SKETCHES IN THE SOUDAN 67 



or grass afterwards, it will not be touched, but only on one con- 

 dition that no crow or buzzard has previously caught a glimpse 

 of it. I have covered the intestines of a grolloched antelope or 

 gazelle with a thin layer of sand well out in the open, and 

 watched in vain for birds ; none came when it was thoroughly 

 hidden, and no keen eyes had been there to look on uninvited. 

 Birds flew over, but took no notice of it whatever, and yet only 

 a small part left exposed, they would have at once collected in 

 crowds. Now these birds always arrive in regular succession, 

 crows first, then buzzards, followed by various vultures, the 

 smaller ones first, the larger after, and lastly by the marabou 

 stork, as stated by Sir Samuel Baker. He thereon grounds his 

 theory that " every species keeps to its own particular elevation, 

 and that the atmosphere contains regular strata of birds of 

 prey"; who, "soaring in circles," are "watching with tele- 

 scopic sight the world beneath " ; " and, although they are 

 invisible from the earth, there can be no doubt that they are 

 perpetually hunting in circles within sight of each other. Thus, 

 should one bird discover some object upon the surface of the 

 earth below, his sudden pounce would be at once observed and 

 imitated by every vulture in succession. Should the vulture 

 nearest the earth perceive a body, or even should he notice buz- 

 zards collecting at a given point, he would at once become aware 

 of prey ; his rush towards the spot would act like a telegraphic 

 signal to the others, that would be rapidly communicated to 

 every vulture at successive airy stations." This, no doubt, is 

 the true explanation of the interesting phenomenon of the mar- 

 vellously rapid assembly of birds of prey at a carcass ; nobody 

 who has not witnessed the rapidity of their arrival after an 

 animal has been killed would believe it possible. The black-and- 

 white crow is nearly always, being nearest the earth, as Sir 

 Samuel Baker remarks, the first arrival. Should that species not 

 be in the vicinity, the buzzards will be the first ; but then, I 

 have noticed, more time has elapsed. Immediately after the 

 departure of man an attack takes place upon the offal, attended 

 by a good deal of fighting, pushing, and quarrelling; the 

 smaller have to wait until their bigger brethren have gorged 

 themselves, when often those who were the means of bringing 

 the latter to the feast find but little left as their reward. 



On we go once more, taking a straight line towards camp, I 



