Seagulls from a species that feeds on garbage are harbouring drug-resistant superbugs, a study has found.
Researchers analysed 57 samples of droppings from the yellow-legged gull Larus cachinnans. They found that one in 10 carried superbug bacteria resistant to the "last resort" antibiotic vancomycin, which is used when most others have failed.
The white and grey birds are scavenging omnivores and opportunistic marine feeders. They can often be seen flocking on rubbish tips, and are common in many southern parts of the UK. Scientists collected the samples from an island off the Portuguese coast.
Lead researcher Dr Gilberto Igrejas, from the University of Tras-os-Montes and Alto Douro in Portugal, said: "We used a novel technique called proteomics to detect the maximum number of bacterial proteins which are thought to be connected in some, as yet unknown, way to antibiotic resistance.
"Migrating birds that fly and travel long distances can act as transporters, or as reservoirs, of antibiotic-resistant bacteria and may consequently have a significant epidemiological role in the dissemination of resistance."
The research is published in the online journal Proteome Science.