° 'i9i5 J Tyler, Simultaneous Actio)/. 201 



Also, until I make the birds apprehensive by coming near them, 

 there is no flying off to cover and back as I have noted in Juncos 

 and Tree Sparrows. However, in this case there is no cover near." 

 These birds showed the same uneasiness, the same tendency to fly 

 in numbers from their feeding ground as noted in the House Spar- 

 row, but here, with no cover to retreat to, they merely started into 

 the air and at once settled quietly among the weeds. 



When House Sparrows and certain other birds of similar feeding 

 habits are assembled in flocks, they may act in two ways, — indi- 

 vidually and as a unit. When the}' act individually, we understand 

 their behavior well enough; they act much as we should under the 

 same circumstances; they are quite human. But when we see a 

 hundred birds acting as one, and watch them as, without warning, 

 they start on the instant and whir away like leaves in a gust of wind, 

 we must needs believe that some superhuman force is at work among 

 them. Can it be that, for a time, each of the hundred little brains 

 forms a part of a common mind which, ever watchful for danger, 

 only recognises it in the abstract and periodically drives the flock 

 to seek shelter? This hypothesis is consistent with the facts; it 

 would explain otherwise meaningless interruptions of feeding as well 

 as the instantaneous flights, without signal, of busily occupied birds. 



If such is the case, — if a subconsciousness of danger hangs over 

 each large flock while feeding, — the birds are, or seem to be, un- 

 influenced by it and unaware of it until, like an explosion, it throws 

 them all into the air; as if the common mind governed a single body 

 instead of a hundred. 



In addition to the sudden risings from their feeding grounds, birds 

 often display unanimity of behavior on other occasions. The 

 simultaneous action of birds in rapid motion is well illustrated by 

 closely-packed companies of flying Sandpipers. Each bird, when 

 the flock changes its direction, escapes collision with its neighbors 

 by turning at the same moment, in its tracks, so to speak. If a 

 flock of Sandpipers changed its direction as a train of cars rounds a 

 curve (each car swinging to one side only when it reaches the curved 

 portion of the track) simultaneous action in the^birds would not 

 be required; each bird in that case would follow the example of 

 the bird immediately in front of him. Flocks of Sandpipers, how- 

 ever, do not wheel in this way, or they do not always do so. Any 



