Saturday 25 January 2014

Internal boxes with entrances fashioned from an air brick liner

From many points of view, built in nest-boxes are to be preferred to those hung on the outside of a wall, particularly if placed high up in a gable end within a roof-space. The nestboxes are secure, out of the sun and rain, and they provide a minimum of visual impact to the building. Although very easy to incorporate while a building is being put up, it is also not that difficult to retrofit them, but it does require some level of building skill. We have documented 2 examples here and here

[Postscript July 2015: A pair has raised 2 chicks in the the right hand box. The pair in the external heat-proof box has again raised 2 chicks]

The original double-walled external nest box and entrances to 3 new internal nest boxes
Model 400 air brick liner 220 x 200 x 65mm
Here is another idea using entrances made out of an air brick liner - this time the model 400 on page 10 of this PDF. This air brick liner has a hole 30mm high.

We previously described the success of a single, heat-proof nest box on the outside of Judith Wakelam's bungalow in Worlington. As Judith wished to have more nest boxes we decided to build 3 nestboxes inside the attic, rather than add more outside on this south-facing gable end.

Entrance fabrication
The air brick was cut up with an angle grinder, then the 3 component pieces were glued together with a resin glue, suitable for stonework. One can get at least 4 entrances out of 1 air brick liner.

A hole was made in the outer wall by removing 50mm from each side of a vertical bond in the brickwork, leaving a space big enough for half a brick - the size of the entrance piece. This can be done very neatly by drilling a hole through the mortar then using a sabre saw to cut the brick.

Bill Murrells installing the entrances. Photo Judith Wakelam
In this case, the inner wall was made of concrete blocks, so we chose to replace the height of a block with a nest-box, abutted against the outer wall with a waterproof membrane between the box and the wall. Alternatively, we could have used a 100mm core drill to make a hole in the inner wall providing access through a 100mm pipe to the nest box which would be hung on the inner wall.

Bill finishing off the installation. Photo Judith Wakelam
The nest boxes were made of weather-proof plywood. The removable wooden backs conceal a perspex 'window' to provide direct viewing when any birds become established.

Each box was fitted with a soft fibre-board nest concave.

#inserts #Cambridge

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