About Lophodytes cucullatus (Linnaeus, 1758)
This species, the hooded merganser, is scientifically named Lophodytes cucullatus (Linnaeus, 1758), and it is sexually dimorphic. The adult female has a greyish-brown body, with a narrow white patch over the lower breast and belly. She has a light reddish-brown crest that extends from the back of her head. During the nonbreeding season, the male looks similar to the female, except that the male has yellow eyes while the female has brown eyes. In breeding plumage, the dorsal areas, head, neck, and breast of a mature mature male are mainly black with white markings. Large white patches sit on either side of the crest, and are particularly conspicuous when the male raises his crest during courtship. His lower flanks are a rich reddish-brown or chestnut colour, while the breast and undersides are more or less white, extending into white stripes across the crop and breast. In both sexes, there are narrow white stripes along the tertial wing feathers. When the bird is at rest, these stripes look like longitudinal white stripes along the bird's lower back, if they are visible. First-winter birds differ in appearance from adult females: they have a grey-brown neck and grey-brown upper parts, while the upper parts of adult females are much darker, almost black. Young birds also have narrower white edges on their tertial feathers than adult birds do. Females of all ages have dark eyes, while male eyes become pale during their first winter. The species' standard measurements are: length 15.8–19.3 inches (40–49 cm); weight 16.0–31.0 ounces (453–879 g); wingspan 23.6–26.0 inches (60–66 cm). Hooded mergansers are short-distance migrants, and they winter in the United States in regions where winter temperatures leave ponds, lakes, and rivers ice-free. They have two main year-round ranges. The first is in the eastern United States, stretching from the southern Canada–US border along the Atlantic Coast to the Gulf Coast in the Mississippi delta region. A smaller year-round range extends from Washington state and southern British Columbia to northern Idaho. They also breed to some extent in regions from Missouri to southern Canada, and from Nova Scotia to eastern North Dakota and Saskatchewan, migrating when necessary to avoid cold winter conditions. Between 1966 and 2015, the hooded merganser population saw a yearly increase of over 1.5% across its entire breeding range. Hooded mergansers prefer to live on small bodies of water such as ponds and small estuaries that have plenty of emergent aquatic vegetation, but they also inhabit larger wetlands, impoundments, flooded timber, and rivers. They prefer fresh water, but do also occur in brackish water bodies. The hooded merganser is a diving predator that mostly hunts by sight while underwater. Most studies note that its diet changes based on circumstances, and is usually dominated by fish, which make up 44–81% of its diet. It also feeds on aquatic insects, which make up 13–20% of its diet, and other aquatic invertebrates such as crabs and crayfish, which make up 22–50% of its diet.
