Nest-site choice (nest boxes vs. natural cavities) of five cavity-nesting bird species at Beaver Creek Watershed, Coconino National Forest, Arizona, USA

  • Published source details Brawn J. (1988) Selectivity and ecological consequences of cavity nesters using natural vs. artificial nest sites. The Auk, 105, 789-791


This study investigated nest-sit preference (artificial nest boxes versus natural cavities) of five secondary cavity-nesting bird species (violet-green swallow Tachycineta thalassina, pygmy nuthatch Sitta pygmaea, western bluebird Sialia mexicana, mountain chickadee Parus gambeli and white-breasted nuthatch Sitta carolinensis) in ponderosa pine forest of northern Arizona.

Study area: The study was conducted in three, 8 ha plots (dominated by ponderosa pine Pinus ponderosa with Gambel oak Quercus gambelii) in the Beaver Creek Watershed, Coconino National Forest, Arizona, USA.

Nest boxes: In 1980, before the breeding season, 60 nest boxes were installed in three woodland treatment plots: (1) dense woodland - 637 live trees/ha and 39 dead trees/ha; (2) thinned woodland - 225 live trees/ha and 21 dead trees/ha; and (3) open woodland - 69 live trees/ha and seven dead trees/ha.

Boxes (1,900 cmó) were made of a mixture of concrete and wood chips with one of two entrance hole diameters (38 or 32 mm). Thirty boxes with each entrance size were installed in each plot on trees at 8 m average height. The boxes were spaced evenly throughout the plots.

Nest monitoring: Nest boxes were inspected and active nests in natural cavities searched for in each plot throughout each breeding season (1980-1983). A box was considered occupied if it contained eggs. Natural cavities were deemed occupied after observation of feeding visits or removal of faecal sacs.

Overall, for four of the study species (the swallow, pygmy nuthatch, bluebird and chickadee) more than 85% of nests were located in boxes in the thinned and open plots; potentially suitable natural cavities in these plots were largely ignored after boxes became available, presumably as the birds viewed the boxes as providing higher quality nest sites and the boxes were easily locatable. White-breasted nuthatch use of boxes in these plots was lower (c.63%) compared to the other species.

In contrast, no boxes were used in the densely wooded plot in 1980, and 65-70% of all nests located thereafter were in natural cavities. Within species (except western bluebird), the proportion of nests in boxes in the plot was thus significantly less than in the other two, less densely wooded, plots. Predation of nests in boxes and natural cavities was <5% in all plots, therefore vulnerability of boxes to predation appeared unimportant in the study area. About 70% of the boxes in the dense plot were never occupied; thick vegetation may have prevented their detection.

The author suggests that, as well as providing suitable nest cavities, nest boxes may benefit birds attempting reproduction by reducing time spent searching for potential nest sites.

Note: If using or referring to this published study, please read and quote the original paper, which can be viewed at:

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