PERIODIC VARIATIONS.
The ups and downs of the population of birds are hard to understand. Like some of the mammals they seem to illustrate some untraceable law of periodicity. The redstart is a conspicuous example among the regular immigrants, and time goldfinch (which has suffered most of all from trappers) among our home birds. An Irish correspondent some while ago gave me some very curious examples. At one time the jackdaws completely routed the choughs. To-day the choughs have returned ; and this experience exactly coincides with mine in relation to the same two birds—not in South Ireland but in South Wales. Again the goldfinch has returned to Ireland after a long period of scarcity just as it has returned to England ; and some hold that the " peak years " of the goldfinch correspond roughly with the " valley years" of the greenfinch. My own experience is that whatever happens to other birds the greenfinch and chaffinch are always multi- tudinous. Perhaps the two most certain examples of the steady multiplication in recent years of species once more or less scarce are the greater crested grebe and the greater spotted woodpecker.
IV. BEACH THOMAS.
[Owing to Sir William Beach Thomas's absence abroad, this page will be suspended -from February 14th to March 7th inclusice.—Ed. Spectator.]
Previous page
