172 



BRITISH BIRDS. 



forms, was named by Pallas Strix agulius, 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 Eastern 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 confreres 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 brow r n ; 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. 



