No abstract

Shorebird populations have declined due to several threats throughout their annual cycle. Anthropogenic disturbance is one of the most ubiquitous threats to shorebird conservation in North America. Here, we studied the influence of human disturbance on shorebird community dynamics during migration and winter in Ensenada de La Paz, a subtropical coastal wetland in Mexico. We used negative binomial generalized linear mixed models to investigate the associations between spatial, biological, and anthropogenic variation and local shorebird abundance that accounted for shorebird body size (small, medium, and large) and foraging strategy (visual and tactile) of 22 shorebird species. After controlling for these different correlates of abundance, human disturbance (people, vehicles, and dogs) was negatively associated with shorebird abundance. During winter, all shorebird species were negatively related to human disturbance but positively associated with presence of raptors. However, small, tactile foraging birds exhibited a proportionally larger negative response to human disturbance than other shorebird types, indicative of guild-level sensitivities to human disturbance regimes. The positive association between shorebird abundance and disturbance from predators was unexpected. Shorebirds likely concentrate in large groups to reduce predation risk, resulting in higher densities of shorebirds occurring in areas with high predation risk. Understanding factors influencing the abundance and habitat use of shorebirds on their non-breeding grounds is paramount to support management and conservation policies for shorebirds and their habitats.