holding the tip of the lower bill only. The bone of an old bird's jaw easily Lower
bill. stands this test, but the soft jaw of a young bird of three or four months cannot carry its weight, and the jaw either bends or breaks.
Yet another test often used is that of trying to crush in the skull with the Skull. finger and thumb; in the young bird the soft skull gives way readily, in the old bird it requires very considerable force. In judging at a moment's notice whether a young Grouse chick which rises to the dogs on the 12tth is of a shootable age and growth or not, the usual Tail
feathers. rule is probably as good a one as can be found — namely, that there should be a very clear view of black tail feathers before the young bird is fit to kill.
It is only necessary, however, to look at a few young Grouse chicks of various ages to be convinced that more than a little of the black rectrices should appear before the bird is shot. Probably most sportsmen will be guided better by the strength of the bird upon the wing than by the black tail feathers,, however clearly visible in a half-grown chick.
In dissection, the age of an old bird is apparent, perhaps as plainly upon the table as elsewhere. The fibrous tissues all toughen with age and use, and the bones become harder. The grits of the gizzard in an old bird seem to be larger and more worn into rounded pebble shapes, the reason for this has been discussed elsewhere.[1] The question, therefore, of deciding whether a bird is less than a year or more than a year old, is possible, but it seems almost impossible to judge more exactly of the age of an older bird by any sign to be discovered either externally or internally.
