146 BRITISH BIRDS. 



Family STRIGIDiE, or OWLS. 



The Owls are a very well-defined group of birds, and are associated by 

 Sclater with the Cuckoos, the Parrots, the Birds of Prey, the Pelicans, the 

 Herons, and the Ducks. Forbes places them with the Groatsuckers, Rollers, 

 and Bee-eaters, near the true Passeres. Gadow aUies them with the Parrots, 

 the Birds of Prey, the Pigeons, and the Gallinaceous birds. Here, again, 

 our three authorities do not all agree as to any of the families which are 

 allied to the Owls, which I place as my second family, with the caution to 

 the reader that it may or may not be related to the families which precede 

 or follow it. 



To the ordinary observer the Owls appear to be closely related to the 

 Birds of Prey by the form of their bill and claws, and by the shape of 

 their eggs. They appear to be specially related to the Harriers by their 

 facial disks, to the Ospreys by their reversible third toes, and to the Eagles 

 by their feathered tarsi. It is difficult to believe that all these similarities 

 are accidental; and when we find such differences of opinion amongst 

 scientific men as to their true afiBnities, it is difficult to avoid coming to 

 the conclusion that the value of osteological, myological, and other internal 

 characters have been somewhat overrated. 



Owls only moult once in the year, and appear to accomplish their change 

 of dress in July and August. Birds shot from September to December are 

 in splendid plumage ; but in April, May, and June the plumage is often 

 very shabby and worn. 



The Owls are, perhaps, the most cosmopolitan group of birds. They are 

 represented in the most northerly point of the Arctic regions and on most 

 of the Oceanic Islands. The number of species and subspecies known is 

 about 200, of which at least 10 are recorded as British, which may be 

 generically separated as follows : — 



A. Hinder margin of sternum entire ; inner margin of claw on middle toe 



serrated ; inner toe about equal to the middle toe in length Aluco. 



B. flinder margin of sternum with two or more distinct fi.ssures or clefts ; 



inner margin of claw on middle toe not serrated ; middle toe longer 

 than the inner one 



a. Ear-conch with an operculum Sthix. 



b. Ear-conch without an operculum. 



a) . Nostrils placed in a projection formed bj' an inflation of the cere. Xocti'a. 

 h\ Cere not inflated. 



<r. Underparts white or IjaiTed transversely ; shaft-streaks and 



ear-tufts obsolete or nearly so Subnia. 



