WHITE-TAILED PTARMIOAK. 
often the meann of t1it*ir flisroFerjr, ht this way lliey 
will often reach the oppoHiti; t^dgn af the rork, and 
w>ll» as il were, (iimuhaneouHly drop off; Imtthe ex- 
|>ectation of fiiulinp ihcm on some lower letfge will 
hfi (lisapjjouiled, fur tliey have perhaps liy that timo 
soijghl for ami reache<l the opposite side of the rooan- 
taiiiH, hy a low, wheeling fligfit, as noiseless as the 
eoUtudes hy whieh ihey are surruunded- The nest 
ia made ujider the rucks and stones, and is very diffi- 
cult to be found, for the female on pereeiviiig a person 
approach, generally leaves it, and h only discovered 
by her motion over the rnckf*, or her low chicking 
cry. III winter they debcejid lower, but seldom seek 
the plains. 
The only other bird beUmging to this interesting 
group is an American speden, disrovere*! by the ex- 
pedilifin under Captain riankliii. It has the habits 
or the rest, and inhahitH the Roekv Mountainit. It 
has been termed by Dr Richardson Lagopur Icttcttrus^ 
or White-tailed Ptarmigan, and is at once <liwiinguiiih- 
ed from any of the rest by the want of black on the 
pure winter plumage, wanting bodi ihe black eye- 
stripe and hlack taih «o eon^jiicuou^ in the others. 
The Rummer dreiia h intermediate in colour between 
that of the rock and common ptarmigan. 
