116 THE STARLINGS 



and down, to right, to left, and again is gone. At times it throws out 

 great shapeless feelers or "processes" that seem to palp the air for 

 unseen prey, or it floats at rest with long slow undulations, the last 

 evening rays sending shivering gleams along its flanks. At last, as if 

 unable to endure its own immensity, it rends itself in two. The masses 

 swing asunder, again to join, and it may be again to part. So the 

 great hosts range on till sunset, when sometimes in one mass, some- 

 times band after band, all the birds will rush, with a whirring of 

 wings, like a hurricane into the roost. 



The three most striking features of these remarkable displays 

 are the sudden changes in shape effected by each flock, the changes 

 in colour including those of light and shade, and the marvellous 

 simultaneity of movement to which both change in shape and colour 

 are due. That many thousands of starlings can by concerted orderly 

 movements suddenly alter the shape of the mass, or again by a swift 

 simultaneous alteration of the angle of the wings in regard to the 

 light alter its colour, so that, if this colour assimilates with the sky 

 behind, the whole flock vanishes almost instantaneously from view, 

 is in itself an astonishing fact, and grows none the less so when one 

 seeks the explanation. Unlike an army of men, the starling host 

 has no word of command or bugle-note, no known external stimulus 

 whatever to set it in simultaneous motion, yet its military precision 

 would shame a regiment of veterans. It is inconceivable that there 

 can be a leading bird, whose movements are watched and imitated ; 

 he would not be seen by large numbers, and even if he were, it 

 is equally inconceivable that his will should dominate thousands 

 to whom he was totally unknown. It may be that the starlings 

 possess some sense of which we know nothing, a spirit of the flock, 

 which moves them at one and the same time to act in one and 

 the same way, and which animates not only a flock, but a union 

 of flocks. This sense, if it exists, is by no means peculiar to 

 starlings, and is to be found more or less in all birds that are 

 gregarious. 



