58 BRITISH BIRDS, WITH THEIR NESTS AND EGGS. 
assistance indicated. When in captivity many of the species never seem to 
require water either to drink or to bathe in. 
The food of Owls consists of rats, mice, voles, moles, bats, small birds, 
large moths and beetles, earth-worms, frogs, and fish. The larger Owls, such 
as the Snowy and Eagle Owls, devour, in addition to this dietary, fawns, ‘hares, 
rabbits, squirrels, grouse, and other winged game. 
Owls moult but once in a year, and are in their best plumage during 
the winter; their feathers do not possess any after shafts, as in the Falconide. 
In colour their plumage is generally brown, or reddish brown, mottled, barred, 
or vermiculated with various shades of brown, black, and grey, thus corres- 
ponding with the tints of their surroundings in the bark and trunks of trees, 
&c., and is protective, serving to conceal them from the notice of their prey. 
The male is smaller than the female, and there is, in general, no difference 
in the plumage of the sexes. Although Owls have the appearance of being 
large birds this is chiefly due to their mass of soft plumage; when they are 
handled it is at once discovered that their bodies are small in proportion to 
their apparent bulk, and that they are made up chiefly of feathers. 
The genera of Owls on the British list may be tabulated as follows :— 
I.—Owls that have an operculum to their ear cavities; these Owls are almost 
exclusively nocturnal. 
Strix, Linneus.—Facial disk large and complete, narrowing rapidly below the 
eyes towards the beak. Legs long, and clothed with downy feathers 
to the origin of the toes, which are covered above with a few 
bristle-like feathers; hind toe reversible; claw of the middle toe 
serrated on the inner edge. 
Asio, Srisson.—Facial disk complete. Auditory opening asymmetrical. Legs 
and toes feathered to the claws. Two tufts of feathers on the head 
more or less elongated. 
SyRNIUM, Savigny.—Facial disk large and complete. Head large and rounded. 
Legs and toes feathered. 
Nycrana, C. ZL. Brehm.—Facial disk large and nearly complete. Legs and toes 
thickly feathered. Auditory opening asymmetrical, the bones of the 
skull affected and differing on either side. 
II.—Owls that are without an operculum to their ear cavities: these Owls are 
either entirely or partially diurnal. 
ATHENE, /. Sow.—Facial disk not well defined. Legs long, covered with short 
feathers; toes covered above with bristles. 
