2 FEBRUARY 1934, Page 17

Vanishing Mice

The ingenious school of young biologists at Oxford continue their enquiries into the cyclical changes in the population of animals, especially the smaller mammals. A good deal of the evidence certainly suggests that several species undergo a regular rise, lasting in several species for just four years, and in the next year collapse to the minimum. Have they, I wonder, any evidence about that engaging little creature, the dormouse ? Someone who kept one as a pet complained that it had "no habits " ; but they are pretty and make the neatest -nest of any hibernating animal. It is even more ingenious than a bird's nest, for there is no exit whatever. The problem of the apple in the dumpling is nothing to it. Several people; including the very best observer in this branch of natural history, Miss Frances Pitt, lament that the dormouse in their neighbourhood is virtually extinct. It is common enough itt Hertfordshire, where also flourish in large quantity the water and field vole, the yellow.neeked mouse and the greater shrew. In my experience there never was-a year in which the popula- tion of long-tailed field mice was anything but enormous. -