28 MARCH 1931, Page 16

REVERSED BIRD MIGRATION

[To the Editor of the SPECTATOR.]

Sia,--z-In your issue of March 21st, Sir W. Beach Thomas writes : "It has not perhaps happened before within our memory that March weather, however leonine, has routed migrating birds."

Compulsory and wholesale reversals of the great northward spring movement of birds, such as have been reported this month from Germany and Switzerland, must be of rare occur- rence. Gatke, in his great work oft the birds of Heligoland, records that on the night of March 16th, 1879, "hundreds of thousands of migrants, belonging for the most part to the Curlew, the Golden Plover, the Lapwing, and their congeners, passed over Heligoland in one violent rush westwards, making the darkness of the night resound with the wild babel of their calls. Excepting that much greater haste was displayed on the part of the wanderers, the movement exactly resembled a powerful autumn migration. There was a light south-westerly wind, the weather being mild ; it was thawing, and the evening was foggy. Hence, from the local conditions of the weather, no apparent cause could be assigned for a movement of this nature. On the following day, however, the wind changed to east-north-east, and a frost set in which lasted until the 28th of the month. Undoubtedly this same wintry weather had set in, one or two days before, in regions lying far to the east or east-north-east of Heligoland.—I am, Sir, &c.,