black sea red data book - Department of Biology

Synonyms: None.
Mergus serrator (Linnaeus, 1758)
Common names: Engl: Red-breasted merganser; Russ: KrokhaV dlinnonosiy; Rom:
Ferestras; Turk: Sutlabi; Ukr: KrokhaV dovgonosy.
IUCN Status
World level:
Black Sea Regional level:
Subregion level: VU (Ukraine sector)
Distribution, Habitat type, Critical habitats, Limiting factors. An inhabitant of
brackish shallow waters and salinas. Breeding habitats include islands and spits with
dense, sometimes thinned-out grasses. Coastal reed-beds are preferred. Feeding
habitats are deep areas of bays and the sea.
Order ANSERIFORMES
Family ANATIDAE
Taxonomic description. NB - numerous, CB -common.
Biology. Mergus serrator is a partly resident, late-breeding species. Despite the early
display and fighting of the males, starting end of March, the first nests appear only by
late April. Clutches are laid at the end of May and can be found till mid July.
Incubation takes 30-32 days. Nests are made in the reed-beds (up to 43.3%) or
growths of Atripex tatarica and other shore vegetation. The species shows a strong
nesting conservatism: some females breed in the same locations annually. Clutch size
is 16-22 eggs; the larger clutches are either mixed or laid by two females. Hatching
begins in the second third of June, and fall brooding is in the last third of June.
Unfledged juveniles can be found till the second half of October. Can normally breed
anew after clutch loss, but clutch size is reduced to 5-8 eggs. Breeding habitats are
often destroyed by floods, which may wipe off parts of the shore. In cold winters
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