Page:The Zoologist, 4th series, vol 4 (1900).djvu/53

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ON THE MOULT AND COLOUR CHANGES OF
THE CORNCRAKE (CREX PRATENSIS).

By J.L. Bonhote.

Having for several years successfully kept, and on one occasion[1] bred, the Corncrake (Crex pratensis) in confinement, and having also had several wild caught specimens through my hands during the same period, the following results of my observations on the moult and colour change of this species may prove of some interest. In common with many other birds, the Corncrake has two moults in the year, the chief one taking place in July and August, as soon as the breeding season is over, and involving a change of every feather; the other taking place in February, while they are still in their winter quarters, and involving a change of all the feathers except the tail and wing quills. In the autumn moult the primaries and secondaries in both sexes are thrown off simultaneously, and for about ten days the birds are totally incapable of flight. On two occasions I have had wild birds brought in which had been captured when in this condition.

The males can be easily distinguished from the females during the summer months, as the breast, neck, and sides of the head are during that time of a delicate slaty grey colour. The plumage of the female hardly differs throughout the year.

At the autumn moult, however, the males lose the slate-colour on the breast and neck, and assume a plumage similar to that of the females.

The plumage assumed after the spring moult is precisely similar in both sexes to that which has just been discarded; in the male, however, the feathers on the breast and head, as soon as they are fully grown, begin to assume, by a change of colour, the bluish tinge of the breeding-season dress, and, as summer

  1. See Zool., 5th ser., vol. i., p. 35.