16 WILD LIFE IN THE TREE TOPS 



A rather quaint theory which has been put forward by an ardent present- 

 day oologist — who also happens to be a somewhat poor climber — is that the 

 most vigorous Rooks select and monopolize the highest points of the trees for 

 the nesting sites — so that the weakly down-trodden Rooks have to be satisfied 

 with the lower and more accessible branches. Consequently the largest 

 clutches are at the extreme tops of the trees ! The oologist therefore who 

 is a poor climber^ — or who suffers from vertigo — must needs content himself 

 with a poor show of Rooks' eggs ! The writer's experiences do not confirm this 

 theory. 



The ground beneath a Rookery is littered with the sticks which have been 

 dropped by the birds during the scuffles involved in the business of nest-build- 

 ing, as well as with the pellets which the birds have cast. The latter generally 

 consist of grasses, beetles' cases, fur, and so forth, and afford good evidence 

 of the Rook's taste. 



It is perhaps not generally known that Rooks, Crows, Herons, and Shrikes 

 share with the Hawks and Owls the ability to thus get rid of indigestible matter. 

 And in order to enlighten those who are not acquainted with this habit, it 

 might be well to explain here exactly what a casting is, and how a casting is 

 produced — for castings will be referred to in later pages, and it will be weU to 

 understand the exact meaning of the term. 



A casting or pellet, then, is composed entirely of the indigestible portions 

 of recent meals, and is thrown up and ejected through the beak, generally on 

 the morning following the day on which the food was consumed. 



If, for instance, a Kestrel should devour, let us say, some mice, on a par- 

 ticular day, it will, early the next morning, suddenly commence to work its 

 head and neck about in an uneasy strained sort of manner ; and with lowered 

 head and open beak will strive to throw up the casting. In a few seconds 

 its efforts are successful', and the pellet or casting which, in the case of a 

 Kestrel, is usually about the size and shape of an acorn, drops to earth. Upon 

 examination the casting will be found to consist of the fur and whiskers of 

 the unhappy mice of yesterday. By examining such castings, one may form 

 a very fair idea of what the bird concerned has been feeding on. 



Rooks cling to their breeding-sites with remarkable tenacity. Year after 

 year they return to the same clump of trees ; in fact, their constancy in this 

 respect is so marked that their presence is often associated with the fortunes 

 of the family whose permanence has, so to speak, coincided with their own. 



It is an ill day for the Hall, say the village wiseacres, when at the nesting 

 season the Rooks fail to put in an appearance, and until they estabhsh them- 

 selves bad luck will overtake the place, and will continue. 



Sometimes, however, tradition is openly defied, and the Rooks given 

 notice to quit. 



The following instance may serve to show how difficult it may be to 



