Energetics of the Straling (Sturnus Vulgaris) In a Pine Woods

Field and laboratory studies were conducted during the winter of 1975—76 to assess and quantify the energetic determinants of the communal roosting behavior of the Starling (Sturnus vulgaris) in a pine woods. Of the microclimate factors measured, only the wind velocity varied significantly between the recordings obtained outside of the pine woods and in areas within the woods that were used extensively as roost sites. Subjection to wind velocities of 2.9, 7.3, and 15.1 km/h at ambient temperatures of —10.0°, 0.0°, and 5.0°C caused significant increases in metabolism of the 30 Starlings tested. Selection of microclimates where wind velocity is virtually eliminated confers upon roost inhabitants the energetic advantage derived from minimized forced convective heat loss. The reduction in daily existence metabolism is estimated to range from 12% to 38% under environmental conditions that are normally presented in temperate latitudes during winter nights.