Smaller than swallows and swifts, sand martins are the first to arrive from winter nesting grounds south of the Sahara. They arrive in March after an epic journey of up to 2,500 miles and are found across the UK, nesting in colonies from a dozen to several hundred pairs on rivers, lakes and flooded gravel pits. They are agile fliers, feeding mainly over water on small insects, mainly gnats and other flies. The sand martin's twittering song is continuous when the birds are on the wing.
Sand martins nest at the end of tunnels up to four feet long, bored into sand pits, gravel pits, and sea cliffs. A convenient defunct drainage pipe will also fit the bill. They line their nests with vegetation and feathers. Sand martins will keep coming back to the same site for years. They lay four to five eggs in late May or early June, with eggs hatching after around two weeks. Approximately 20-24 days later, chicks will fledge. Sand martins usually have two broods each year, the second in August. Their lifespan averages two years.
Look out for them perching on overhead wires or branches in late summer and early autumn, the young exercising their wings. They're eager to start their journey back south. By the end of September, they're all gone.
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| How to identify martins, swallows & swifts. |
Where can you see sand martins? In spring or late summer, sit on one of the middle benches at The Quay in St Ives. So long as there are no boats moored, sand martins will swoop in close to access their nests in pipes along the mooring wall. Or walk across St Ives bridge. About 150 yards along the left-hand path of the New Bridges, you'll be surrounded by sand martins swooping into their nests in pipes along the outer wall.
For more nature topics and walks, click Cambridgeshire Nature Watch.
