Birds of prey in medieval Britain relied far more heavily on scavenging human waste than previously thought, according to research that analyzed more than 30 ancient bird skeletons.

Ancient red kites, buzzards and eagles that lived near towns such as Oxford, Winchester and London were feeding extensively on scraps, rather than hunting live prey.

The study, which involved researchers examining bones from 11 red kites, 18 common buzzards and three white-tailed eagles found at archaeological sites across Britain, revealed the relationship between birds of prey and human settlements stretches back thousands of years.

The absence of rabbits in Britain before medieval times likely pushed birds of prey to find alternative food in human settlements, where waste was abundant. Analysis showed medieval birds had similar chemical signatures in their bones to humans living in the same areas, suggesting they regularly scavenged from rubbish dumps and butchery waste.