1032 DR.E. A. WILSON' ox THE [Junel4, 



Therefore not every bird tlmt gives this sign is necessarily a 

 bird of the year. 



The condition of the ends of the pi-imaries will, however, be a 

 fair indication of age, and especially of the two most distal 

 feathers. 



Another sign often used to test the age of a bird is the .strength of 

 the lower jaw. The w^eight of the bird is allowed to hang with- 

 out support by holding the tij) of the lower bill only. The bone 

 of an old bird's jaw eiusily stauils this test, but the soft jaw of a 

 voung bird of three or four months cannot carry its weight, and 

 the jaw either bends or breaks. 



Yet another test is often tried by trying to crush in the skull 

 with the thumb and finger : in the young bii-d the soft skull 

 gives way readily, in the old bird it retjuires very considerable 

 force. 



In judging at a moment's notice whether a young Grouse chick 

 which rises to the dogs on the 12th is of a shootable age and 

 gi-owth or not, the usual i-ule is probably as good a one as can be 

 foinid — namely, that there should be a very clear view of black 

 tail-feathers before the young bird is tit to kill. 



It is only necessary, however, to look at a few young Grouse 

 chicks of various ages to be convinced that moi'e than a little of 

 the black rectrices should appear before the bird is shot. Probably 

 m(!8t sportsmen will be guided better by the strength of the bird 

 upon the wing than by the black tail-feathers, however clearly 

 visiV)le 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 peV>ble shapes, and the reason for this 

 ha.s been fully discussed elsewhere. 



The question, therefore, as to whether a bird is less than a year 

 or more than a year old, may be answered, but it seems almost 

 impossible to judge more exactly the age of a bird by any sign 

 to be discovered either externally or internally, 



EXPLANATION OF PLATES LXXVIIL-CL 



Pl. LXXVIIL Pair of Red Grouse in summer with young chicks. 



„ LXXIX. Male grouse in full winter-pluuiage ; black type, underside. No. 723. 

 Perth sli ire, t.iv.07. 



„ LXXX. Male grouse, in full winter-plumage; red type, underside. No. 407. 

 Glendof, Iiivcrness->liir(>, T.xii.Ofi. 



,, LXXXI Male grouse, \vliito-si)otted bird of the red type; underside. No. 1377. 

 Morayshire, 2-4.iv.08. 17J oz. 

 'jXy.Xn. Male grouse, in full winter-plumage, red type carrying a few black- 

 centered feathers of the previous iiutunm-plumage ; upperside. No. 630. 

 Wales, 18.iii.07. 



,, LXXXIII. Male grouse, showing very markedly the beginning of the autumn- 

 plumage upon the bead and neck; upperside. No. 148L Invcrness- 

 >hirc, S.V.08. "JOozs. 



