258 BIRD LIFE GLIMPSES 



robin, wagtail, &c., brings worms or flies to its 

 young. When one thinks of the bird's building 

 habits and its swollen throat, bulged out with mud — 

 as I think it must be — one may surmise that it finds 

 it equally natural to hold a mash of insects in this 

 way. I believe that all the swallow tribe, as well as 

 nightjars, engulf their food in the way that a 

 whale does infusoria, instead of seizing it, first, with 

 the bill — at least that this is their more habitual 

 practice. Thus, I was watching some swallows, once, 

 flying close over the ground, when a large white 

 butterfly (the common cabbage one, I think) sud- 

 denly disappeared, entombed, as it were, in one of 

 them. Now, had a sparrow seized the butterfly the 

 eff^ect would have been quite difl^erent, and so would 

 the process have been. It would have seized it, in 

 fact, but the swallow must have opened its gape, 

 and, in spite of the size of the butterfly, it went down 

 so quickly that, to the eye, it looked as if it had been 

 at once enclosed. Possibly, on account of its size, it 

 was, perforce, held just for a moment, till another 

 gulp helped it down. But the process, as I say, was 

 very diff^erent to the more usual one, and I doubt if 

 an ordinary passerine bird could have swallowed a 

 butterfly on the wing, at all. It is rare, I think, for 

 anything so large as this to be hawked at by swallows 

 or martins. Small insects are their habitual food, 

 and of these the air is often full. That numbers 

 should be swallowed down which are too small to 

 hold in the bill, seems almost a necessity, and that 

 the house-martin, in particular, does this, and brings 

 them up again for the young, in the form of a mash 

 or pulp, I think likely from what I have seen. 



