Nest-site selection by pied-billed grebes Podilymbus podiceps
At a permanent freshwater marsh near Amherst, Nova Scotia, pied-billed grebes showed no preferences for nesting in association with any emergent plant species. Timing of authors' nest visits was an extremely important factor influencing likelihood of nest failure. Nest sites were characterized by sparser coverage of water by emergent vegetation, deeper water, closer proximity to open water, and greater distance from shore than randomly-chosen marsh locations. Pied-billed grebes also avoided nesting on edges of stands of emergent vegetation that were exposed to wave action, and aggregations of nests were found in areas with stands of emergent vegetation separated by broad channels of open water. Physical features were thus more important than plant species in determining nest placement. -from Authors
Forbes, M, Barkhouse, H.P., & Smith, P.C. (1989). Nest-site selection by pied-billed grebes Podilymbus podiceps. Ornis Scandinavica, 20(3), 211–218.