Individual study: Ferruginous hawk Buteo regalis, but not Swainson’s hawk B. swainsoni populations increase in Canadian pastures, following the provision of nesting platforms
Schmutz J.K., Fyfe R.W., Moore D.A. & Smith A.R. (1984) Artificial nests for ferruginous and Swainson's hawks. The Journal of Wildlife Management, 48, 1009-1013
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Provide artificial nesting sites for raptors
A controlled before-and-after study over nine years in two pastoral sites in Canada (Schmutz et al. 1984) found that the breeding density of ferruginous hawks Buteo regalis increased following the provision of 98 nesting platforms in 1975 in an experimental area (nine nests in 1975 vs. 14 in 1983, increased populations in all five subareas). There was no increase in a control area, without platforms. Swainson’s hawk B. swainsoni populations also increased from 0.1 pairs/km2 in 1975 to 0.15 pairs/km2 in 1983, but there were no differences between experimental and control areas. Less than 40% of hawk populations used platforms for the first two years, but use increased with time. Platforms were either 120 x 60 x 20 cm wooden boxes, or wire baskets, 60-90 cm in diameter and 20 cm deep. Both were lined with shrubs or grasses and mounted on wooden poles, buried 60-90 cm in the ground. After 17 ploes fell, the authors recommended burying them deeper. Platforms provided with shade were used more than un-shaded ones.