POLYGLOT ANIMALS 219 



hen-roosts that they might well have forgotten its 

 use and meaning, but they have not. The owner of 

 a model farm, who had noticed the use of this call 

 when a boy in a county where these visits from 

 hawks were not uncommon, and who was a good 

 mimic of bird sounds, tried the effect of uttering it 

 when some fifty or sixty fowls were feeding in a 

 meadow connected with their hen-house by a tunnel 

 running under a fence. At the first call they all 

 looked up, and at the second, though they saw no 

 hawk, they ran to the tunnel and crowded through 

 it into the hen-house. Most of the combined move- 

 ments of the grey partridge, when no enemy is near, 

 are agreed on by means of conversation. They " call " 

 to each other when disposed to take a flight, and have 

 a separate note to indicate that they have taken wing, 

 a word well understood by any of the covey which 

 have not joined the rest, and by other coveys near. 

 When the brood is settling down to sleep the old 

 birds " cluck " to gather the brood, even when they 

 are full-grown. 



In the sustained flight of birds in flocks the use of 

 the voice is discarded, and " flight evolutions " are 

 made by signal. This is analogous to the use of 

 signals to govern the movements of ships in fleets. 

 It is not only more convenient, but more effective 

 than a vocal order. The signal is given by the leading 

 bird, and by the nature of the case is limited to 

 change of direction. Many of the instantaneous 

 changes in the flight of birds in flocks are probably due 

 to the effect of changes in the direction of the wind, 



