1886.] MR. R. COLLETT ON HYBRID GROUSE. 233 



again to his gun. The knowledge of its life and habits therefore 

 amounts to almost nothing, and no observations have been made iu 

 Norway which can give any information concerning its origin. 



The existence of this hybrid arises from the fact that both parents 

 not unfrequently inhabit the same localities. Thus Tetrao tetrix in 

 the southern valleys of the land, where most of these hybrids are met 

 with, regularly ascends to the elevated birch-forests on the mountains, 

 and establishes itself in the regions where Lagopus albus has its 

 proper home. On the other hand, but more rarely, Lagopus albus 

 descends and breeds in the upper portions of the conifer-woods, 

 where the other species is still to be met with in numbers. 



In the northern portions of the country, however, where both 

 species live almost at the same elevation above the sea, and still more 

 commonly share the same place of residence, the Tetrao tetrix on the 

 whole appears in much lesser numbers than the other species, and 

 the hybrids are here apparently more rare. 



It is not easy to understand the true reason for the pairing between 

 two species so different in their habits, appearance, and nature. One 

 of the specimens obtained in Norway was shot at a place (Saltdalen 

 in Nordland) where no want of mates of either species could be 

 observed in the neighbourhood. Connections of this kind are 

 repugnant to nature, and in many cases the only feasible explanation 

 is to be found in imagining a violent and irresistible desire to breed 

 out of the species. 



Concerning the question of the origin, it is first of all necessary to 

 find out whether one or two sorts of such hybrids exist — the one 

 bred between the male Lagopus albus and female Tetrao tetrix, the 

 other between the male Tetrao tetrix and female Lagopus albus^. 

 But as it is an established fact that all individuals hitherto found 

 (with us) of the Rype-Orre, if obtained at the same season of the year, 

 are on the whole singularly alike both in size and the colouring of 

 their plumage, their origin cannot be ascribed to more than one of 

 the two possible connections. 



When Prof. Nilsson in 1817, in his ' Ornithologia Suecica,' treated 

 of its descent for the first time, he mentions it (p. 303) as 

 " Hybridus a Tetrice patre et Tetr. subalpino femina " -. This 

 assumption that it is tlie male of Tetrao tetrix which has formed 

 an illegitimate connection with the female of Lagopms albus (as 

 it is also the Blackcock that with the female of Tetrao urogallus 

 produces the " Rakkelfugl "), has always been and is still gene- 

 rally accepted by most naturalists. Upon this theory it has 

 received the names: — Tetrao lagopoides, 'Nihs. Skand. Fauna, 1st 

 ed. (1828), and Tetrao lagopides, 2nd ed. (1835) ; Tetrao lagopodite- 

 tricides, Sundev. SvenskaFogl. p. 255 (186-?), (being the descendant 

 of Tetrao tetrix, mas, it had to bear its generic name) ; and, finally, 



^ A hybrid between Lagojpus mutus and Tetrao tetrix is rather improbable, 

 on account of the very difi'erent haunts of these species. 



- " Qui vera vidct {illas) vcirieiatcs, non diuiius duhitare fotest de libidine 

 Tefricis ad furtivos amores cum congeneribns institiiendos semper paratissima." 

 (Nilss. I. c.) 



Proc. Zool. Soc— 1886, No. XVI. 16 



