Birds are under selective pressure to orient their nests in a direction that reduces the impact of climatic extremes and the risk of the nest being detected by predators. Woodpeckers (Picidae), despite raising young in tree cavities that are safer from predators, should orient the entrances of their nest cavities in a direction that results in a favorable cavity microclimate. Because Picid nest cavity orientation is not well-studied in the Pacific Northwest of North America, we measured nest cavity orientation of White-headed Dryobates albolarvatus, Hairy D. villosus, and Black-backed Picoides arcticus Woodpeckers, Northern Flicker Colaptes auratus, and Williamson's Sapsucker Sphyrapicus thyroideus within burned and unburned, dry conifer forests of the eastern Cascade Range in Washington, USA (N = 684). Each woodpecker species had a mean angle of nest cavity orientation in a northerly or easterly direction and ranged from 12.3° for the Northern Flicker to 117.6° for the Black-backed Woodpecker. Hairy Woodpeckers, Northern Flickers, and White-headed Woodpeckers showed strong evidence for nonrandom nest cavity orientation, and Northern Flickers showed particularly high dispersion with a multimodal distribution of cavity orientations. Although the mean and variance of cavity orientations did not differ substantially between woodpeckers, cavity orientation differed based on nest tree species. Woodpeckers may orient their nest cavities in an easterly direction so that cavities warm quicker in the morning, to avoid hot afternoon temperatures and prevailing west and north westerly winds, and because the majority of cavities were located in burned forest where shading from canopy cover is reduced.
How to translate text using browser tools
29 May 2024
Woodpecker Nest Cavity Orientation in Dry Conifer Forests of the Pacific Northwest, USA
Jeffrey M. Kozma,
Teresa J. Lorenz,
Andrew N. Stillman
ACCESS THE FULL ARTICLE
![](/ContentImages/journals/aorn/58/2/2/WebImages/068.058.0200.Cover.jpg)
Acta Ornithologica
Vol. 58 • No. 2
Winter 2023
Vol. 58 • No. 2
Winter 2023
Douglas-fir
Dryobates
nest orientation
Picoides
ponderosa pine
snags
Sphyrapicus