Habitat selection and clutch fate of Piping Plovers (Charadrius melodus) breeding at Lake Diefenbaker, Saskatchewan

Abstract

We studied habitat selection by Piping Plovers (Charadrius melodus) at Lake Diefenbaker, Saskatchewan, during the 1992 and 1993 breeding seasons. Habitat selection was investigated at three levels: beach, territory, and nest site. Nest beaches had significantly more gravel substrate than non-nest beaches (F[1,11] = 21.52, p < 0.01). There was no significant difference in width between nest and non-nest beaches. All Piping Plover nests were located on gravel, though this substrate only accounted for approximately 43% of nest beach area. Nest sites were significantly farther from the nearest water (F[1,181] = 12.24, p < 0.01), the main water body (F[1,181] = 6.55, p < 0.05), and had significantly more stones (F[1,161] = 10.98, p < 0.01) and rocks (Z = 2.93, p < 0.01) than random sites. Distance to the nearest water source, number of stones per square metre, and distance to the vegetation line were the three variables used by the stepwise discriminant function analysis to correctly classify 41.8% of nest sites and 87.1% of random sites. This was still significantly better than chance (Z = 3.66, p < 0.01). The low percentage of correctly classified nest sites may indicate that some plovers at this lake used nest sites on lower quality substrate. Flooded nests were significantly closer to water than successful nests and depredated nests were closer to the vegetation line than successful nests.