The martins, which feed exclusively on insects, if left in possession of their nests, would, unlike many other birds, increase with the population of the country and number of houses. Besides the persecution by sparrows, there is no condition unfavourable to the martins except that when, with their natural confidence in man, too often misplaced, they make their nests close to windows or doors for protection, people commonly destroy them; thus completing the exterminating work of the sparrows. I have heard it said 'they must come there for mischief; they might build anywhere else.' Few seem to notice that, unless where sparrows dare not come, the martins cannot keep a nest. The only thing which saves these birds from total extermination in this country seems to be this—they sometimes manage to rear a late brood after the 'fell adversary to house-martins' (as White of Selborne rightly called the sparrow) has left off nesting and betaken himself to the wheat-fields. But in this way the martins are kept here too long, and sometimes, before their young can fly, are caught by sharp frost in October, and die. The last numerous colony that I knew of, within a few miles of my house, was thus cleared out a few years ago, while my martins, protected from sparrows, and always getting their young off in good time, took no harm.
About my premises the martins, formerly numerous, as elsewhere became fewer and fewer until in 1869 they had nearly disappeared, young ones flying, I think, from only two nests—one close to a window, the other to a door. Towards the end of May, 1870, several nests freshly built under the eaves of the pigeon-house, their favourite place, were all found to be in the possession of sparrows. The indignation with which I had seen this persecution
