1886.] MR. R. COLLETT ON HYBRID GROUSE. 231 



1 Aarg. 2 B. p. 71 (Christiauia, 1823), described a specimen in summer 

 plumage whic'i he obtained from Thoten (near the lake Mjosen in 

 Norway). From the size of this specimen it appears to have been 

 a male. The statement is as follows : — 



(Malel in summer (July)). "Caput, cullum, dorsum, pectus 

 Tetraonis tetricis foemince. Remiges primores et secundarice albce, 

 plurium tectricum albce. Rhachis remigis l"'^ fusca. Rectrices 

 nigrce apicibus albis, duabus mediis nigris ferritgineo-undulatis ex- 

 ceptis. Cauda non furjicata. Abdomen et femora ut in T. te trice 

 fcemintty modo pennis singulis albis ornata. Digiti sublunati. Mag- 

 nitudo T. tetricis foemince." 



The colouring of the summer plumage thus generally resembles 

 that of the Greyhen, but is distinguished by a few white feathers 

 on the abdomen. The tail-feathers also differ from the winter garb 

 in that the central pair are transversely banded with brown. An 

 inaccuracy has probably been made in descrilnng the wings as white 

 instead of " whitish," as in summer it is not hkely that the white 

 colour would be more extended than in winter ; (and the description 

 " digiti sublanaii " contradicts the possibility of the specimen being 

 a partial albino of the female Tetrao tetrix). 



Young Plumage. 



The plumage of the young is, as one might expect, mottled brown 

 like both parents, but the upper parts remind one more of Lagopus 

 albus, the lower |)arts of Tetrao tetrix. I found a single _ spe- 

 cimen, a male, iu this garb amongst a parcel of game from Oster- 

 dalen (South-eastern Norway) in the autumn of 1880 ; it had been 

 probably shot or captured at the end of September. The jjlumage 

 of the young on the whole is still retained, but a few winter feathers 

 have already appeared amongst the brown ; the wings and the outer 

 tail-feathers are also new, and belong to the winter plumage, and 

 thus present a striking contrast to the other mottled brown feathers. 



Young male in autumn (Plate XXII. fig. 1). — The upper parts 

 mottled and banded by rusty yellow and black, almost the same as 

 in the young of Lagopus albus, the cross bands being narrower and 

 closer than in the young of Tetrao tetrix. In the longer wing- 

 coverts tiiere is a discernible light elongated patch along the quills. 

 The tail-feathers, as in Lagopus albus, jun., are transversely banded 

 with black and reddish brown. 



On its lower parts the breast and sides, as iu the young of the 

 Tetrao tetrix, are closely and evenly banded with black and rusty 

 yellow, and both colours are about the same extent. In this respect 

 they more nearly approach the last species than Lagopus albus, as the 

 young birds of Willow-Grouse have the rusty brown colour much 

 more developed (so that the breast can be said to be a rusty yellow 

 with irregular black j)atches or broken cross bands). The under 

 tail-coverts are barred by greyish white and brown as in Tetrao 

 tetrix. The throat is barred, but not so manifestly as the breast. 



