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146 BRITISH BIRDS. 
Family STRIGIDA, 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, andthe Ducks. Forbes places them with the Goatsuckers, Rollers, 
and Bee-eaters, near the true Passeres. Gadow allies 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 affinities, 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. Hinder margin of sternum with two or more distinct fissures or clefts ; 
inner margin of claw on middle toe not serrated; middle toe longer 
than the inner one 
ie ee Conen wihh Si OpexO MUM », + is auis.y «5! fpa,>4 0 valde eee ae ge ae STRIX. 
b. Ear-conch without an operculum. 
a’. Nostrils placed in a projection formed by an inflation of the cere. Nocrua. 
b'. Cere not inflated. 
a>, Underparts white or barred transversely ; shaft-streaks and 
ear-tutis obsolete ornently 60... 01. un ast ee SURNIA. 
