It first becomes widely noticeable as a habit about May 25th, and continues every fine quiet night till about July 20th. After that date, although it does not altogether cease, it appears to be indulged in merely to an individual and rather desultory extent. In the bright gloaming of our northern summer, about the time the last Blackbird lays aside his flute for the night, the Gulls put in a rather sudden appearance, flitting low along the grass, hedgerows, and clumps of shrubs, confining their attentions to such places at first. As the evening wears on they rise higher over the tree-tops and along the woodlands, and for the remainder of the night they frequent these loftier heights, only coming down lower when the night is specially bright, or becomes breezy. So far as I have seen, they take any and every moth they can catch. Early in the evening they can be seen snapping up many easily recognizable species. I have seen them take moths so small as a Depressaria. The Gulls capture the moths most dexterously, and it is curious to notice a Gull occasionally make a rush and chase a Bat, probably getting jealous of its moth-catching rival, or perhaps mistaking the flying insectivore for an insect of more than usual dimensions. Standing beneath a tree, over whose top a Gull is gliding, one hears the chuckle of satisfaction emitted when it catches and swallows a victim. Many of the swift-flying Noctuæ are safe from the Gulls' attentions so long as their usual headlong flight of the early evening continues, but when speed slackens, and they begin to dawdle—as perhaps all the species do in later hours—then the Gulls snap them up continuously.
This moth-catching habit, which has developed so regularly in recent years, occupies, as I have stated, a well-defined period, beginning quite abruptly, and almost to an hour at the same time each season. In various ways, which need not be particularized, I have ascertained with tolerable certainty that throughout the region specified the moths thus caught are for the purpose of feeding the young. No doubt, immature non-breeding birds take part in the pursuit, and apply the proceeds to their own uses, but the main purpose is capture by the breeding birds to feed their young ones.
In this connection I may refer to an excellent paper by Prof. J. Arthur Thomson, M.A., entitled "Some Notes on the Behaviour of Young Gulls artificially hatched and naturally hatched," read
