BIRDS. 



53 



Order : Raptores (Birds of Prey). 



Upper beak hooked, covered with a skin (cere) at 

 its base ; four toes possessing strong claws, and pro- 

 vided with pads in their under side (Fig. 31) ; wings 

 powerful. Birds of prey live in pairs, and breed once 

 a year in nests composed of pieces of wood and 

 branches. The young are nestlings (p. 51). Sight 

 keen. These birds 

 feed almost exclu- 

 sively on vertebrates, 

 principally mammals 

 and birds. An idea 

 of their food can be 

 gained by examina- 

 tion of their " pel- 

 lets" — roundish baUs 

 composed of the in- 

 digestible parts of 

 their food, and dis- 

 gorged from twelve 

 to twenty hours after 

 feeding. Two groups 

 are distinguished — 

 diurnal and nocturnal birds of prey. The first 

 (Figs. 31, 32) have a laterally flattened head, eyes 

 directed laterally, and tolerably stiff feathers. The 

 nocturnal forms (" owls," Figs. 30, 33) have a large 

 head, flattened in front, with large eyes facing to the 

 front, soft plumage, and hair-like feathers on the toes, 

 of which two are directed forwards, one backwards, 

 and one outwards. The radiating feathers round the 

 eye constitute a " veil." 



Predominatingly harmful (from killing domestic 

 mammals) are the following species occurring in 

 Britain: the Sea Eagle (HaliaMtus albicilla), the 

 Golden Eagle (Aquila cJirysaetus), the Peregrine Falcon 

 (Falco peregrinus), the Merlin {F. OBsalon), the Hobby 



Fig. 31.— Head and Foot of Falcon. 



