Snowy Plover (Charadrius alexandrinus) nests (n = 415) were monitored to completion on an expansive alkaline flat in north-central Oklahoma in 1995–1996. We reported Mayfield Method nesting success but relied on apparent nesting success to compare differences in successful (hatched) and lost (depredated/flooded) nests in five 1000-ha areas, by microhabitat type, and inside versus outside electric-fence predator exclosures. Apparent nesting success differed by area in 1996 and over both years. Predation differed by area only in 1995, and flooding did not differ by area. Apparent nesting success and predation differed by microhabitat type in 1995 and over both years. Differences were observed among depredated and flooded nests inside versus outside electric-fence predator exclosures. Canids and gulls were primary predators. Nests associated with habitat improvements (1995) and near driftwood debris (1996) encountered higher predation, and nests near driftwood debris were more susceptible to flooding both years. We identified an area on the alkaline flat with the highest nesting success and lowest predation where future conservation efforts for Charadriiformes could be implemented.