The BTO barn owl monitoring programme: Final report 2000-2009

  • Published source details Dadam D., Barimore C.J., Shawyer C.R. & Leech D.I. (2011) The BTO barn owl monitoring programme: Final report 2000-2009 . British Trust for Ornithology report, BTO Research Report 577.


This study is summarised as evidence for the following.

Action Category

Provide owl nest boxes (Tawny owl, Barn owl)

Action Link
Farmland Conservation
  1. Provide owl nest boxes (Tawny owl, Barn owl)

    A replicated study of almost 800 barn owl Tyto alba nest sites (mainly boxes) over ten years across the UK (Dadam et al. 2011) found that owls were present at 70% of the 5466 sites visited and bred at 54%. Occupancy and the proportion breeding decreased from 2001 to 2009, but were not affected by the number of boxes at each site. Occupancy was greater in rough grassland than arable land, and was lowest in pastoral areas. However the proportion breeding did not differ with habitat. Brood size was larger in rough grassland than arable sites. Female weight at laying did not differ over time, whereas average laying date tended to be earlier and clutch and brood size tended to increase over the study, but not significantly. Occupancy rates were highest in pole boxes at northern sites for jackdaw Coloeus monedula and in the south and east for kestrel Falco tinnunculus. Jackdaw was positively correlated with the number of nest boxes present, kestrel and stock dove Columba oenas were not. Jackdaw was negatively correlated with occupancy of the nest box by barn owl. The Wildlife Conservation Partnership monitored 159-200 nest boxes (‘pole-box’ or ‘A-frame’ in trees). From 2002 an additional 365-593 Barn Owl Monitoring Programme Network sites were also surveyed. Repeat visits were made to sites during the barn owl nesting season (April-October) to assess occupancy, gather breeding statistics and ring adults and chicks.


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