24- ACCIPITRES. 



their presence is of essential service, in removing 

 filtli, wliich would otherwise pollute the atmosphere. 

 Hence, in some countries, laws are enacted for their 

 protection, and they may be seen upon the roofs of 

 houses, or even frequenting the streets, where their 

 presence is not only tolerated, but encouraged. 

 Indeed, besides their usefulness when living, they 

 have an additional security in their utter worthless- 

 ness when dead. 



Vultures are gregarious, and often associate in 

 flocks of from twenty to thirty, or more, seeking in 

 concert the carrion upon which they feed. When 

 thus employed, they wheel in large circles that seem 

 to intersect each other, as if forming an immense 

 chain of rounded links, and thus inspect a consi- 

 derable extent of country. A flock of twenty can 

 in this manner easily survey an area of two miles. 

 Some fly at a considerable altitude, vfhilst others 

 keep near the ground, so that not a spot is left 

 unexamined. The moment a dead animal is dis- 

 covered, the lucky bird rounds to, and by the im- 

 petuosity ,of its movements attracts the notice of 

 its nearest companion, who immediately hastens to 

 share the feast, and is successively followed by all 

 the rest. Thus, the furthest from the discoverer, 

 although at a considerable distance, goes in a 

 straight line towards the spot indicated by the flight 

 of the others, as though attracted by an extraor- 

 dinary acuteness of smelling, erroneously attributed 

 to these birds. If the object discovered is large, 

 lately dead, and covered with a skin too tough to 

 be torn asunder, they remain about it, or linger in 

 the vicinity, perched on the dead branches of high 

 trees. In this conspicuous position they are easily 

 seen by other Vultures, who through habit well 

 know the meaning of such stoppages, and join the 

 first flock. Around the spot they remain, some 

 of them from time to time examining the dead 

 body, giving' it a tug in those parts most accessible, 

 until they find its putridity sufficiently advanced. 



