2025/01/01 by Justin Chambrelin, Julien Gernigon, J.C. Lemesle +2 · 1 voice
Environmental Science · Earth and Planetary Sciences · #Marine and fisheries research #Coral and Marine Ecosystems Studies #Marine and coastal plant biology
paper · doi:10.61350/sbj.37.4
Egg removal campaigns are a common practice in France and Europe, including in natural areas, to manage conflicts between large gulls and other species or humans. Few studies have evaluated the impact of this practice on the breeding site fidelity of targeted colonies. The Lilleau des Niges Nature Reserve hosts a mixed-species colony of gulls (Laridae), including European Herring Gull Larus argentatus, Lesser Black-backed Gull L. fuscus, and Great Black-backed Gull L. marinus. The gull colony was controlled between 1990 and 2017 using egg removal. A citizen-science led capture-recapture study began in 2010, and resighting of colour-marked individuals were obtained at the breeding colony between 2010 and 2022. By using a multi-event model, we assessed the colony fidelity and adult survival during the egg removal campaign (2010–17) and in the following years (2018–22). Breeding site fidelity was lower during the years of egg removal than in subsequent years for two species (a decrease of 0.07 for Herring Gull and 0.22 for Lesser Black-backed Gull). The probability of survival for all species declined during the study period but could not be directly linked to gull control measures. No difference between sexes was found for these two parameters. Moreover, colour ring resighting by citizen scientists showed that some individuals moved from natural colonies to urban colonies. These initial results suggest that the local population dynamics of gulls have changed over time, although a causal link to egg removal campaigns cannot be confirmed.