Saturday 11 July 2020

Rutland Swift Boxes

Tim Collins lives in a village just 3km from the shores of Rutland Water. In the last 17 years, he has built a thriving colony of 26 pairs of swifts in DIY nest boxes of his own design.

Tim's success is down to a combination of his proximity to a major source of food, and clearly the Swifts like his nest boxes. Tim's nest boxes are notable for their extreme simplicity - a simple box with a bottom entrance next to the wall. It is not even a complete box as it has no back. The version that goes under the eaves has no roof either.

While Tim’s boxes are all bottom opening, the design could easily be adapted to be front opening if you believe the swifts in your area prefer that design. An interesting experiment for a new colony would be to install a mix of front and bottom opening boxes and see which are occupied first.

In Tim's own words:

The 'Rutland' Swift Box
Unlike most other swift nest boxes the 'Rutland' swift box has its entrance hole in the floor of the box. This may look odd to human eyes however people don't think like swifts or know what swifts are looking for when searching for a nest site. The design has been developed from experience gained since 2001 at a growing nest box colony in a village close to Rutland Water. Our swifts really seem to like these boxes; the more we put up the more breeding pairs we attract.

The Rutland Swift  box (click image to enlarge)

The box is designed to mimic the appearance of many 'natural' nest sites in older buildings, such as the gap between fascia boards and the walls of the house, that require the swift to make a final upwards approach to the entrance hole. It initially drew on some suggestions in an old edition of the British Trust for Ornithology (BTO) nest box guide however we have evolved the design as we expanded our own swift colony (all in nest boxes). In 2020 we had 24 pairs breed in these bottom opening boxes, so in this part of the country it is clearly a design liked by swifts!!

The Design
The nest boxes are simple to make and install under the eaves of a house. The basic design is effectively only a 'half box', sealed at both ends and makes use of the wall of the house and the existing soffits to form its back and roof. Our own boxes are made from planed softwood timber however you could also use marine plywood. Once built the exterior of the box is painted, ours are white as this matches the colour of our house's fascia boards and soffits. White is also the best colour to use if the box will be exposed to direct sunlight as it helps reflect light and so reduces the risk of overheating. If you do decide to paint your boxes it is also worth using good quality exterior grade primer, undercoat and gloss as experience shows that this wears better and so reduces repainting requirements.

Basic materials:
A planed softwood plank 19 x 144mm x 1800mm (readily available at most DIY stores)

Panel pins - 40mm - used to do the initial fix as the box is assembled, can either be removed or driven home with a nail punch and the hole filled with wood filler.

Brass screws - to hold the box firmly together
Right angle brackets (ideally plastic coated or brass to avoid rusting)

Cutting List (all cut from the 19 x 144mm wide plank)

1 x 500mm
1 x 540mm
2 x 144mm

The precise length of the box is flexible and individual boxes should be tailored to match the available spaces. It is however worth remembering that prior to fledging young swifts like to stretch out and exercise their wings; as swifts have a wingspan of 42 - 48cm a box length of about 50cm is a good choice. It is perfectly acceptable to make the box smaller if that is the available space; Swifts often nest in really small spaces. The images below show both the basic design and a variation on it.

The size of the entrance hole is important (to avoid other species such as starlings intruding), we've tried various shapes and have now settled on a 28 x 65mm slot; this is easily cut with an electric jigsaw (but can be done by hand with a fretsaw). The entrance hole is placed at one end of the box, we find it best to locate it so as to maximise an open approach to the box (away from any drainage pipes or chimneys)

Once finished the box is fixed to either the wall or the soffits with right angle brackets.

Rutland Wall Box
This variant is for cases where there are no suitable eaves. It is a good idea to give the roof a water-proof coating of some sort.

Rutland Wall Box

Tim Collins
June 2020

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