Editing Greater scaup (section)

==Behaviour==

===Breeding===
[[File:Aythya marila MWNH 1032.JPG|thumb|Egg, Collection [[Museum Wiesbaden]]]]
Greater scaup breed in the tundra and the [[boreal forest]]; it is estimated that 75% of the North American population breed in Alaska. They typically nest on islands in large northern lakes. Greater scaup begin breeding when they are two years old, although they may start nesting at age one. Drake greater scaup have a soft, quick whistle they use to attract the attention of hens during courtship, which takes place from late winter to early spring, on the way back to their northern breeding grounds. Female greater scaup have a single pitch, a raspy "arrr-arrr-arrr-arrr-arrr" call note.<ref name="Greater Scaup"/> The courtship is complex and results in the formation of monogamous pairs.<ref name=Utahwildlife/>

Pairs nest in close proximity to each other in large colonies, usually near water, on an island or shoreline, or on a raft of floating vegetation. The nest consists of a shallow depression made by the female and lined with her down.<ref name="Birdweb" /> After the female lays the eggs, the drake abandons the female<ref name="Utahwildlife" /> and goes with other drakes to a large, isolated lake to moult. These lakes can be close to the breeding grounds, or distant, with birds performing a [[bird migration|moult migration]] of up to several hundred km, such as from northern Scandinavia to the [[IJsselmeer]] in the Netherlands.<ref name=BWP/> The lakes chosen are used yearly by the same ducks. The optimal moulting lake is fairly shallow and has an abundance of food sources and cover.<ref name="All about birds" />

The female lays six to nine olive-buff-coloured eggs,<ref name="Audubonbirds" /> which she [[egg incubation|incubates]] for 24–28 days.<ref name="Ohio.gov" /> A larger clutch could indicate [[brood parasitism]] by other greater scaups or even ducks of other species.<ref name="Fournier2001" /> The newly hatched ducklings are covered with down and are soon able to walk, swim, and feed themselves; however, they are not able to fly until 40–45 days after hatching.<ref name="EuropeBirdguide" /><ref name="Utahwildlife" /> The vulnerable small ducklings follow their mother, who protects them from predators.<ref name="Utahwildlife" />

===Feeding===
[[File:Aythya marila4.jpg|thumb|Flock feeding in Tokyo bay, Japan]]
The greater scaup dive to obtain food, which they eat on the surface.<ref name=Birdweb/> They mainly eat [[mollusc]]s, aquatic plants, and aquatic insects.<ref name="Greater Scaup"/> During the summer months, the greater scaup will eat small aquatic [[crustacean]]s.<ref name=Birdweb/> There is a report of four greater scaups in April near Chicago swallowing hibernating [[leopard frog]]s (a species with a body length about 5 centimetres, or 2.0 in), which they dredged out of a roadside freshwater pond.<ref name=Longley1948/> In freshwater [[ecosystem]]s, the greater scaup will eat seeds, leaves, stems and roots, along with sedges, pondweeds, [[muskgrass]], and [[Vallisneria americana|American eelgrass]].<ref name=DucksUnlimited/> Owing to the greater scaup's webbed feet and weight, it can dive up to {{convert|6–10|m|ft|sigfig=1}} and stay submerged for up to a minute.<ref name=Feeding/> In the past, they also often fed in winter in huge flocks on spent grain pumped offshore from distilleries (notably in the [[Firth of Forth]] in Scotland), but with modern pollution control, this food source is no longer available.<ref name=BWP/><ref name=Lack>{{ cite book |title=The Atlas of Wintering Birds in Britain and Ireland |editor-first=Peter |editor-last=Lack |first=L. H. |last=Campbell |chapter=Tufted Duck |year=1986 |location=London, UK |publisher=T & AD Poyser |page=112 |isbn=978-1-4081-3828-1 }}</ref>