16 MAY 1925, Page 18

THE OAK-TREE PEST

[To the Editor of the SPECTATOR.] SIR,---It does not appear to be generally known that young rooks readily devour the oak-leaf moth caterpillars (Tortrix Viridana) which kill oak trees in thousands. Trees attacked by it become liable to oak mildew (Oidium). Whenever there is a plague of these devastators, the parent birds bring their youngsters to the banquet. Most field naturalists and owners of oak woods know this interesting fact, yet the destruction of the little green Tortrix moth by rooks is unknown to Dr. Walter E. Collinge, a noted ornithological analyst, as may be seen from. his statement in Country Life, March 7th, p. 365.

How, then, are rooks to have a fair hearing on their credit and debit account in the House of Commons ? There is urgent need of a wider range of knowledge .than that provided by limited laboratory investigations of food content. If some well-known field-naturalists would work conjointly with ornithological analysts, the faults of these much-maligned birds would be inconspicuous when balanced against their