No detrimental effects of wing-harnessed GPS devices on the breeding performance of Yellow-legged Gulls (Larus michahellis): A multy-colony evaluation

A recent study revealed that wing-harnessed tracking devices negatively affected reproductive success of Great Black-backed Gulls Larus marinus. To evaluate the generality of this effect in large gulls, we investigated the reproductive performance associated with the same type of GPS-mounted system in four Mediterranean breeding colonies of the Yellow-legged Gull Larus michahellis in 2022. We found no significant difference in reproductive parameters among adults handled with a mounted device, adults handled with no device, and controls, and no interaction with colony of origin. The impact of the GPS harness system on short-term reproduction is therefore not generalizable among larid species, and should be tested and reported whenever a new tracking programme is employed.