Building a nestbox for house sparrows

Modern housing often prevents nesting opportunities for house sparrows and other species. Erecting a nestbox will provide a much needed home for your local sparrows. House sparrows will begin prospecting for nest sites as early as January in preparation for nesting in April through to August so aim to have your box sited as soon as summer ends in preparation for the next year’s brood. Don’t forget that you need a 32mm sized entrance hole to accommodate house sparrows. Avoid south facing walls and put the nestboxes as high as you can under the eaves of your home.

Before you make your birdhouse
It is worth investigating which birds are regular visitors to your garden. This will help you to determine what size birdhouse you wish to build, and how big the entry hole will be as some species of bird – as well as squirrels – will rob a nest and can kill the chicks.

  • 25mm (1inch) is large enough for coal tits, marsh tits and blue tits only
  • 28mm is big enough to allow great tits
  • 32mm will allow sparrows, nuthatches and finches access to the birdhouse

You’ll also need to choose a suitable site for your birdhouse. It needs to be ideally 2 to 3 metres above ground level at the very least. The birdhouse should be sited away from ledges or bushes where predators like cats can gain access to them. You should also consider where the prevailing winds and rain come from, and site your homemade birdhouse in a sheltered spot. The site should be quiet, away from feeders with a clear flight path.

Angling the birdhouse slightly so that the rain will run off away from the entrance may help. The birdhouse design described in this article has an overhanging roof, which will aid water drainage. Also make sure that the birdhouse won’t be baked in any sunshine. Ideally a north to south easterly facing direction will avoid any weather-related problems.

Why make your own birdhouse ?
House sparrow nest boxA simple design is always best. Birds want function over aesthetically pleasing houses, and will only make use of a house that meets their needs. Your homemade birdhouse or nestbox needs a few fundamental features – an entry/exit hole or space, a small drainage hole in the bottom for any water that finds its way in and a tightly fitting lid. This means that cost of your homemade birdhouse will be minimal.

The birdhouse should be waterproof, but try to avoid being overzealous with any wood preserver or treatments, as the smell can be overpowering and deter birds. You should also only use water-based preservatives and preserve the outside of the birdhouse and away from the entrance hole.

It’s worth bearing in mind that perches that are commonly found on commercial birdhouses are also not necessary under the entrance/exit hole. They will only serve to encourage predators.

Building your birdhouse
The birdhouse (or nest box) is really quite easy to make. The materials you’ll need are:
• Wood or Timber Off Cuts: 12-15mm ply is an ideal material for a birdhouse. You will need one length 15cm in width and 150cm long.
• Sealant: A silicone-based aquarium sealant is best, and you must make sure that the brand you choose does NOT contain any fungicides.
• Galvanised Nails or Brass Screws.

You will also need the following equipment:
• Drill with 10mm wood drill, 25mm, 28mm or 32mm drill bit
• Pencil
• Tri-Square (any wonky cuts can cause drafts in the birdhouse)
• Measuring Tape
• Saw

The whole birdhouse can be made from one length of wood.
The first part of the wood length will be cut up to form the birdhouse sides and roof. The wood should be divided up as follows: Birdhouse Sides: From the bottom, measure and mark 20cm on left hand side and 25cm on the right hand side. Then from your 20cm mark, measure a further 25cm on the left, and on the right, measure 20cm from your original 25cm mark. This will create two sidepieces with a diagonal sloping roof. Then mark up the front section of the birdhouse – this should be 20cm in length.

The next part of the wood will form the roof, base and back of the wood and should be cut up as follows: Measure a further 21.2cm and mark off. This will become your roof. Another 11.2cm measurement will form the base section of your birdhouse. The remaining 45cm will then form the back of the birdhouse.

Before you cut all the sections out from the wood, be sure to put in your entrance/exit hole. The drill bit you use will depend on which birds you intend to use the nestbox (see ‘Before you make your birdhouse’). Make sure that the hole is at least 12.5cm from the base of the birdhouse, as this will help to keep the chicks safe. The cut that forms the front panel should also be roughed up on the inside to assist young birds to climb out. Using the 10mm drill bit, you should drill in a couple of holes in the ‘base’ section to help with water drainage.

Once you have cut out the sections, you can then screw all the parts together and seal. Make sure to leave at least 4 or 5cm at the top of the birdhouse on the back so that it can be screwed into place. The lid should be hinged with a thick strip of rubber on the outside and kept closed with a catch. Do not be tempted to look in on the nestbox until you are absolutely sure that the birds have vacated, as you might cause them to abandon their young.

This article in its original form can be found at

Who killed the cockney sparrer?

I was recently interviewed by BBC radio regarding my thesis findings and asked to contribute to a programme investigating the causes of the decline of the urban House Sparrow. The Radio Times highlights the programme’s value and their summary gives a good overview to some of the issues pertinent to urban species.

Who Killed the Cockney Sparrer?
Wednesday 18 March 9:00pm – 9:30pm BBC Radio 4
House SparrowNature detective Tom Heap investigates who, or what, is killing the common sparrow. Once one of our most common garden birds, it is now a rarity. Since the mid-1990s, London alone has lost more than two thirds of its sparrows and there are similar cases in Bristol, Edinburgh and Dublin. In an attempt to unravel the mystery, Tom delivers a sparrow corpse to the laboratories of the Zoological Society and observes the autopsy which demonstrates that the cause of death is not always what it seems. He speaks to experts from various conservation bodies including the RSPB and the British Trust for Ornithology to weigh the latest scientific evidence. Tom finds out about the chief suspects, including cats, sparrowhawks, unleaded petrol, mobile phones, garden make-over programmes and loft conversions.

A full copy of my doctoral thesis investigating the causes of the decline of the urban House Sparrow (Passer domesticus) in Britain can be downloaded from or viewed at my website.

Ecobuild 2009

EcobuildEcobuild is the world’s biggest event dedicated to sustainable design, construction and the built environment. The exhibition was held at Earl’s Court Exhibition Centre in London between 3rd and 5th March and is now in its 5th year. There were 800 exhibitors, as well as conference and seminar sessions.

I attended and presented a talk on ‘The provision for birds in buildings; turning buildings into bird friendly habitats’ within the seminar topic ‘Practical biodiversity – Making it happen’. The presentation highlighted the design options available and practicalities of how you incorporate birds within the design of buildings.

A full copy of my presentation can be obtained by emailing me.

Why house sparrow research?

House Sparrow nest boxHouse Sparrows (Passer domesticus) were once a plentiful species but in recent years their numbers have dropped alarmingly, so much so that they are now a red listed species, which means that they are a bird of conservation concern in the UK.

What are the wider implications?
House sparrows have lived alongside man for thousands of years and can be seen as a barometer for the state of man’s environment, almost like a miner’s canary.

Why does it matter?
If House Sparrow numbers are declining what is going wrong with/in our environment?

Why are they worth saving?
House Sparrows are embedded within our culture and lifestyle; they are prevalent in our literature, art and even merit a mention in the Bible. To lose this species would be to lose an aspect of ourselves and of man’s history.

What can you do?
Subscribe to this blog for helpful tips. Support organisations such as RSPB and Natural England who fund vital research.