52 ADVENTURES AMONG BIRDS 



simultaneously acted upon. So well and quickly is 

 he understood and obeyed that the fact of his leader- 

 ship or promptership is difficult to detect. Another 

 manifestation of this same helpful spirit with which 

 observers of wild animals are familiar, is seen in the 

 self-appointed guardian or sentinel of the feeding or 

 sleeping flock. In some mammals it appears in a 

 striking way, as in the guanaco on the Patagonian 

 plains, when one member of the herd ascends a hill 

 or other high spot to keep watch while his fellows are 

 browsing on the bushes or grazing on the plain below. 

 In some birds the watchful spirit is so powerful that 

 the sentinel and alarm-giver is not satisfied to see 

 only those of his own species obey his warning ; he 

 would have every feathered creature within hearing 

 escape from danger. The curlew is an example and 

 has been observed by wild-fowlers swooping violently 

 upon and trying to drive up a duck that had remained 

 on the ground after all the other birds in the place 

 had taken flight. 



Much more could be said on the subject if there 

 were not so many others to be dealt with in this 

 book : probably every wild-fowler, and in fact every 

 close observer of the actions of birds who reads this 

 chapter will be able to recall some incident he has 

 witnessed which illustrates this helpful spirit. But I 

 cannot conclude before giving one remarkable example 

 of a bird or of birds making themselves masters of a 

 flock not with any important purpose as in the fore- 

 going instances, but purely in play, or for fun. I 



