The Red-breasted merganser (Mergus serrator) is a diving duck, one of the many bird species originally described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae, where it was given the binomial name Mergus serrator. The Red-breasted merganser is also notable for being the fastest duck ever recorded. It attained a top airspeed of 100 mph (160 km/h) while being pursued by an airplane. This eclipsed the previous speed record held by a canvasback clocked at 72 mph (116 km/h).
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DiurnalDiurnal animals are active during the daytime, with a period of sleeping or other inactivity at night. The timing of activity by an animal depends ...
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CarnivoreA carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of a...
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PiscivoresA piscivore is a carnivorous animal that eats primarily fish. Piscivorous is equivalent to the Greek-derived word ichthyophagous. Fish were the die...
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NatatorialNatatorial animals are those adapted for swimming. Some fish use their pectoral fins as the primary means of locomotion, sometimes termed labriform...
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CongregatoryCongregatory animals tend to gather in large numbers in specific areas as breeding colonies, for feeding, or for resting.
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OviparousOviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
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PrecocialPrecocial species are those in which the young are relatively mature and mobile from the moment of birth or hatching. Precocial species are normall...
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WaterfowlWaterfowl are certain wildfowl of the order Anseriformes, especially members of the family Anatidae, which includes ducks, geese, and swans. They ...
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SemiaquaticSemiaquatic animals are those that are primarily or partly terrestrial but that spend a large amount of time swimming or otherwise occupied in wate...
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Pursuit predatorPursuit predation is a form of predation in which predators actively give chase to their prey, either solitarily or as a group. Pursuit predators r...
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Serial monogamySerial monogamy is a mating system in which a pair bonds only for one breeding season.
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FlockingFlocking birds are those that tend to gather to forage or travel collectively. Avian flocks are typically associated with migration. Flocking also ...
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ColonialColonial animals live in large aggregations composed of two or more conspecific individuals in close association with or connected to, one another....
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MigratingAnimal migration is the relatively long-distance movement of individual animals, usually on a seasonal basis. It is the most common form of migrati...
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starts withThe Red-breasted merganser has a spiky crest and long thin red bill with serrated edges. The male has a dark head with a green sheen, a white neck with a rusty breast, a black back, and white underparts. Adult females have a rusty head and a grayish body. Juveniles look similar to females, but lack the white collar and have smaller white wing patches.
Red-breasted mergansers breed across northern North America, Greenland, Europe, and the Palearctic. They are migratory and spend winter in coastal waters in the south. Red-breasted mergansers prefer to breed on freshwater lakes and rivers and also can use brackish water of estuaries, shallow bays, or inlets.
Outside of the breeding season, Red-breasted mergansers are social and form flocks that can reach 100 individuals. However, these flocks are smaller during spring migration than they are in autumn migration and in winter. Red-breasted mergansers feed during the day in shallow waters. They dive from the surface to pursue aquatic animals underwater, using serrated bills to capture slippery fish. When not breeding, Red-breasted mergansers are mostly silent but during courtship, the female gives a rasping 'prrak prrak', while the male gives a catlike 'meow'. In flight, the female makes a harsh 'gruk'.
Red-breasted mergansers are carnivores (piscivores) and mainly feed on small fish. They may also add to their diet aquatic insects, worms, crustaceans, and amphibians.
Red-breasted mergansers are serially monogamous and form pairs only for a period of one breeding season. They start to breed between April and June. Pairs can nest singly or in loose colonies. The nest is usually located near water; it is a shallow depression made with grass and lined with soft down. The female then lays 8-24 eggs and incubates them for about 28-35 days. The chicks hatch precocial; they are covered with down, their eyes are open and they can leave the nest within 24 hours. Fledging typically occurs at 60-65 days of age and the young become reproductively mature when they are 2 years old.
Although not considered threatened, populations of Red-breasted mergansers in some areas may be declining. The main threats include habitat loss through wetland destruction, exposure to toxins such as pesticides and lead, and becoming bycatch of commercial fishing operations. Anglers and fish farmers have also persecuted mergansers, which they regard as a competitors.
According to the IUCN Red List, the total population size of the Red-breasted merganser is around 495,000-605,000 individuals. The European population consists of 70,100-120,000 pairs, which equates to 140,000-240,000 mature individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List, and its numbers today are stable.
Social animals are those animals that interact highly with other animals, usually of their own species (conspecifics), to the point of having a rec...