Duchy Big Bird Box survey 2020

There seems to be a gathering momentum for provisioning nest places for cavity-nesting birds in new development, particularly in the south west, where the Duchy has an ambitious policy of providing an average of one nest place per dwelling. What is often lacking is adequate monitoring of these projects, but this report by Dr Thais Martins is very welcome, providing valuable data to support what we advocate.

Although it is early days, the results reported so far are most encouraging with significant numbers of House Sparrows, Starlings, House Martins and the first prospecting Swifts. This is a good example of community engagement in a citizen science project. See The Big Duchy Bird Box Survey

Photo: Hugh Hastings and the Duchy of Cornwall

Swifts often take longer to find new nesting places, but it bodes well for a future with vibrant Swift colonies in all the developments surveyed.

There is much detail in the paper highlighting occupancy rates by different species in different box types  and on different aspects.

As the data builds up over the years, this should provide some guidance as to what works best.

There is now a common understanding that a Swift brick can be considered as a 'Universal' bird box, and that sparrow terraces are not cost effective. The numbers of birds found occupying Swift bricks in Duchy developments confirm the universal nature of Swift bricks.

In this study, of 515  swift bricks, 192 were used by House Sparrows, Starlings and House Martins, but of 12 sparrow nest chambers in 4 sparrow terraces, only 2 were used. Although not significant at the 5% level it does point towards House Sparrows preferring Swift bricks

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