Oliver Radcliffe
Why these birds need a hand
Swifts, swallows and martins are the sound of a British summer. The screaming parties of swifts over a town roof in July, swallows chattering on a telephone wire, house martins ferrying mud to the eaves — these are the sights and sounds that tell us the season has properly begun.
They are also in trouble. Swifts have lost well over half their British breeding numbers since the mid-1990s, and house martins have declined sharply in the same period. Swallows are faring slightly better but are still down. The reasons are tangled: fewer flying insects, lost nesting sites as old buildings are repaired or demolished, and a changing climate that makes their long journeys riskier than ever.
The good news is that these are birds we can genuinely help. They nest on our buildings, hunt over our gardens and farms, and respond quickly to a bit of practical kindness. Here is what you can do before they arrive in April and May — and what to avoid while they are here.
Know who you are helping
A little identification goes a long way, because each species needs something slightly different from you.
- Swifts are the dark, screeching ones, arriving in early May. They never perch, and they nest in dark cavities — gaps under roof tiles, behind fascia boards, in old wall voids and specially made swift bricks. They leave by early August, sometimes sooner.
- Swallows have long tail streamers and a deep red throat. They nest inside buildings — barns, stables, old garages, a porch with a window left ajar — building a cup of mud and grass on a beam.
- House martins are the neat blue-black and white ones with a white rump, nesting in groups under the eaves of houses in mud cups, often raising two or three broods well into September.
- Sand martins are our smallest and earliest, nesting in colonies in sandy riverbanks and cliffs, and increasingly in purpose-built nesting banks and pipes in quarries and gravel pits.
Strictly speaking swifts are not swallows at all — they are closer to nightjars — but they share the same habits: they eat only insects taken in flight, and they cannot afford to waste a day.
Put up nest cups and boxes
If you have smooth eaves with nowhere to build, house martin nest cups are the single most effective thing you can do. Fit them in sheltered groups of two, three or more, at least two metres above the ground, on a north or east-facing wall where they will not bake in afternoon sun or be hammered by driving rain. A small ledge of mud or a smear of soil inside helps the birds settle in. Keep them clear of windows and washing lines so there is a clean flight path in.
For swifts, a box on a wall or under the eaves at five metres or more is worth trying, but swifts are site-loyal and slow to colonise new places. Playing swift calls from a small speaker beside the box on warm evenings in May and early June dramatically improves your chances. Point the entrance away from the prevailing wind, give the birds an unobstructed approach, and be patient — it can take a few seasons.
Swallows need a door or window that stays open, or a stable with a permanent gap. A simple wooden shelf fixed to a beam, ten to twenty centimetres below the ceiling, gives them a base to build on.
Protect old nests and old eaves
An old house martin nest is a valuable thing. Birds frequently return to repair and reuse nests from previous years, and a nest cup fixed underneath a failing mud cup will catch the young if it collapses. Do not knock nests down in winter out of tidiness.
All wild birds, their nests and their eggs are protected by law while in use, so plan repairs carefully. Roof work, pointing, fascia replacement and painting under eaves should be done between September and March. If scaffolding has to go up in summer, ask the builders to work away from active nests and to leave gaps open. When you are repairing, try to retain the small openings swifts use, or fit a swift brick instead of sealing the gap for good.
Let the insects live
A swift needs roughly twenty thousand insects a day to feed a growing brood. Every spray, dust and pellet removes food from the chain.
- Avoid garden insecticides, especially blanket sprays and those aimed at flying insects. Let a few aphids live; the blue tits will deal with them.
- Leave an area of long grass and native wildflowers to flourish through summer, and cut it in late August or September.
- Dig a pond, however small. Still water hatches clouds of midges, mayflies and damselflies — perfect swift food.
- Keep a muddy puddle or a damp patch of bare earth in the garden. House martins need mud for building, and dry summers make it scarce.
- If you keep livestock, talk to your vet about treatments that leave dung insects intact. Swallows hunting low over cattle pasture depend on them.
Small things that add up
Record what you see. Reports of nesting swifts, swallows and martins go to your county bird recorder or local records centre, and those records shape planning decisions and conservation work in your area.
Talk to your neighbours, too. These are colonial birds, and one household putting up a cup or leaving a barn door ajar is good — a whole street doing it is far better. The birds do the rest, and they repay you with the best free entertainment of the English summer.
