Teme Valley Musings, February 2020

by Stephanie Mocroft

My topic for this month is the garden bird-box. Over the past twelve months I’ve been asked a number of times how to site different types of bird-box, so I’ve put together some information, mainly from RSPB and Wildlife Trust leaflets, to try and guide people who have either made or bought a bird-box and want to achieve the best results from it.

Gardens may not provide many natural opportunities for birds’ nests as many birds like to nest in a hole in an old tree and these are scarce in the average garden. The nest box creates an alternative family-raising space and there’s no doubt that there’s great enjoyment to be had from watching pairs of birds gathering nest material, then flying in and out with food for their chicks. The ultimate prize is to see the fledglings take to the wing, although it’s even possible to see into boxes for a sneak preview before this happens, if you’re handy with technology.

As a general rule boxes should be put in a shady place, either fully shaded or at leastprotected from hot sun and south-westerly winds, so facing between north and east is best. They should be relatively hidden, but accessible to their occupants. There should be a clear, safe flight-path to the entrance,which should be situated at least two metres above ground, this latter to deter predators. Autumn is the best time to put up a box as it gives potential users the chance to try it out as a winter roost, before moving in, hopefully to build a nest in the spring.

Boxes of different sizes and with different diameter entrance holes cater for different species. The most likely birds to be attracted to a garden box are tits, house sparrows, starlings, robins and house martins. 25mm entrance holes attract blue, coal and marsh tits. 28mm holes attract great tits and tree sparrows. 32mm holes attract house sparrows and nuthatches, 45mm holes starlings, and 50mm holes great spotted woodpeckers.Some birds like boxes with an open front. Spotted flycatchers favour a 60mm front panel, 100mm front panels attract robins and pied wagtails and 140mm front panels are appreciated by wrens.

For heights, tit boxes should go on a wall or tree 2-4m up; house sparrow boxes, in multiples as they’re gregarious, up under the house eaves and owl boxes, if you’ve a huge tree, 3-4m up. Having put up a box, annual maintenance is advised, otherwise pests and parasites can build up and annoy your tenants. Clear away debris in autumn and rinse in boiling water, then leave to dry before replacing the lid, but don’t use any insecticides or flea powder.Your avian visitors will need plenty of food to fuel a growing family, so don’t forget to provide food and water for them too.

And finally, to answer the question “where do I site a bird box to attract mandarin ducks” (yes, they nest in trees!), the answer is, 10 feet up in the fork of a big tree and up to 20 metres from water – many thanks to the TVWG’s Geoff Wookey for that one!