HABITAT SELECTION AND CLUTCH FATE OF PIPING-PLOVERS (CHARADRIUS-MELODUS) BREEDING AT LAKE DIEFENBAKER, SASKATCHEWAN

We studied habitat selection by Piping Plovers (Charadrius melodus) at Lake Diefenbaker, Saskatchewan, during the 1992 and 1993 breeding sea sons. Habitat selection was investigated at three levels: beach, terri tory, and nest site. Nest beaches had significantly more gravel substr ate than non-nest beaches (F-[1,F-11] = 21.52, p < 0.01). There was no significant difference in width between nest and non-nest beaches. Al l Piping Plover nests were located on gravel, though this substrate on ly accounted for approximately 43% of nest beach area. Nest sites were significantly farther from the nearest water (F-[1,F-181] = 12.24, p < 0.01), the main water body (F-[1,F-181] = 6.55, p < 0.05), and had s ignificantly more stones (F-[1,F-161] = 10.98, p < 0.01) and rocks (Z = 2.93, p < 0.01) than random sites. Distance to the nearest water sou rce, number of stones per square metre, and distance to the vegetation line were the three variables used by the stepwise discriminant funct ion analysis to correctly classify 41.8% of nest sites and 87.1% of ra ndom 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 quali ty substrate. Flooded nests were significantly closer to water than su ccessful nests and depredated nests were closer to the vegetation line than successful nests.