September 1954 – vol. 47, issue 9–320 SIRS,--I read with great interest the paper by Desmond Morris (antea, pp. 33-49) and the subsequent letter by A. J. Bruce (antea, p. 215) in which this subject is discussed. Bruce's theory, that a thrush (Turdus sp.) cannot afford to use its feet owing to the ever-present need to be able to take off instantly may well be correct. I think, however, that it is likely to be only a contributoryfactor. ... This article is only available to registered users.To read more, please log in or purchase a subscription.