(2244) Cygnus bewickii.
Cygnus bewickii Yarrell, Trans. Linn. Soc,,xvi, p. 453 (1850) (Yarmouth, England).
Vernacular names. None recorded.
Description. Of the Swans with yellow lores, Bewick's Swan is the smallest, seldom having a wing exceeding 532 mm.; indeed, Buturlin gives the greatest measurement of any bird measured by him as 520 mm. The bill is strikingly shorter than that of (?. cygnus, being seldom, if ever, over 94.2 mm., whilst it is, on the other hand, comparatively much deeper at the base, measuring up to 43.6 mm.; the diminution in depth, from forehead to tip, is also much more abrupt, so that the upper outline presents a concave appearance. The serrations of the upper mandible in the closed bill are visible over about two-thirds of the total length of the bill when viewed from the side. In coloration the yellow is restricted to a portion of the base above, never touching the nostril, and is nearly always well defined from the black in a clean, curved line enclosing the higher extremity of the hollow-in which the nostril is placed and thence extending back along the margin of the upper bill to the gape. The feet also are much smaller, the tardus generally being less than 110 mm., whereas in musicus it is generally over 115 mm., whilst Buturlin gives the smallest of his series of the latter bird as 115 mm.
Colours of soft parts. Iris brown ; bill, as described above, black with yellow bars ; legs and feet black.
Measurements. wing 515 to 530 nun.; tail 150 to 168 mm.; tardus 100 to 115 mm.; culmen 90 to 98 mm.; wing 475 to 525 mm.; culmen 84 to 95 mm. ( Witherby).
Distribution. Over Northern Europe and Asia as far East as the Lena Delia. In Winter it extend South into Central Europe and South Russia as far as the Caspian and in Asia as tar South as Persia, Northern India and Central West China, extending in some numbers as far West as Great Britain. The records of its appearance in South-East China and Japan probably generally refer to the next bird, minor.
Occurrences in India. (1) One by Mr. B. L. McCullock at Jacobabad, in Sind, on the 2nd of December, 3907. (2) A female shot by Major P. C. Elliot-Lockhart near Mardan, on the North-West Frontier, on the 30th of December, 1910.
Nidification. Bewick's Swan breeds from .Northern Russia to Western Siberia, where it meets and overlaps with Cygnus minor, both species having been found breeding together on the Lena River. The site selected is one in open tundra close to rivers or on islands in the rivers, the nest itself being similar to that of other Swans, a pile of all sorts of vegetable rubbish lined with down. The eggs are white but soon become stained a yellow-buff; the full clutch seems to be three or four but not much is yet known of the breeding of the Swan beyond what Buturlin has written. Twelve eggs average 104.1 x 66.4 mm.: maxima 114.0 x 69.1 and 109.0 x 70.1 mm. ; minima 99.1 X 65.1 and 101.8 x 64.6 mm.
Habits. Those of the genus. This Swan sometimes eats fish in addition to the usual food indulged in by Swans.