Expedition to the White Nile. 253 



It also has a shrill single cry, which I took to be the call- 

 note. When perched^ it continually flirts its tail np and down, 

 like a Wagtail, but with a sharper motion. 



Sometimes the bird will hide in a thick bush and allow 

 you to approach it. But on these occasions it always keeps 

 well to the further part of the bush_, moving round as you 

 do the same, and then suddenly darting out at the opposite 

 side, so that it is generally well out of range before you know 

 it has left the cover. You may kick or beat the bush, but 

 nothing will move it until it decides to leave, which is almost 

 sure to happen when your attention is occupied by a thorn. 



Adult. Iris light brown ; bill dull yellow ; legs and feet 

 pale green. 



35. Crateropus leucocephalus (Cretzschm.). 



These birds were common wherever the bush was thick. 



They are always to be found in pairs or in small companies 

 of five or six, and, although most amusing to watch, are 

 exceedingly annoying. The slightest thing seems to frighten 

 them, whereupon their alarm takes a curious turn. They 

 do not fly sensibly away, but persistently follow the intruder 

 about and hurl at him a continual stream of the most 

 maddening, rattling alarm-notes. This noise is made up of 

 a long string of " churrs,^' lasting for half a minute or 

 so at a time, and so rapidly are the notes repeated that the 

 whole sounds much like a policeman^s rattle turned with 

 feverish anxiety. Moreover, the birds perform in company, 

 sitting on a bough side by side and touching one another. 

 Should the collector be so unlucky as to rouse five or six of 

 them to their highest pitch of wrathful terror, he may give 

 lap all hope of collecting in that neighbourhood for some 

 time. Luckily they are conspicuous birds, and so may be 

 easily seen and avoided. 



Adult. Iris bright yellow ; bill black ; legs and feet 

 greenish grey. 



36. Pycnonotus arsinoe (Hempr. et Ehr.). 



This Bulbul was everywhere exceedingly common, and we 

 were never without one or two of them in the trees over our 



