
A Disease Outbreak in California Has Killed an Estimated 40,000 Birds
Avian botulism is a regular issue at the sprawling wetlands of the Klamath Basin Wildlife Refuges, but in a dry and hot year, it's gotten out of control.
Breeding adult male. Photo: Betsy Matsubara/Flickr (CC BY-2.0)
Mareca strepera
Conservation status | Settlement of the northern Great Plains may have reduced Gadwall numbers more than those of most ducks. Current populations vary substantially from year to year, but not in serious decline. |
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Family | Ducks and Geese |
Habitat | Lakes, ponds, marshes. In summer mainly around fresh or alkaline lakes in prairie regions or western intermountain valleys where land is open, not forested; also locally in coastal marshes. In migration and winter on marshes, lakes, estuaries, but generally not on salt water. |
Forages mainly while swimming by taking items from surface or by dabbling with head submerged, sometimes by up-ending, occasionally by diving. Rather seldom forages on land.
8-11, sometimes 5-13. White. 2 or more females sometimes lay in same nest. Incubation is by female only, 24-27 days. Young: leave nest shortly after hatching. Female leads young to water, where they find their own food; often seen on more open water than young of other dabbling ducks. Young are capable of flight 48-59 days after hatching.
Leave nest shortly after hatching. Female leads young to water, where they find their own food; often seen on more open water than young of other dabbling ducks. Young are capable of flight 48-59 days after hatching.
Mostly plant material. Feeds mainly on aquatic plants. Compared to other dabbling ducks, eats more leaves and stems of these plants, fewer seeds. Also eats small numbers of mollusks, insects, crustaceans, rarely small fish. Very young ducklings eat many insects at first before shifting to more vegetarian diet.
In one courtship display, male pulls head far back on shoulders and raises rear part of body out of water, with wingtips lifted to show off white patch in wing. Compared to most ducks, nesting begins rather late. Nest: female, accompanied by male, makes prospecting flights to seek site for nest. Site is usually near water, on dry land, surrounded by dense weeds or grass. Nest (built by female) is in a shallow depression, built of grasses, weeds, lined with down.
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Avian botulism is a regular issue at the sprawling wetlands of the Klamath Basin Wildlife Refuges, but in a dry and hot year, it's gotten out of control.
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