100 A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



r Nostrils horizontal, frill of feathers on crown and hind- 



J neck Neophron, p. 184 



1 Nostrils oblique, nearly perpendicular, no feathers on 



I crown and hind-neck Gyps, p. 181 



! Fore -head and lores with ordinary feathers and bristles 

 or bristly tips to feathers 4 

 Fore -head and lores with small scale -like feathers, no 

 trace of bristles or bristly ends Pernis, p. 175 



C Toes with sharp -pointed prickly scales beneath, feathers 



.] without aftershaft, outer toe reversible . . . Pandion, p. 178 



J Underside of toes not prickly, feathers with aftershaft, 



v outer toe not distinctly reversible ... 5 



/ Bill with sharp tooth on upper and corresponding notch 



on under mandible Falco, p. 100 



Bill festooned, but without sharp tooth on upper or 

 notch on lower mandible 6 



Tarsus feathered throughout Aquila, p. 130 



Tarsus bare or partially feathered, at least bare behind 7 

 _( Tarsus scutellated in front, reticulated behind . 8 

 \ Tarsus scutellated behind or feathered in front . 9 



( Tarsus very short, tail forked Milvus, p. 165 



I Tarsus long, tail even or rounded Circus, p. 146 



r Huge birds, larger than Golden Eagle, scales beneath 



9 J toes rough Haliceetus, p. 171 



{ Smaller than Golden Eagle, scales beneath toes smooth 10 



1st primary more than one inch longer than shortest 

 secondaries, tail less than three-quarters length of 

 wing Buteo, p. 137 



1st primary less than one inch longer than shortest 

 secondaries, tail three-quarters length of wing or 

 more Accipiter, p. 158 



10 



Family FALCONID.E. 

 Vomer touching maxillo-palatimim, ending in an oval swelling. 

 Both spina externa and interna well developed. Prsecoracoid 

 connected with claviculum. Eggs always heavily blotched and 

 spotted red. Only one genus. 



Genus FALCO L. 



Falco Linnaeus, Syst. Nat., ed. x, i, p. 88 (1758 — Type by subsequent 

 determination in Check-List N. Amer. B. : Falco subbuteo L.). 



Contains all real Falcons, including Peregrines, Merlins, 

 Kestrels, Iceland Falcons, etc., the various groups not presenting 

 sufficient characters for generic separation. Upper mandible 

 with sharp " tooth " and corresponding notch in lower mandible. 

 Nostrils free, round, with tubercle in middle. Second primary 

 longest, sometimes (Merlin) 2nd and 3rd, 1st or 1st and 2nd with 

 abrupt, strongly -marked attenuation before tip of inner web. 

 Tarsus almost entirely bare. Eggs yellow if held against light 

 Cosmopolitan. 



