AN AERIAL WHALE 33 



often resolved themselves into chasing and sporting 

 with one another. That they occasionally caught 

 moths or cockchafers seems, in itself, likely, but I 

 never had reason to suppose that these were their 

 particular quarry. It seems strange that I should 

 have so rarely seen them catch any large insect I 

 cannot, indeed, remember an instance ; but, on the 

 other hand, they might well have engulfed crowds 

 of small ones, as they flew, without my being 

 able to detect it, and without any special effort 

 to do so. That the air is often full of these 

 gnats, little flies, &c. may be conjectured by 

 watching swallows, and also bats. Indeed, one 

 may both see and feel them oneself in cycling, 

 for instance, when I have often had a small beetle, 

 constructed on the general plan of a devil's coach- 

 horse, sticking all over me. For all the above 

 reasons, my view is that it is the smaller things of 

 the air which form the staple of the nightjar's food, 

 and that its huge gape, and, possibly, the bristles on 

 either side of the upper jaw, stand in relation to the 

 enormous numbers of these which it engulfs. The 

 bird, in fact and this would apply equally to the 

 other members of the family plays, in my idea, 

 the part of an aerial whale. 



I have watched a pair of nightjars through the 

 whole process of hatching out their eggs and bring- 

 ing up their young, as long as the latter were to be 

 found ; for they got away from the nest if the bare 

 ground may be called one long before they could 

 fly. It was on the last day of June that the chicks 

 first burst upon me. I had been watching the sitting 

 bird for some time, and had noticed that the 



