1956, a female Mallard (Anas platyrhynchos) wearing a British Museum ring (941642) was recaptured in the decoy a t Slimbridge, Gloucestershire. She was accompanied by four ducklings, estimated to be four or five days old. This female was marked at Slimbridge on 4th September 1956, when Mr. Peter Scott, who caught the bird, recorded it as a juvenile female. In deciding its age, he used the presence of some juvenile tail-feathers, with notched tips, as the principal criterion. The age at which young Mallard shed these feathers is subject to some individual variation, but, at least at Slimbridge, they are rarely retained later than about eighteen weeks after hatching. This suggests that 941642 is unlikely to have been hatched before the beginning of May 1956, so that she became a mother at scarcely six months old and musthave begun laying eggs less than five months after being hatched. Several other female Mallard appeared with broods in early November. None of these other females could be caught, so t h a t they offer no additional proof of early maturity, but the possibility that late autumn broods, which occur quite frequently in this species, are produced by early-maturing females rather than by females that had bred or attempted to breed earlier in the year is perhaps worthy of note. Though 941642 and her offspring have evaded capture since 6th November, it should be recorded that all four ducklings survived to fly in early January, although nearly all the other November broods