The western marsh harrier (Circus aeruginosus) is a large harrier, a bird of prey from temperate and subtropical western Eurasiaand adjacent Africa. It is also known as the Eurasian marsh harrier. The genus name Circus is derived from the Ancient Greekkirkos, referring to a bird of prey named for its circling flight (kirkos, "circle"), probably the hen harrier. The specific aeruginosus isLatin for "rusty".
Formerly, a number of relatives were included in C. aeruginosus, which was then known as "marsh harrier". The related taxa are now generally considered to be separate species: the eastern marsh harrier (C. spilonotus) and the possibly distinct Papuan harrier(C. (s.) spilothorax) of eastern Asia and the Wallacea, the swamp harrier (C. approximans) of Australasia and the Madagascar marsh harrier (C. maillardi) of the western Indian Ocean islands.
The western marsh harrier is often divided into two subspecies, the widely migratory C. a. aeruginosus which is found across most of its range, and C. a. harterti which is resident all-year in north-west Africa.
The western marsh harrier is 43 to 54 cm (17 to 21 in) in length, has a wingspan of 115 to 130 cm (45 to 51 in) and a weight of 400 to 650 g (14 to 23 oz) in males and 500 to 800 g (18 to 28 oz) in females. It is a large, bulky harrier with fairly broad wings, and has a strong and peculiar sexual dichromatism. The male's plumage is mostly a cryptic reddish-brown with lighter yellowish streaks, which are particularly prominent on the breast. The head and shoulders are mostly pale greyish-yellowish. The rectrices and the secondary and tertiaryremiges are pure grey, the latter contrasting with the brown forewing and the black primary remiges at the wingtips. The upperside and underside of the wing look similar, though the brown is lighter on the underwing. Whether from the side or below, flying males appear characteristically three-colored brown-grey-black. The legs, feet, irides and the cere of the black bill are yellow.
The female is almost entirely chocolate-brown. The top of the head, the throat and the shoulders have of a conspicuously lighter yellowish colour; this can be clearly delimited and very contrasting, or (particularly in worn plumage) be more washed-out, resembling the male's head colours. But the eye area of the female is always darker, making the light eye stand out, while the male's head is altogether not very contrastingly coloured and the female lacks the grey wing-patch and tail. Juveniles are similar to females, but usually have less yellow, particularly on the shoulders.
Eretele de stuf (Circus aeruginosus)
Eretele de stuf (Circus Aeruginosus) este o specie rapitoare diurna prezenta mai mult in partea estica a Rezervatiei Biosferei Delta Dunarii. In Delta Dunarii cuibareste 25 % din populatia europeana de erete de stuf. In Romania este o pasare strict protejata.
Migreaza toamna tarziu pentru a petrece iarna in nordul Africii. Masculii sunt cei care pleaca primii, urmati de femele.
Femela este ciocolatie cu pete galbui pe cap si umeri, in timp ce masculul are spatele gri, cu abdomenul roscat. Eretele de stuf are coada lunga, pentru o manevrabilitate buna in timpul zborului. Vaneaza in spatii largi deschise.
Spre deosebire de alte specii de rapitoare, eretele cuibareste la nivelul solului. Prefera zonele compacte de stufaris si plaurii.
Eretele de stuf nu este specializat pe un anumit tip de hrana. Consuma specii dintr-un spectru larg al lantului trofic, de la amfibieni la reptile.
Specia este monogama, insa exista si cazuri de masculi poligami. Chiar si asa, puii nu sufera din cauza lipsei de hrana. Femela construieste cuibul, iar masculul ajuta doar la transportul materialelor. Perechea are cuiburi false pentru odihna. Intr-un sezon o pereche depune 4-5 oua, cu o rata de supravietuire de 40%. La o saptamana dupa eclozare, puii se ascund in stufaris.
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