Wednesday 9 January 2013

Swift nest boxing results in Cambs & Suffolk

Written by Dick

As there is not much Swift activity around right now, we thought it might be worth reviewing the results that have been achieved with Swift nest-boxing projects. Most of these have been in Cambridgeshire, with a small number in Suffolk, the county next door.

The table below summarises the results in 2012, though in many of the sites, first occupancy was in a previous year:

Breakdown of Swift nest boxing projects.
The figures are for boxes available before or during 2012.
The large majority of these projects were installed in 2010 or later.

We have explored 2 factors which might influence success rates, first the playing of attraction calls and second whether the project could be regarded as mitigation for nest sites recently lost in the near vicinity.

Although only 13% of boxes are occupied, this figure is influenced by a small number of projects with a large number of boxes, some of which only have a few boxes occupied so far e.g. "The Swifts", Fulbourn (157 boxes, 27 occupied), Edgecombe flats (71 boxes,  2 occupied), St Mary's Church, Ely (96 boxes, 21 occupied plus 11 possibly occupied with some feathers) and the Cambridge Swift Tower (100 boxes, none occupied). Hopefully, over time, these will achieve their full potential. However, 104 new pairs of nesting Swifts is something to be pleased about.

We are encouraged by the number of sites with at least 1 pair of Swifts: 38% of all sites. Of these, those where attraction calls were played, there was a 43% success rate. Those where nest sites had been lost nearby had success in 5 out of 6 projects.  It turns out there were no sites where both factors apply.

If one combines the sites where there was some attracting factor, then 20 out of 41 sites (49%) were successful. The 12 sites with no attracting factor had no success whatsoever.

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