Swift or swallow?

What's swooping around your eaves this summer? (Photo: Ben Andrew, rspb-images.com)

Alongside recent reports of dwindling numbers of butterflies and other insects this season, social media has been discussing a drop in swift numbers, too. Some people haven’t spotted any this year. 

I’m comparatively lucky, as there are two in my attic right now and I’ve counted 7 other regulars in the colony. But last year, if I remember rightly, instead of nine there were over 20. 

I’ve not seen many swallows, either - one or two in passing but if I think about it, probably less than usual. I don’t generally see house martins in my area, but there’s a good house-martin spot about an hour away that we visit each summer, so I’ll have a look when we go there, too. 

All three of these, along with the sand martin, are iconic summer migrants, flying in from Africa to raise their young in our less-scorching climate, snatching insects out of the warm summer air. 

Unlike the swallows and martins, swifts are not a member of the hirundine family, but as they live a comparable lifestyle and look pretty similar, they’re often confused with them. 

Our next issue of Wild Explorer magazine for young RSPB members will contain a handy ID guide to all four, but meanwhile, here’s a handy guide to spotting and identifying them.

Illustrations by Mike Langman (rspb-images.com)

SWIFT (Apus Apus)

UK Breeding population: 87,000 pairs

Identification: Dark sooty brown all over, but can look black against the sky. Boomerang-shaped wingspan and short forked tail. They have quite an unusual appearance, with bullet-shaped, almost dinosaurish heads, but you’ll often hear them before you see them - they use an unmistakeable, piercing, high-pitched ‘scream’ in full flight. 

Flight: High fliers - and extremely fast. No other bird can fly faster in level flight. They spend their lives in the air - sleeping, mating and drinking on the wing - and won’t land or perch, though can sometimes cling to a high vertical surface. They avoid coming anywhere near the ground. 

Nesting: Little slots leading into cavities within roofs, buildings or cliffs. They fly into these at speed, folding their wings on entry. Inside they use very little nesting material - no muddy cups for these guys.  

Where to look: Swooping or gliding at high altitude on warm, still summer days. Mornings and evenings they come lower down, and are particularly noisy and active around nesting colonies.

Helping swifts: With numbers reportedly falling, the RSPB would like to monitor swift sightings and nest sites, so please click here to report swift activity. If you find a swift on the ground it needs urgent help - click here to find out what to do. 

SWALLOW (Hirundo rustica)

UK breeding population: 860,000 territories

Identification: Distinctive long, forked tail like a toast-prong, with white underside, crimson throat and blueish sheen to the head and back. 

Flight:  Darting and gliding, often low to the ground or at treetop height. They often tweet and chirrup from perches. 

Nesting: Barns, lean-tos and other outbuildings with dark nooks and crannies for nesting. They’ll usually look for a ledge or beam among roof timbers that’s shelter from the elements, where they can build a cup-shaped nest that’s difficult for predators to spot. 

Where to look: Flying low to the ground over lowland fields and meadows, especially near lakes and rivers where there are lots of insects. They’ll also perch on telephone wires or wire fencing, and land on wet mud to scoop some up for nest-building. 

Helping swallows: Birds without Borders works across international borders to ensure safer passage for swallows and other summer migrants. Support the campaign here. You can encourage them to your garage or outhouse by ensuring a small opening, at least 5cm wide and 20cm wide and beyond the reach of cats; then fix a platform high inside the roof space. Put a plastic sheet below to catch droppings. Click here to find out how to encourage swallows to nest. 

HOUSE MARTIN (Delichon urbicum)

UK breeding population: 510,000 pairs

Identification: Smaller than swifts or swallows, with a white underside and ‘trousers’, and blue-black upper - except for the  the white rump on its back.

Flight: Most active in morning and evening, they zoom around at mid-height, usually together in flocks, coming down low over the water and fluttering in and out of house eaves, chirruping softly. 

Nesting: Like swallows, house martins collect mud to build cup-shaped nests, exploiting manmade buildings that mimicking the original cliffs, but (with the occasional exception) they go for the outside eaves rather than inside beams. Like swifts, they nest together in colonies, which can number dozens or even hundreds of birds. 

Where to look: Wetlands and lakeshore are a hotspot as house martins prey on flying insects often associated with wetlands - hoovering up midges, mayflies, damselflies and dragonflies as they swoop over the water. 

Helping house martins: With numbers in decline, you can buy ready-made house martin cups and install them under your eaves to give house martins a helping hand. 

SAND MARTIN (Riperia riperia)

UK breeding population: 100,000 pairs

Identification: The smallest of all the hirundines, these are dark brown but for a white underside divided by a distinctive brown bar across the chest. 

Flight: Swirling and flapping, less of the gliding. They fly mainly over water, and will also perch on overhead wires or branches. 

Nesting: Uniquely among our swallows, swifts and martins, these birds burrow holes into sandy or dry earth banks. They need a dry, near-vertical bank in a sea-cliff, railway cutting, gravel pit or high riverbank - though have also been known to occupy drainpipes poking out of walls, and holes in brickwork. Their tunnels lead to a nesting chamber and entire colonies of birds can pepper cliffs with these little entrances. These nests are protected by law. 

Where to look: Farmland and wetland, especially along rivers, lake systems and manmade gravel pits with suitable nesting banks. 

Helping sand martins: Click here to see how we provide nest sites for sand martin colonies - and how to build your own.