SWALLOWS.
[TO TEM EDITOR OF THE "SPECTATOR."]
Stu,—Probably many constant readers of the Spectator who are Interested in bird life would welcome an authoritative state- ment in your columns of the cause or causes of the marked and apparently progressive diminution in numbers of the swallow tribe in this country which has been noticeable for many successive summers. Several suggestive letters on the subject which you have recently published have not, I think, elucidated the problem in a way to satisfy the tests of accuracy and com- pleteness. As an observer for over thirty years, I offer the result of my personal experience for what it may be worth, my remarks relating to those species popularly known as swallows, house martins, sand martins, and swifts, although the last belong to a different order—premising that the field of observa- tion has been mainly the eastern side of Scotland.
(1) Swallows have been gradually becoming fewer, and have also been arriving later, for the last ten years at least. (2) House martins have decreased in number to a marked extent in the course of the last twenty to twenty-five years. In some cases of single buildings where eight to twelve nests were in yearly occupation by these birds, either no nests are now to be seen or the few remaining ones are occupied by sparrows to the total exclusion of their rightful owners. The house martins have also been arriving later during the last ten to fifteen years than was their wont previously. (3) Sand martins have also decreased in numbers during the last ten to fifteen years, but to what extent and in what proportion as compared with swallows and house martins I am not prepared to state. (4) Swifts have also decreased in numbers in some places, but, speaking generally, I think not so markedly as either swallows or house martins.
The following reasons have been given by your correspondents and elsewhere in the Press as probably accounting in greater or less degree for the diminished numbers of these birds during the nesting season in recent years in this country; (1) Wintry weather in Europe at the time of the spring migration. (2) Systematic and wholesale destruction of the birds in Italy and the South of France (mainly, it is said, in France) by passing electric current along overhead wires when large numbers are resting upon them in the course of the migratory flights. (3) The Increasing numbers of and capture of the nests by the house sparrow.
Taking these alleged causes in inverse order—as to (3), I think there is general agreement that house sparrows are increasing in number in many parts of the country, and that they have developed a habit of seizing the nests of the house martin as soon as these are in a sufficiently advanced state of construction to suit their purpose, in which they rear their own broods, to the total and permanent exclusion of their rightful owners. But I believe close observers will also agree that the sparrow can be held responsible for this heinous offence in the case of the house martin only, the usual situations of swallows' nests, and perhaps also their comparatively shallow formation, being such that they seem to have no attraction for the sparrow, and it may be taken as certain, I think, that neither sand martins nor swifts are ever molested in this way by sparrows. With regard to (2), it would seem that information of a more definite, detailed, and properly authenticated nature is required—e.g., is it a well authenticated fact that very large numbers of swallows and martins are systematically destroyed annually on the Continent of Europe in the way described? If so, how are the birds disposed of? If for food, where do they find a market, in what quantities and at what prices are they bought both wholesale -and retail. and from what class of consumers
does the demand come? If for ornament, where is the wholesale market, and in what form do skins and feathers reach the retail buyer? I would add that this alleged explanation can scarcely apply to the swift, who, I believe it is correct to state, never alights on overhead wires. And, finally, with respect to (1), is it a well authenticated fact that large numbers of swallows, martins, and swifts have perished on reaching Europe during the spring migration in this and successive preceding years owing to the cause stated?—I am, Sir, &c.,
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