Florida Grasshopper Sparrow (Ammodramus savannarum floridanus) nests are oriented northeast

Abstract

Nest microclimate can be affected by wind and solar radiation, which can influence offspring survival. The endangered Florida Grasshopper Sparrow (Ammodramus savannarum floridanus) constructs a domed nest on the ground in dry prairie and pasture habitats of central Florida. We measured the nest opening orientation for 116 Florida Grasshopper Sparrow nests across 2 sites with different habitats (2014–2016). Nest openings were primarily oriented to the northeast and orientation did not differ by site. Nest opening orientation did not influence the probability that a nest would successfully fledge at least 1 nestling. It is possible that Florida Grasshopper Sparrows may orient nests to the northeast to avoid wind-blown rain from summer storms and solar radiation during the hottest part of the day, but high local rates of nest predation documented at both sites mask the selective advantage of nest orientation on nest survival.