( xxxviii ) 



grade butterflies, though individuals may drop in response to 

 an actual attack. This, with their relative ease of capture, is 

 probably the reason why attacks on Danaines, as on the 

 locusts, are relatively often witnessed — even by birds that 

 have to be hungry before they will attack them. Where, 

 however, a bird that is specialised to prey on them is seen in 

 the midst of insects that thus tend to keep on the wing, we 

 may well expect the striking and interesting but potentially 

 misleading observation of wholesale attack on nauseous 

 models that Mr. Fryer has actually recorded. 



Where, in such cases as I have referred to, I myself replaced 

 the pleasanter forms that had gone to ground by releasing 

 appropriate substitutes — usually here, be it noted, unmaimed 

 and thoroughly active and strong- flying individuals — I usually 

 at once secured instances of attack. In one case some of the 

 birds even came and hovered a few feet over my head, like 

 gulls in the wake of a ship, in eager competition for the next 

 butterfly that should go up. 



I witnessed in all during those five years well over eight 

 hundred attacks by wild birds on butterflies — four hundred of 

 them, it is true, by a shrike, the preferences of which I made 

 a point of ascertaining in detail. The immense majority of 

 these attacks were seen within a single month, during which I 

 experimented on the wild birds of the forest outskirts for an 

 hour or two each day, and the attackers included our four com- 

 monest bush-shrikes, our three commonest grass- warblers, our 

 commonest bush- warbler, three out of our four most abundant 

 bulbuls (one of them the commonest insectivorous bird in 

 the country, another by far the commonest bird in the forest), 

 our three commonest Saxicolidae, including both our common 

 robins, and our five commonest flycatchers. Other attacks 

 were by Ploceidae, a pipit, sun-birds, a butcher-bird, drongos 

 of our two common species, a cuckoo-shrike, swallows, a 

 night-jar, bee-eaters, a roller, a common hornbill, also uncon- 

 fined but tame ground-hornbills, two genera of insectivorous 

 kingfishers and a ground-cuckoo. Naturally there were 

 refusals as well, and these with the rejections gave me some 

 clear idea of the birds' preferences ; but I saw numerous cases 

 of eagerness as striking as the one I have quoted above, and 



