VARIATION IN THE HABITS OF ANIMALS. 623 



Upon my return the following summer the number of jays had 

 increased and the conflict was much less one-sided. In June, 1891, 

 early the first morning after my return again to Burlington, I 

 heard on the lawn the screeching of a hen hawk. The English 

 sparrows shot in terror into the verandas and among the vines 

 upon the house. Upon inquiry, I was told that the hawks had 

 been chasing the sparrows all spring, and was assured by our col- 

 ored cook that " dis country am coram' to 'struction sub, when de 

 hawks come to town." I had never known of an instance where 

 hawks had entered a town several miles in area, and supposed 

 that they were made so bold on account of the attraction such 

 an abundance of sparrow food afforded. The cry of the hawk, 

 however, seemed shriller and more satanic than any hawk cry I 

 had ever heard before. Indeed, there was a suggestion of a 

 mocking laugh in these hawk screams. I wondered if this change 

 in tone was due to the new environment of the hawk, to the fact 

 that it was dealing with such helpless prey, or whether the cry 

 came from a hawk new to me. 



With these questions in mind I watched carefully for days, 

 without even catching a glimpse of the hawks, although they 

 screamed at intervals all day long among the trees. Each time 

 the demonic scream began the sparrows seemed almost paralyzed 

 with terror, and the hens would hustle their broods into the barn 

 or under the shrubbery. One day, while lying in a hammock 

 watching some sparrows devour a fallen apple, I was startled by 

 the screams of a hawk in the tree just above me. Upon looking 

 upward I discovered that my elusive bird was no other than a 

 blue jay. The fallen apple was abandoned by the sparrows in 

 their fright and the jay sought its nest in a tree near by. For 

 several weeks longer the blue jays always concealed themselves 

 in the trees before they gave their adopted yell, but later in the 

 summer they did not even take the precaution of alighting in the 

 trees before screaming, but sat boldly in view upon the fence, 

 screamed while in flight, and even followed the sparrows into 

 their retreat among the vines. In a few instances they destroyed 

 the sparrows' eggs or young. 



For a time the ability thus to imitate the hawk seemed to be 

 confined to the blue jays nesting upon this one lawn. Of'ttimes 

 these blue jays would rush to the rescue of other blue jays on 

 neighboring lawns. Eventually, however, other blue jays learned 

 the cry, and in the following summer I heard it on the other side 

 of the town some two miles or more away. The second summer 

 after this imitation of the hawk began, other native birds returned 

 in small numbers. The blue jays often made themselves cham- 

 pions of these returned exiles. The other birds, however, soon 

 learned to resist the English sparrow on their own account. 



