Saturday 11 January 2020

Modified Schwegler 1MF

The Swifts Estate nest boxes in Fulbourn Cambs are one of the most successful projects in the UK: 276 nest boxes in 250 dwellings are home to 100 pairs of Swifts, together with House Sparrows, Great Tits, Starlings and House Martins.

The nest boxes comprise 168 custom made internal boxes and 54 Schwegler 1MF double boxes (108 nest chambers). However, 90% of the Swifts are in the internal boxes with only a handful in the Schwegler 1MF's. (See here for internal nest box design).

2 internal entrances near the top of the gable
and the modified Schwegler 1MF. The other side
of the gable is a mirror image (click to enlarge)
So we mulled the idea of modifying the entrances of the Schwegler 1MF's to be more like the internal boxes.

Andrew Tristram, who lives in another part of Fulbourn also had 2 Schwegler 1MF's on his gable, which attracted breeding Starlings. He reduced the entrance size and played Swift calls, but still no Swifts. We then installed 4 Cambridge System internal boxes inside the roof space, and 2 pairs of Swifts moved into them.

As an experiment we then made 2 new entrance plates for the 1MF's with horizontally facing entrances, with a similar appearance to the Cambridge System entrances.

Although it is too early to draw firm conclusions, 1 pair of Swifts moved into 1 of these modified boxes. We intend to replace more of the 1MF entrances, but we need to wait another season to get any more data, so we thought we would publish this now.

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