30 BRITISH BIRDS' EGGS. 



three to five in number, are white with a bluish tinge, and 

 sometimes spotted. Nidification commences towards the 

 end of March. 



STBIGDXE. OWLS. 



The nocturnal birds of prey constitute the third family of 

 the Rapacious Order, and their eggs are always nearly pure 

 white, occasionally having a slight bluish or greenish tinge 

 of colour, as among the Harriers. This family is charac- 

 terized by the large proportion of the head to the body, by 

 the size of the eyes, which are surrounded by a fringe of 

 feathers, and by their soft, downy plumage, so different 

 from the firm and sharply-cut feathers of the diurnal Rap- 

 tores. The hearing of the Owl is believed to be exceedingly 

 delicate, and the size of the eyes has an evident relation to 

 the small amount of light in which they are usually to be 

 employed; while the fringe of feathers which surrounds 

 them probably has for its object to prevent the interference 

 of light from the sides, above, or below, and to enable them 

 to concentrate their whole power of sight upon the object 

 directly before them. As the Owl secures its prey by steal- 

 ing upon it unawares, the soft and yielding character of the 



