OWLS. 23 



tivity during the diminished light of the dusk or 

 night. They have the head very large, with 

 great, dilated, and projecting eyes, looking for- 

 wards, each surrounded by a concave disk formed 

 of singular diverging feathers. Behind these disk- 

 feathers is the opening of the ear, which in these 

 birds is of immense size, and of elaborate con- 

 struction. If we separate the feathers that form 

 the hinder part of the disk, we shall expose the 

 great ear enclosed between two valves of thin 

 skin, from whose edges these feathers grow, and 

 which are capable of being widely opened at the 

 will of the bird, to catch every sound that may 

 give notice of its prey amidst the silence and 

 darkness. The plumage is lax and downy, a 

 character that extends even to the wing-quills; 

 whence the flight of the Owls is unattended with 

 any sound produced by the striking of the air. 

 Even the outer primary has the barbs of its edge 

 separated like the teeth of a saw, allowing a pas- 

 sage to the air. The colours of the plumage are, 

 for the most part, sombre, consisting of various 

 tints of dull yellow, and brown, or white ; often 

 spotted, or minutely and most delicately pen- 

 cilled: a peculiarity of coloration that we find 

 in most nocturnal birds, and, by a beautiful ana- 

 logy, in the moths and sphinges among Insects. 



Mr. Yarrell observes, that from the loose and 

 soft nature of the plumage in these birds, as well 

 as their deficiency in muscle and bone, rapid 

 flight is denied them as useless, if not dangerous, 

 from the state of the atmosphere at the time they 

 are destined to seek their food ; but that they are 

 recompensed for this loss, partly by their acute 

 sense of hearing, from the structure of the ear 



