picture by J R Compton. http://www.JRCompton.com/photos/The_Birds/J/


When it comes to interactions with other organisms, Lesser Scaup tend to be quite social, laid-back ducks. Aside from early in their breeding season, when males are focused on protecting their partners, both sexes of Lesser Scaup are very tolerant of other birds of their species, called conspecifics, as well. In fact, at times they even work together with other Lesser Scaup such as during winter when they construct flocks as large as 500,000 during molting and migration. During the hours of daylight, the typical behavior of Aythya affinis can be described as quite active and tending to forage for about 20 minute increments at a time.

Much like any other species, one of the conflicts that Lesser Scaup do face is predation from other animals inflicted on them. Most predation is geared towards Scaup ducklings as they are more defenseless and therefore a better target than the adults, although predation of adults does occur as well. In attempt to shield their young from possible predators, female Scaup tend to keep the ducklings near the cover of vegetation. Potential predators to baby Scaup include black-billed magpies, great horned owls, American coots, Arctic loons, Swainsons hawks, and black-crowned night herons. Another form of predation on this species is for the predator to capture and feed on the actual eggs belonging to the females before they are even hatched. Some species that engage in this kind of activity include common ravens, California gulls, American badgers, raccoons, red foxes, crows, American mink, and ring-billed gulls. Many of these aforementioned species tend to prey on young ducklings as well. Adult Aythya affinis, on the other hand, do have a few of the same predators to worry about but also must beware of coyotes and skunks(primarily when located on their nests), along with peregrine falcons, snowy owls, red-tailed hawks, snapping turtles, and bald eagles.

Another form of interaction Lesser Scaup experience is parasitism with numerous species. In specific, a common parasite that many Lesser Scaup encounter, which is likely to lead to their demise, is trematodes. These are worm-like small intestinal parasites which require two intermediate hosts to complete their lifecycles, one of which must be snails. The means by which Lesser Scaup become infected with this parasite is by ingestion of these infected gastropods, seeing as how they are an important and large part of the ducks' diet, which then allows the trematode to infect and thrive in the intestine of the bird. Aythya affinis that fall prisoner to this parasite start becoming lethargic and struggle to continue flying and diving. It is common for the infected ducks to die around 3 to 8 days after ingestion of the infected snail usually due to blood loss and shock. Faucet snails, or Bithynia tentaculata, are a European species that have spread into the waters of Wisconsin including the Mississippi River and are a common host of these trematodes. Specific species of trematodes that are known to induce the aforementioned effects on Lesser Scaup include Cyathocotyle bushiensis and Sphaeridiotrema globulus, which is less than 1 millimeter long.

A second parasite that Aythya affinis, among other species, has been known to harbor is Eimeria aythyae. The oocysts of this single celled parasitic protozoan of vertebrates has been found to take up residence in the intestines of the ducks which in turn leads to destruction and sloughing off of the mucosa as well as hemorrhaging, or loss of blood.

Humans also have interactions with Aythya affinis in that they are a species that is legal to hunt for food at certain times of the year. As for sick Lesser Scaup, which may be infected with a parasite, humans are advised to avoid ingesting these birds. The parasites which occur most often in Lesser Scaup have not been found to affect humans, yet it is still highly suggested that the birds be cooked thoroughly before consumption.    

Read some interesting Aythya affinis facts at Interesting Facts
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