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Providing evidence to improve practice

Action: Provide artificial nesting sites for rollers Bird Conservation

Key messages

Read our guidance on Key messages before continuing

  • A before-and-after study from Spain found that the use of nest boxes by European rollers Coracias garrulous increased over time and that use varied between habitats.
  • A replicated controlled trial from Spain found no difference in success rates between new and old nest boxes, although birds in old boxes began nesting earlier.


Supporting evidence from individual studies


A replicated, controlled study in pastureland in 1989-90 in Extramadura, Spain (Avilés et al. 2000), found that European rollers Coracias garrulus nesting in new nest boxes did not have higher reproductive success than those nesting in older nest boxes (average of 4.3 eggs/clutch, 69% breeding success and 4.0 fledglings/successful nest for 16 pairs in old boxes vs. 4.1 eggs/clutch, 83% and 3.6 fledglings/nest for 49 pairs in new boxes) and began laying significantly later (average laying date of 25th May for clutches in 16 old boxes vs. 30th May for 49 new boxes). Rollers did not appear to preferentially use either old or new boxes. Boxes were 32 x 18 x 19 cm with a 6 x 18 cm entrance hole and were installed on power line pylons at an average density of 9.5 boxes/km of power line.



A before-and-after study in agricultural habitats in Extramadura, Spain (Avilés & Parejo 2004), found that the number of European rollers Coracias garrulus using artificial nest boxes increased from 29 in 1988 (76% of the 38 boxes available) to 350 in 1991 (55% of 641 available boxes). Nest boxes use varied with habitat: from 68% use in unwooded pasture (256 boxes available) to only 34% in cereal fields with holm oaks (32 boxes). Nest boxes were the same design as in Avilés et al. 2000.


Referenced papers

Please cite as:

Williams, D.R., Child, M.F., Dicks, L.V., Ockendon, N., Pople, R.G., Showler, D.A., Walsh, J.C., zu Ermgassen, E.K.H.J. & Sutherland, W.J. (2019) Bird Conservation. Pages 141-290 in: W.J. Sutherland, L.V. Dicks, N. Ockendon, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2019. Open Book Publishers, Cambridge, UK.