Environment: The Owl Caper

Death on the sawdust trail

For curators at London's Regent's Park zoo, the deaths were troubling. Between March 1974 and September 1976, 55 owls in the zoo's celebrated collection died. For a while, zookeepers thought that the birds, which usually live to ages of 15 years or more, were simply succumbing to old age. But when younger birds began dying too, sometimes after repeated convulsions, the zoo's chief veterinarian, David Jones, decided it was time for some serious sleuthing.

After performing post-mortems on the carcasses (which had carefully been preserved for further study), Jones...