276 BIRD BEHAVIOUR 



gence is low ; unfortunately the higher in type 

 the mind of the bird, the more apt it is to be 

 indiscriminately vicious, as one may see in Parrots, 

 Crows, Weavers, and Sheldrakes. The Caracara 

 Carrion-Hawk (Polyborus brasiliensis) is also more 

 mischievous than other less intelligent birds of 

 prey ; I have even known one in the Calcutta Zoo 

 deliberately take any extra bit of food given him 

 up to the partition-bars separating him from an 

 Imperial Eagle (Aquila imperialist solely to enjoy 

 that bird's discomfiture at seeing food he could 

 not himself obtain. 



Some birds are so churlish that they like as a 

 rule to be alone ; such are the " nobler " birds of 

 prey Falcons and Eagles and most Thrushes, 

 especially the Robins and Nightingales ; it is to be 

 noted that these, the finest singers, are also the 

 most cantankerous, and their most thrilling music 

 is, it is to be feared, often only a " hymn of hate " ; 

 but at the same time, hen birds are undoubtedly 

 impressed by song, and canary-fanciers are con- 

 stantly being troubled by a hen bird " pairing by 

 the voice," and so upsetting any matrimonial 

 arrangements they themselves have made for her, 

 for no other suitor will be well received in such a 

 case until the favoured troubadour is out of hearing. 



It is quite a common thing to see affectionate 

 birds express their love for each other by fondling 

 each other's head with their bills, an attention 

 which human onlookers are apt to mistake for a 

 search for parasites. This is often a group- 



