Ancient birds of prey lived off menu of medieval waste

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

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

The research, published today (Thursday, 16 January 2025) in the Journal of Archaeological Science,  examined chemical signatures in bird bones up to 4,000 years old to reveal their diets.

Juliette Waterman, lead researcher at the University of Reading, said: “Historical records show medieval red kites stole food from markets and snatched morsels from people's hands. Some kites showed evidence of eating entirely human-sourced food - a diet very different from modern birds, which mainly hunt rabbits and small mammals.”

No rabbits, just titbits

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. 

The birds' adaptability is particularly evident in medieval towns. Red kites from Oxford, Winchester and other urban sites showed the strongest evidence of feeding on human waste, with chemical signatures indicating they ate more processed foods than their rural counterparts. Today's red kites in urban areas like Reading display similar adaptable feeding habits to their medieval ancestors by taking advantage of food waste and scraps left in gardens.

This study could prove valuable for managing growing raptor populations in modern urban areas while maintaining positive public attitudes towards the protected species.

Image: A red kite depicted in the Aberdeen Bestiary, written and illuminated in England around 1200. Find out more. Credit University of Aberdeen Special Collections.

Juliette Waterman, Stuart Black, Naomi Sykes, William F. Mills, Sean Doherty, Hannah Britton, Riley Smallman, Alison Sheridan, Andrew C. Kitchener, Mark D.E. Fellowes, Tracking 4000 years of raptor diets through isotope analysis reveals urban scavenging with implications for conservation, Journal of Archaeological Science, Volume 175, 2025, 106147, ISSN 0305-4403, https://doi.org/10.1016/j.jas.2024.106147.