The Gapeworm (Syngamus) in Wild Birds

Abstract

DURING 1934 an investigation was carried out, in co-operation with the Oxford University Bureau of Animal Population, into the occurrence of gapeworms (Syngamus) in wild birds. Gapeworms have been recorded from a number of wild birds, and Cram (1) gives a list of 28 species from which gapeworms identical in structure with Syngamus trachea (Montagu)-the gapeworm causing epidemics amongst poultry-have been obtained. In addition to those species included by Cram, gapeworms have also been reported from the sparrow, linnet, martin, kestrel and pigeon. A different species, Syngamus merulae Baylis, occurs in the blackbird (Turdus merula). The presence of gapeworms in wild birds is of practical importance, as Elton and Buckland (2) have pointed out in regard to the rook (Corvus frugilegus), on account of the possibility that birds may spread the parasite amongst poultry, and also for the part the parasite may play in checking the numbers of wild birds. But the part that wild birds play in spreading gapes amongst poultry and game is still undecided. A number of workers have shown that it is possible to infect chickens experimentally with gapeworms obtained from the rook, starling, pheasant, etc., and Clapham (3) has transferred Syngamus merulae from the blackbird to chickens. Taylor (4), however, working with Syngamus from starlings, obtained results which showed that, although the worms occurring in the starling and chicken are morphologically identical, physiological strains evidently exist, and that for this reason it is probable that wild birds do not play so important a role in spreading gapes as was at first expected. Taylor (5) discusses other factors which may tend to retard this spread of the parasite by wild birds. I have to thank the Oxford University Bureau of Animal Population for assistance during this inquiry. The systematic work has been carried out at the British Museum (Natural History) by Dr H. A. Baylis, to whom I am also indebted for much help and advice. I also wish to thank all those who have helped in various ways, and especially the Earl of Eldon; Mr A. D. Middleton; Mr E. L. Taylor, who kindly carried out feeding experiments; and Captain H. B. Moser of the Imperial Chemical Industries Game Research Estate at Knebworth.