Document Type

Article

Publication Date

7-17-2009

Abstract

Orientation of the entrances of bird nests may be especially important in grasslands, where protective cover from solar radiation and wind is minimal. We examined orientation patterns of nest-dome entrances in two grassland bird species, the Grasshopper Sparrow (Ammodramus savannarum) and the Eastern Meadowlark (Sturnella magna). We noted how these patterns changed over the nesting season and how they related to prevailing wind direction. We found that Grasshopper Sparrow (n = 333) and Eastern Meadowlark (n = 272) nests were oriented nonrandomly, toward the northeast (ā = 33.4° and 52.9°, respectively). Prevailing wind in the study region was approximately from the south (ā = 171.1°); therefore, nests of the two species were generally oriented downwind. Nest orientation of the Eastern Meadowlark shifted northward as the nesting season progressed, coinciding with a southeastward shift in prevailing wind direction. Conversely, in one year we observed a seasonal shift toward the east in nest orientation of the Grasshopper Sparrow. Nest orientation in these species may represent a trade-off between various factors, including wind and solar radiation. © 2009 by The Cooper Ornithological Society. All rights reserved.

Publication Source (Journal or Book title)

Condor

First Page

395

Last Page

399

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