FALCONID.E. 



69 



BUTEO VULGARIS. 



In the Common Buzzard the bill has a more lengthened form and is equally compressed 

 towards its tip, as in the Goshawk ; but it is more swelled out at the base, where it is covered 

 by cere. It is weaker ; the depth from the ridge to the cutting margin at the nostrils being 

 considerably less than in the latter bird ; in consequence of which, the hooked point is longer. 

 There is a conspicuous obtuse lobe on the cutting margin anterior to the nostrils. The lower 

 mandible is worn on its margin opposite this lobe, and is obliquely truncated at its end. The 

 nostrils, smaller and with more membranous margins than in the Goshawk, open obliquely 

 downwards, and have no central pillar. The anterior margin of the cere runs down to the 

 margin of the mandible opposite the nostrils. 



BUTEO LAGOPUS. 



The curve of the ridge of the bill of the Rough-legged Falcon is equal to that of the Gos- 

 hawk, and its cere is still shorter ; but the depth of the upper mandible at the nostrils is con- 

 siderably less, and it is destitute of a marginal lobe ; the rictus being almost quite straight from 

 the angle of the mouth to the sudden curve of the hooked tip. The nostrils are large, roundish, 

 and open obliquely forwards close to the margin of the cere. They are partially covered by 

 black hairs, proceeding from among the close white down which clothes the space between the 

 orbit and nostrils. The crown of the head is more convex than that of the Goshawk or 

 Common Buzzard. 



