Providing evidence to improve practice

Individual study: A comparison of the breeding ecology of four cavity-nesting birds nesting in boxes and tree cavities at the San Joaquin Experimental Range, California, USA

Published source details

Purcell K., Verner J. & Oring L. (1997) A comparison of the breeding ecology of birds nesting in boxes and tree cavities. The Auk, 114, 646-656


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Provide artificial nesting sites for songbirds Bird Conservation

A replicated, controlled study in 1989-94 in grazed and ungrazed pine-oak woodlands in California, USA (Purcell et a. 1997), found that the benefits of nesting in nest boxes, compared to natural cavities, varied between songbird species. Western bluebirds Sialia mexicana gained the most advantage, with higher nesting success, lower predation rates and marginally more young fledged in boxes. Plain titmice Parus inornatus and house wrens Troglodytes aedon marginally benefited from nesting in boxes, with marginally lower predation rates, more eggs hatched and more young fledged (titmice); or lower predation rates, larger clutches, more eggs hatched, more young fledged and marginally higher nesting success (wrens). Ash-throated flycatchers Myiarchus cinerascens experienced no apparent benefits from nesting in boxes. Nest boxes had a basal area of 137 cm2 with 3.2 or 3.8 cm entrance holes, and placed 2 m above ground on trees. Between 44 (1989-91) and 92 (1992-4) boxes were monitored annually.