Abstract

Urbanization causes wildlife declines and biodiversity loss, but some species benefit from resources offered by human-altered habitats. Yet, if hosts change their behaviors, aggregate near food sources and interact with novel species, “resource provisioning” can increase contact rates and exposure to pathogens, or alter the host's immune function. This also affects disease risks for humans, especially when feeding brings people into close proximity with wildlife. We examined the recent urbanization of white ibis (Eudocimus albus) in Florida to ask: 1) How do urban resources affect patterns of movement and aggregation? 2) Does resource provisioning affect host stress and immunity? We predicted that human-provided food/water would reduce movement of ibis, and alter susceptibility to infection. Through radio telemetry (n=30) we found that ibis movements are limited to foraging and roosting in urban settings. Ibis (n=261) are infected with Salmonella spp. (13% prevalence), which was negatively correlated with wetland cover. Sixty-two percent (n=16) of PFGE patterns for ibis Salmonella spp. isolates matched profiles in CDC PulseNet USA database. We also found evidence for a surprisingly high prevalence of paramyxovirus and avian influenza antibodies (74% and 89%, respectively; n=98). We found higher levels of fecal and plasma corticosterone metabolites than previously reported for ibis maintained on natural diets. Analysis of bactericidal capacity against E. coli (BKA) showed a high ability to fight off E. coli, compared to other species, but with high individual variation. Results indicate that the behavior, pathogen prevalence and immune function of ibis has changed to adapt to urban environments.