Effects of nest success and mate fidelity on breeding dispersal in a population of Snowy Plovers Charadrius nivosus

Breeding dispersal subsequent to nest failure is hypothesised to be a behavioural response to danger posed by nest predators. We used histories and locations of male and female Snowy Plover Charadrius nivosus nests in northern California over a 10-year period to examine effects of nest fate, mate fidelity, residency, predator exclosures, and age on dispersal distance. Within years, females moved a median distance of 2.2 km after changing mates; males moved a median of 0.9 km. Between years, plovers moved the shortest distances when they retained a mate from the prior year and were successful in hatching eggs (males = 0.2 km, females = 0.3 km). Both females (13.0 km) and males (2.6 km) dispersed farther when mate change coincided with nest failure in the prior year. The observation that most plovers did not disperse far enough to move away from sites where predators are abundant and have strong effects on plover reproductive success suggests that effective predator management will be challenging.