18 FEBRUARY 1949, Page 20

Central - heated Roosts

A quaint but most plausible reason, founded, on direct observation, is given for the preference of London sparrows for particular trees as nightly roosts. They like, it seems, their bedrooms to have the advantage of central heating, and therefore select those trees, for example, the Charing Cross planes, which are warmed by the hot air released from the Under- ground. Their knowledge of London is as extensive and peculiar as a Sam Weller's. What a number of them know that ingenious caterer in St. James's Park. His technique is to fill his fist with bread that appears progressively from the hollow at the little finger end of his grip. They thus find a perch and cannot wolf too large a piece. Incidentally, there is evidence that sparrows definitely like noise, for one particular example, that of a roller on rough gravel.