mississippi Flyways) when the young are fledged and return early spring, usually arriving on the breeding ground in May. Lesser scaup typically travel in flocks of 25–50 birds and winter mainly on lakes, rivers and sheltered coastal lagoons and bays between the US–Canada border and northern Colombia, including Central America, the West Indies and Bermuda. Wintering lesser scaup are typically found in freshwater or slightly brackish habitat and unlike greater scaup rarely are seen offshore when unfrozen freshwater habitat is available. They may even spend the winter on lakes in parks, as long as they are not harassed, and will occur even on smallish Caribbean islands such as Grand Cayman. Thousands winter each year on the Topolobampo lagoons in Mexico, and even in the southernmost major wintering location—Ciénaga Grande de Santa Marta in Colombia—hundreds of birds can be seen. In Central America, flocks are present from July on, but only really numerous after September. They move north again in April and May. In the extreme southeast and southwest of the breeding range—the Rocky Mountains region of the northwestern United States and the southern Great Lakes—lesser scaup are present all-year; it is not clear whether the breeding birds are replaced by migrants from the far north in winter, or whether the local populations do not migrate, or whether both local and migrant birds are found there in winter. They are rarely—but apparently increasingly often—seen as vagrants in western Europe. The first documented British record was a first-winter male at Chasewater, Staffordshire in 1987 but by 2006, over 60 had been recorded, with an average of 2 per year. UK records are typically in the northern parts of the country. Vagrant lesser scaup have also been recorded on the Hawaiian Islands Japan, possibly China, and—for the first time on 18 January 2000—in the Marianas, as well as in Ecuador, Suriname, French Guiana, Trinidad and Venezuela (in winter), and Greenland (in summer).

Species Status

Although the lesser scaup has the largest population of any species of diving duck in North America, their population has been steadily declining since the mid-1980s, and reached an all-time low in the early 21sh century. During breeding bird surveys, lesser and greater scaup are counted together due to the impossibility of identifying the species unequivocally when large numbers of birds are involved. Lesser scaup are thought to comprise slightly less than nine-tenths of the scaup population of North America. In the 1970s, the lesser scaup population was estimated at 6.9 million birds on average; in the 1990s it had declined to about half that number, and by the late 2000s it is estimated at 3 million individuals or less. Due to the wide breeding range and the fact that the rate of decline, though remarkable, is still not threatening in respect to the enormous overall numbers, the lesser scaup is classified as a Species of Least Concern by the IUCN. An increase of the decline is liable to result in an uplisting to Near Threatened or even Vulnerable status. The causes for this stark—though not threatening yet—decline remain unknown. There are indications that the breeding success is decreasing, but why this is so remains puzzling. On one hand, pollution and habitat destruction, especially in the wintering regions, has certainly increased since the early-mid 20th century. On the other hand, the narrow time frame in which lesser scaup breed and raise their young may be tied to some specific ecological conditions—such as abundance of key food items—which shifted winterwards due to global warming, without the ducks being able to adapt. In this regard, it is alternatively or additionally possible that greater scaup, which may be increasing in numbers, is putting the lesser scaup under increasingly severe competition. However, it seems that greater scaup eats larger food items on average, and the species are sympatric in part of their range and presumably have been for millennium without any problems due to competition. The experience of the past as well as the reproduction rate—even if this is declining—suggests that hunting has no major impact on lesser scaup populations at present either. Also, the breeding habitat is mainly in regions little-used by humans; habitat destruction on the breeding grounds is also not considered to be problematic.
Lesser Scaup (Aythya affinis) Lesser Scaup (Aythya affinis) Photo By silversea_starsong , used under CC-BY-NC-4.0 /Cropped and compressed from original

Scientific Classification

Download Picture Bird
Identify any bird by photo or sound in seconds
Cookie Management Tool
In addition to managing cookies through your browser or device, you can change your cookie settings below.
Necessary Cookies
Necessary cookies enable core functionality. The website cannot function properly without these cookies, and can only be disabled by changing your browser preferences.
Analytical Cookies
Analytical cookies help us to improve our application/website by collecting and reporting information on its usage.
Cookie Name Source Purpose Lifespan
_ga Google Analytics These cookies are set because of our use of Google Analytics. They are used to collect information about your use of our application/website. The cookies collect specific information, such as your IP address, data related to your device and other information about your use of the application/website. Please note that the data processing is essentially carried out by Google LLC and Google may use your data collected by the cookies for own purposes, e.g. profiling and will combine it with other data such as your Google Account. For more information about how Google processes your data and Google’s approach to privacy as well as implemented safeguards for your data, please see here. 1 Year
_pta PictureThis Analytics We use these cookies to collect information about how you use our site, monitor site performance, and improve our site performance, our services, and your experience. 1 Year
Cookie Name
_ga
Source
Google Analytics
Purpose
These cookies are set because of our use of Google Analytics. They are used to collect information about your use of our application/website. The cookies collect specific information, such as your IP address, data related to your device and other information about your use of the application/website. Please note that the data processing is essentially carried out by Google LLC and Google may use your data collected by the cookies for own purposes, e.g. profiling and will combine it with other data such as your Google Account. For more information about how Google processes your data and Google’s approach to privacy as well as implemented safeguards for your data, please see here.
Lifespan
1 Year

Cookie Name
_pta
Source
PictureThis Analytics
Purpose
We use these cookies to collect information about how you use our site, monitor site performance, and improve our site performance, our services, and your experience.
Lifespan
1 Year
Marketing Cookies
Marketing cookies are used by advertising companies to serve ads that are relevant to your interests.
Cookie Name Source Purpose Lifespan
_fbp Facebook Pixel A conversion pixel tracking that we use for retargeting campaigns. Learn more here. 1 Year
_adj Adjust This cookie provides mobile analytics and attribution services that enable us to measure and analyze the effectiveness of marketing campaigns, certain events and actions within the Application. Learn more here. 1 Year
Cookie Name
_fbp
Source
Facebook Pixel
Purpose
A conversion pixel tracking that we use for retargeting campaigns. Learn more here.
Lifespan
1 Year

Cookie Name
_adj
Source
Adjust
Purpose
This cookie provides mobile analytics and attribution services that enable us to measure and analyze the effectiveness of marketing campaigns, certain events and actions within the Application. Learn more here.
Lifespan
1 Year
Download