Swifts have incredibly short legs and tiny feet, which means that they are not really able to walk and cannot take off from the ground. Owing to this, Swifts preen, feed, drink, mate and sleep on the wing and only land to breed (which they do in inaccessible sites such as tiny cracks high in roofs). Recent research has shown that swifts fly as high as 10,000 feet when they are asleep, probably to avoid predation).
Often confused with Barn swallows and House martins (and other martins) but can actually be easily identified using a couple of key pointers. Barn swallows have long forked tails, which look like streamers and very obvious white underparts (with a rusty red bib). House martins also have white underparts and a distinctive white rump. Sand martins (much less common in urban areas) also have white underparts. Both martins and swallows frequently land on telegraph wires and fences – in which case they will not be Swifts!Record a sighting