Effect of nest-box size on nest-site preference and reproduction in American kestrels

  • Published source details Bortolotti G.R. (1994) Effect of nest-box size on nest-site preference and reproduction in American kestrels. Journal of Raptor Research, 28, 127-133.


This study is summarised as evidence for the following.

Action Category

Provide artificial nesting sites for falcons

Action Link
Bird Conservation
  1. Provide artificial nesting sites for falcons

    A replicated study in 1988-93 in boreal forests in Saskatchewan, Canada (Bartolotti 1994), found that American kestrels Falco sparverius nested preferentially in large nest boxes over small (81-94% of 66 kestrels in nest boxes nesting in large boxes when given the choice). Nest boxes were also preferred over natural cavities (a maximum of 5-15% of natural cavities used vs. 53-88% of 17-19 nest boxes used each year). There were no differences in reproductive success or predation rates between large and small nest boxes (40-87% success for 54 clutches in large nest boxes vs. 33-86% success for 23 clutches in small nest boxes). Comparisons with natural cavities were not possible due to small sample sizes. The author argues that providing 345 nest boxes over the study period did not increase the local population. Nest boxes had a basal area of 241 cm2 (small boxes) or 469 cm2 (large boxes) and a 7.5 cm diameter entrance hole.


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