324 BIRD WATCHING 



the same hole and cling there without quarrelling ; but 

 once I saw a bird in a hole attacked by another, who 

 flew suddenly down upon it with a little twittering 

 scream. 



Though each pair of birds excavate their own 

 tunnel, yet the whole community, or, at any rate, a 

 large proportion of it, will sometimes work together, 

 sweeping on to the pit's face in a body, clinging there 

 and burrowing, with a constant twittering, then darting 

 off silently in a cloud and sailing and circling round 

 in the pit's amphitheatre, making, when the sky is 

 blue and the sun bright, a warm and delicious picture 

 such as the Greeks must have loved to gaze on. 



As each bird, however, only works at his own and 

 his partner's hole, it is evident that this kind of social 

 working is not the same as that of ants or bees and 

 other such insect communities, though it has some- 

 thing of that appearance. Sometimes, for a short 

 time, all the birds will keep fluttering round in small 

 circles that only extend a little beyond the face of 

 the cliff", not rising to a greater height than their 

 own tunnels in it, which they almost touch each time, 

 as they come round. They look like eddies in a 

 stream beneath the bank, but are not so silent, for 

 all are twittering excitedly. This is an interesting 

 thing to see, a kind of aerial manoeuvres the special 

 cause of which, if there be one, is not obvious. 



But we will suppose that the birds are now all work- 

 ing, either inside their tunnels or clinging to the face 

 of the cliff". All at once, either at or about the same 

 instant of time, they all fly off", darting away, and 

 disseminate themselves in the sky, not one being 

 left either in or about the pit. In a few minutes 



