1886. | MR. R. COLLETT ON HYBRID GROUSE. 231 
1 Aarg. 2 B. p. 71 (Christiania, 1823), described a specimen in summer 
plumage which he obtained from Thoten (near the lake Mjésen in 
Norway). From the size of this specimen it appears to have been 
amale. The statement is as follows :— 
(Male? in summer (July)). ‘‘Caput, collum, dorsum, pectus 
Tetraonis tetricis famine. Remiges primores et secundarie albe, 
plurium tectricum albe. Rhachis remigis 1"° fusca. Rectrices 
nigre apicibus albis, duabus mediis nigris ferrugineo-undulatis ea- 
ceptis. Cauda non forficata. Abdomen et femora ut in T. tetrice 
femina, modo pennis singulis albis ornata, Digiti sublanati. Mag- 
nitudo T’, tetricis feemine.” 
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, Au 
inaccuracy has probably been made in describing the wings as white 
instead of “ whitish,” as in summer it is not likely that the white 
colour would be more extended than in winter; (and the description 
“ digiti sublanati”” 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 parts of Tetrao tetriv. I found a single spe- 
cimen, a male, in 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 plumage 
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 TZeérao tetriz. In the longer wing- 
coverts there 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 in the young of the 
Tetrao tetriz, 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 patches or broken cross bands). The under 
tail-coverts are barred by greyish white and brown as in Te¢rao 
tetrix. The throat is barred, but not so manifestly as the breast. 
