1018 DR. E. A. WILSON ON THE [Juue 14, 



many that were not up to the average weight the month l)efore 

 will now he jn-actically normal and prohably indistinguishable 

 from healthy birds, were it not that their serious indisposition 

 of the preceding months has put them behind their fellows in the 

 matter of feather-change. 



In August, therefore, the Committee's collection of skins 

 contains a large number of examples of hen-birds showing 

 deferred moult and belated growth of feather. 



The noi-mal healthy hen (.! rouse in August has ah'eady put off 

 most of the bi-oad-barred spring-plumage feathers of her nesting 

 dress, and is very much like the cock-bird in appearance, with 

 the same dark red-brown vermiculate or fine-barred plumage 

 nnderneath, white-flecked or not, as the case may be, and above 

 with a mixture of feathers new and old. 



The legs and feet of a forwai'd hen are already showing quite 

 a fair growth of white feathers, and the nails have all been shed. 

 The claws are therefore short and rather soft and the transverse 

 sulcus or groove at the point of detachment is clearly marked. 



In the wings there may still be a number of primaries to be 

 changed. 



In the convalescent " piner," on the other hand, the case is 

 often very different. 



She has still a most deplorably bleached and weathered 

 breeding-plumage on her, with worn-out feathers, frayed or ragged, 

 often with saw-toothed edges, showing the diffei'ent effect of wear 

 and tear on the pale buff-[)igniented and black-pigmented parts. 



The bird in this belated })lumage has quite naked legs and feet 

 and long unshed nails, or may at the most be just showing the 

 points of a new growth of feathers through the skin ; and in this 

 state she is conspicuously shabby and ill to look upon in comparison 

 with the splendid plumage recently acquired by her healthy 

 sisters, Jind by the now almost univei-sally healthy cocks. 



But the point above all others to be remembered in this 

 connectitm is that this hen is convalescent, and still has a couple 

 of months of good food and good weather, as a rule, in which to 

 complete her convalescence before tlie winter comes. 



If the spring outl)refik of disease has been severe — that is, if the 

 general Aveather conditions of the preceding winter and early 

 spiing months have been such as to conduce to a heavy and 

 widespread infestment of the grouse with the microscopic larval 

 trichostrongylus — then both cocks and hens Avill be equally in- 

 fested. Bnt the breeding-season and the concomitant needs of 

 the two sexes are, from April onwards, quite distinct. 



The result of this is that there is often a large mortality of 

 cocks in April and in May, and a much less marlced mortality of 

 hens, probal)ly in the proportion of seven or eight cocks to one 

 lien, l)ut definitely occurring in the same two months. 



There is no great mortality from strongylosis in any other 

 Tiioiiths of the year. Yet, notwithstanding tins, after May the 

 cfjcks are suddenly relieved and lapidly recover, so that by August 



