“The butterflies include a number of minor pests, of which _Melanitis ismene_ was taken by _Merops viridis_ and _Papilio pammon_ by _Acridotheres tristis_. Other well-known pests are _Pieris brassicae_, _Virachola isocrates_ and _Papilio demoleus_. _Belenois mesentina_, a Pierid, was seen to be taken on one occasion by the king-crow, and _Ilerda sena_ by _Passer domesticus_, both of which insects are neutral.
“Moths include many major pests of varied habits—defoliators, miners, cut-worms, grain and fabric pests. The larvae form an inexhaustible supply of insect food to almost all species of insectivorous birds, and even many species of birds that when mature feed almost, if not quite, entirely on grain and seeds are when in the nest fed very largely on caterpillars by the parent birds.”
Obviously, then, in India birds comparatively rarely attack butterflies; but they devour millions of caterpillars. It is the same in other parts of the world.
Mr. G. A. K. Marshall, in the course of five years’ observation in South Africa, recorded eight cases of birds capturing butterflies.
Similarly Mr. Banta points out in various issues of _Nature_, in 1912, that all the evidence available shows that in North America birds very rarely capture butterflies. Field naturalists scarcely ever witness a butterfly chased by a bird. Of 40,000 stomachs of birds examined very few were found to contain remains of butterflies.
In 1911 the butterflies of the species _Eugonia californica_ were so numerous that “the ground was often blackened with them, and great swarms of them filled the air from morning to evening.” Yet of the birds in the locality where those butterflies were most numerous, only five out of forty-five species were found by direct observation and stomach examination to eat the eugonia, and the only bird that fed off them copiously was the brewer blackbird (_Euphagus cyanocephalus_) which is almost omnivorous, and eats insects of all kinds, even if they be what Darwinians call warningly coloured!
Now, modern theorists, as a rule, ignore facts such as these, and this certainly is the wisest course they can pursue, unless they are ready to give up these theories or make themselves look foolish.
