Factors Affecting Parental Behavior in Semipalmated Plovers

We studied Semipalmated Plovers (Charadrius semipalmatus) during two field seasons in Churchill, Manitoba, to examine the contribution of males and females to parental care during incubation and chick rearing, and to test the hypothesis that birds nesting in habitats with higher visibility and more food (i.e. coastal habitats) tend chicks less closely than birds nesting in habitats with lower visibility and less food (i.e. inland habitats). Males at the coast flew and vocalized more than females during the chick-rearing period, and, in both areas, incubated during the darkest hours (2400 to 0220), whereas females incubated from 0220 to 0530. Incubation shifts were longer at night than during the day but did not differ between sexes or habitats. Incubation by males during the darkest hours may allow females to feed when invertebrates are most active, and may be a mechanism by which fe­ males obtain a better energy balance. Coastal habitats contained more food than inland habitats and more potential predators of both chicks and adults. During incubation, parents in coastal habitats exhibited fewer vigilant behaviors than parents in inland habitats, although the overall time budgets for the most common behaviors did not differ between habitats. Parent-chick distances did not differ between coastal and inland habitats, although as chicks became older, they foraged farther from their parents and were brooded less frequently. The apparent response of adults to predators did not differ between the two habitats. The time that parents spent brooding chicks was negatively correlated with ambient temperatures but was not affected by habitat.