Swallows are back! These summer visitors, with their long, tapered tails, begin to arrive in the UK from Africa in early April – and the first of the year have been spotted at RSPB Geltsdale. They are a sure sign that summer is on the way, and are a welcome sight on the reserve. These hardy little birds begin breeding by early June, and once the first brood of chicks has fledged, often go on to raise a second or even a third brood. By early September, most Swallows are preparing to migrate back to Africa, though some remain here until early October. The long journey takes around six weeks, as the Swallows travel from the UK across western France and eastern Spain, then through Morocco, the Sahara Desert and the Congo Rainforest. They fly around 200 miles each day, feeding on flying insects, and many die of starvation along the way. If they survive however, they can live up to 16 years.
This week we have profiled four similar species: Swifts, Swallows, House Martins and Sand Martins, to help you tell the difference between them.
Swifts are dark, sooty brown and can appear black against the sky. They have crescent-shaped wings and a short, forked tail, with a bullet-shaped head. They make a piercing, high-pitched ‘scream’, so are often heard before they are seen. They fly high and very fast, in fact no other bird can fly faster in level flight (they reach speeds of 69 miles per hour), and they do everything while flying – drinking, feeding, mating and even sleeping on the wing, and refusing to land or come anywhere near the ground. They are sometimes seen clinging to a vertical surface and make their nests in roofs, buildings and cliffs, flying into their nests at speed by folding their wings in tight against their bodies. They use very little material to build their nests, unlike Swallows and House Martins, which form muddy ‘cups’ to nest in.
Swallows have dark blue, glossy backs, red throats, pale underparts and long tail streamers. They have longer wings than House and Sand Martins, and are fast and graceful in flight, spending most of their time on the wing and catching small invertebrates while flying. They can be seen flying low to the ground or level with the treetops and tweet and chirp from their perches. They nest in barns and other outbuildings, usually seeking out a ledge or beam for shelter and build a cup-shaped nest of mud which is camouflaged from predators.
House Martins are smaller than Swifts and Swallows, with a pure white underside, blue-black upper parts and a white rump. They have shorter wings than Swifts and Swallows, and a forked tail. They are most active in mornings and evenings and fly quickly at mid-height, usually in flocks. They fly low over water in wetlands and lakeshore areas, feeding on insects such as midges, mayflies and dragonflies, and zoom and in and out of house eaves, chirruping as they go. Like Swallows, House Martins build cup-shaped nests out of mud, preferring the outside of buildings, which look like cliffs to them. Like Swifts, they nest in colonies of dozens to hundreds of birds.
Sand Martins are the smallest of the four species and are dark brown with a white underside and a distinctive brown bar across the chest. They swirl and flap, rather than gliding, and can be seen flying over water and perching on overhead wires and branches. Unlike the other species, they nest by burrowing holes into almost vertical, dry, earthy or sandy banks. They nest in colonies and these nest entrances can pepper the surfaces of cliffs, gravel pits or high riverbanks.