(2289) Mergus senator.
The Red-breasted Merganser.
Mergus serrator Linn,, Syst. Nat., 10th ed., i,p. 129 (1758) (Sweden). Merganser serrator. Blanf. & Oates. iv, p. 470.
Vernacular names. None recorded.
Description. - Male. Whole head, crest and a narrow line down the back of the neck black ; the posterior part of the head and neck glossed green; neck white; back black; lower back, rump and upper tail-coverts white and very dark brown in wavy lines; the bases of the feathers on the lower back brown and showing a good deal; tail dark grey, the feathers edged paler; the three outer primaries and the innermost secondaries dark brown ; the fourth primary white with a black base ; the next two or three the same but the black decreasing and from these to the longest secondary white with narrow black margins; greater and median coverts white ; edge of the wing and smaller coverts brown ; breast rather rich rufous-brown, the feathers more or less centred black; the sides of the breast under the shoulders of the wing black, with a patch of feathers white, merely margined with black; outer scapulars white, inner black; flanks and sides of breast finely vermiculated black and white or black and grey ; remainder of lower plumage white.
Colours of soft parts. Iris carmine or red-brown ; bill orange-red to deep vermilion, the edge of the culmen and nail black ; legs and feet orange-red to bright vermilion, the joints generally darker and sometimes dusky, the webs darker and dusky, the claws light grey, duller and browner at their bases.
Measurements. Wing, 244 to 252 mm., 217 to 231 mm.; tail 79 to 88 mm.; tarsus 40 to 45 mm.; culmen, 53 to 62 mm., 48 to 55 mm. Two adults obtained in India have wings approximately of 253 and 254 mm.
Weight, 1 3/4 to 2 1/4 lbs,, under 2 lbs. I have been able to obtain very few recorded weights and it is probable that many birds much exceed these figures.
Female. Lores and upper parts of head pale rufescent-grey with darker centres to the feathers; a faint supercilium dull rufescent-white ; a dark streak below the lores ; chin and throat rufescent-white ; remainder of head and neck dull rufous ; upper parts ashy-brown, most of the feathers edged paler; primaries and innermost secondaries dark brown ; outer secondaries and their co verbs white, the latter with brown bases : remainder of wing-coverts ashy-brown ; lower parts white ; the flanks mottled brown and white; under wing-coverts grey and white.
Colours of soft parts as in the male but all duller. The iris is brown or red-brown, sometimes dull carmine; the bill is duller, more orange-red with the culmen dusky over a greater area; the legs and feet are more orange-red and paler than in the male.
Male in eclipse plumage like the female but with the colours of the wing retained as in the breeding-plumage.
Young males are like the female but the general tint more brown and less grey. The crest is shorter and all the soft parts still duller in colour.
Nestling in down like that of the Goosander but rather dark and sometimes a richer brown above.
Distribution. The Northern Hemisphere, Greenland, Iceland, Faeroes, Scandinavia, Northern Russia and ? Northern Asia, its Eastern limits not being definitely recorded. In Winter it occurs in America, South to Lower California and Florida; Northern Africa, Central West Asia to North-East India, China and Japan. In India there are only four authenticated instances of its occurrence. The first specimen was obtained by Yerbury in the Karachi harbour in 1877; a second specimen was purchased in the Calcutta bazaar in December 1889 ; a third, a young male, was shot by Captain Macnamara near Pishin in 1908. The fourth was obtained at Khushdil in 1902. This is recorded in the Journal of the Bombay Natural History Society by Ticehurst, who adds : " A not uncommon visitor in small flocks to the Mekran coast, keeping much to the bays."
Nidification. The Red-breasted Merganser breeds during May and June, but a few birds lay in early July in the extreme North, whilst eggs, probably a second laying, have been taken in August. This duck, unlike the preceding, does not breed in hollow trees and never makes use of egg-boxes but constructs a rather large compact nest of moss, grass and other bits of herbage. The lining is of grey down, but this is not only used to surround and lie beneath the eggs but a good deal is also incorporated in the body of the nest. This is placed either in among dense cover of bushes, heather or long grass or, at other times, it is built in rabbit-burrows, holes in banks or cliffs or under overhanging boulders. The eggs are a much deeper buff than those of M. m. merganser and are often tinged with a drab grey occasionally they are tinged with dull olive-green, whilst, very rarely, they are of a pale creamy-buff. Two hundred eggs average 64.9 x 44.9 mm.: maxima 70.0 x 44.7 and 64.5 x 47.3 mm.; minima 60.0 x 45.2 and 65.0 x 40.3 mm. The duck sits very close and has the habit, very common among ducks, of evacuating over her eggs, if startled off them.
Habits. The habits of the Red-breasted Merganser are much the same as those of the Goosander, though it is more exclusively a sea bird and, even on migration, apparently seldom wanders far from the sea-coast. On the coasts of the Baltic, though it may be met with on small islands a considerable distance from the mainland, its favourite resorts are the deep inlets of the sea which meander far into the coast-line. These often have a dense fringe of reeds and little backwaters, silent and still, with weeds covering their surface. Here the Mergansers are common and many nesting-sites are given away by the sight of the male swimming up and down the coast whilst his wife sits on her nest somewhere not very far away. In flight, swimming and diving powers etc. they are quite typical of the genus and they are as destructive to fish as are the Goosanders.