BIRDS IN AUTHORITY 51 



it is among mammals. It appears to mc that the in- 

 stances given above are not of this kind. The spirit, 

 the motive, is different. Here tiie Ijird is seen to take 

 tlie mastersliip for the general good, and we can only 

 suppose that, with or without greater strength and in- 

 telligence than his fellows, he undoubtedly possesses a 

 keener sense of danger, or superior alertness, and a 

 larger measure of that helpful spirit without which wild 

 animals could not exist in a social state. The action 

 of the gander and of the trumpeter in driving their 

 fellows home in the evening must be regarded as similar 

 in its origin to that of the male swift when he hunts 

 his mate back to the nest and of the sand-martin I 

 observed chasing the females of the colony to their bur- 

 rows. In a lesser way it may be seen in any flock of 

 birds; they move about in such an orderly manner, 

 springing, as it appears to us, simultaneously into the 

 air, going in a certain direction, settling here or there 

 to feed, presently going away to another distant feed- 

 ing-ground or alighting to rest or sing on trees and 

 bushes, as to produce the idea of a single mind. But 

 the flock is not a machine; the minds are many; one 

 bird gives the signal — the one who is a little better in 

 his keener senses and quicker intelligence than his com- 

 panions; his slightest sound, his least movement, is 

 heard and seen and understood and is instantly and 

 simultaneously acted upon. So well and quickly is he 

 understood and obeyed that the fact of his leadership 

 or promptership is difficult to detect. Another mani- 

 festation of this same helpful spirit with which observers 



