Dirty habits: potential for spread of antibiotic-resistance by black-headed gulls from waste-water treatment plants.

Anthropogenic environments such as wastewater treatment plants (WWTPs) and landfills are sources of antimicrobial resistance (AMR). Black-headed gulls (Chroicocephalus ridibundus) frequently use WWTPs and may be vectors for AMR. We used GPS tracking data for 39 gulls for up to 8 months, combined with a shedding curve, to study sources and dispersal distances of AMR in Iberia.

Seed Size, Not Dispersal Syndrome, Determines Potential for Spread of Ricefield Weeds by Gulls.

Recent field data suggest that migratory gulls disperse many rice field weeds by gut passage (endozoochory), most of which are dry fruited and widely assumed to have no long-distance dispersal mechanisms, except via human activity. We investigated this mechanism with a feeding experiment, in which seeds of five common rice field weeds (in order of increasing seed size: , , , , and the fleshy-fruited ) were fed to seven individuals of lesser black-backed gulls held in captivity. We quantified seed survival after collecting faeces at intervals for 33 h after ingestion, then extracting intact seeds and running germination tests, which were also conducted for control seeds.