94 BIRD BEHAVIOUR 



to one of these birds was also digested with its bones 

 and growing feathers. The Shag {Phalacrocorax 

 graculus) and the Indian Darter {Plotus melanogaster) 

 also digest their fish bones and all, but the Common 

 Cormorant {P. carbo) casts pellets. 



This habit of pellet-casting is another that needs 

 careful investigation ; unfortunately in many cases 

 it is necessary to keep the bird. in confinement to 

 ascertain these points about digestion, and in the 

 case of pellet-casting one has to be on the watch, 

 for the castings are not always thrown up every day. 

 In some cases a species may be exceptional among 

 its group, as in the case of the common Cormorant 

 above noted ; but commonly the casting of pellets 

 or otherwise seems to be a group-character. It is 

 very well-known among birds of prey, and the 

 falconers of old were well aware that to keep their 

 Hawks healthy it was necessary to provide them 

 with some indigestible material with which the 

 pellets might be formed, such as a tuft of wool 

 dipped in blood to make it palatable. 



The fish-eating birds of prey throw up pellets 

 as well as the flesh- and fowl-eaters ; so do the 

 Kingfishers, both the fishing ones and the land- 

 feeding forms like the Australian Laughing Jackass 

 (Dacelo gigas) ; so do Herons, Gulls, Rollers, and 

 Bee-eaters ; and among passerine birds, Shrikes, 

 Thrushes, Flycatchers, and no doubt others. But 

 the habit is not universal, and whatever may be 

 said about the impossibility of digesting chitin, I 

 have noticed no trace of insect remains among the 



