172 BRITISH BIRDS. 
forms, was named by Pallas Strixv egolius, and ranges from Archangel to 
Kamtschatka. It probably reappears in the Arctic regions of America ; but 
I have not been able to examine a skin of an adult male from that district. 
The so-called rufous “ phase” is the tropical plumage, which is known as 
Strix cassini, a climatic race, apparently most developed where there is a 
deficiency of sunshine and an excessive rainfall,’as in the Falkland Islands 
and the Hastern Himalayas. In this form the buff ground-colour is more 
rufous, and the brown spots and streaks are not so grey as in the typical 
form. In the females the difference between the two extreme forms is 
much less pronounced, and in the young in first plumage it is scarcely 
observable. The latter all belong to the rufous form, which we must 
therefore accept as the oldest, or least changed from the postglacial 
ancestors. In the Galapagos Islands the Short-eared Owls appear to have 
been so long isolated from their confréres as to have become specifically 
distinct. S. galapagoensis is said always to differ from the rufous form of 
S. brachyotus (which it otherwise greatly resembles) by having the legs 
streaked. It seems to be the only very near ally of this almost cosmo- 
politan species which is deserving of specific rank. 
The general colour of the typical form of the Short-eared Owl is dark 
buff. The wings and tail are transversely barred with dark brown; the 
rest of the plumage, except the thighs and under tail-coverts, is broadly 
streaked longitudinally with dark brown; bill and claws nearly black ; 
irides bright yellow. In the Arctic form the dark buff is replaced by 
nearly white, except in the centre of the back, which is suffused with 
rufous, 
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