Movement networks of breeding gulls reveal differential capacity for habitat connectivity across populations

Gulls (Larus spp.) are ubiquitous birds known to forage across a variety of habitat types and, like other coastal birds, can facilitate landscape connectivity through nutrient and pathogen transfer and deposition. During the breeding season, gulls are constrained to forage near their nesting colonies and often revisit the same foraging sites, thus potentially concentrating their ecological impact. Using global positioning system (GPS) loggers (n = 78) deployed in 2019–2022, we investigated the movement networks of breeding American herring gulls and great black-backed gulls (L. smithsonianus and L. marinus) from two study sites on the northeast coast of the United States. Using network analysis, we found that gulls from the urban-adjacent colony showed a greater potential to facilitate landscape connectivity as demonstrated by a greater number of network nodes, more movements between distinct habitats and less random movements than gulls from the urban-distant colony. Individual specialization, dietary flexibility, habitat availability and the spatio-temporal predictability of urban and coastal food resources may have also influenced observed connectivity patterns and locations of potentially high concentrations of ecological impact. Our findings highlight the importance of understanding breeding gull movement structures and the ability of network-based approaches to reveal the potential for coastal birds to facilitate landscape connectivity.