Migratory birds are building a diverse range of nests at Thatcham Nature Discovery Centre in Berkshire after flying thousands of miles from Africa.

With bodies shorter than a ball-point pen, the first to complete their impressive journeys in March and mid-April were the sand martins and the reed warblers. They have now been joined by the larger, silver-winged common terns.

All will have come to England to pair up and raise young before travelling back to Africa in the summer.

RSPB project officer Lynsey MacFarlane said, 'We can already see lots of sand martins building their nests in the purpose-built artificial bank next to the Centre.

'It's incredible to see them working so hard after having just flown all the way from Africa.'

'We can already see lots of sand martins building their nests in the purpose-built artificial bank'

Like other birds, sand martins are very particular about where they nest. They burrow holes in vertical sandy banks, often near rivers.

Lynsey said: 'Sand martins are perfectly capable of building their own nests. But their global population is declining, probably due to climate change and other factors causing drought in their African wintering grounds.

'By providing extra suitable nest sites where they can breed and raise their young in spring and summer, we can give them a boost while they face the challenges of the changing environment.

'And even though their African wintering grounds may seem out of reach, we can also help protect them from further climate change by reducing our carbon emissions.'

The common terns have also suffered recent declines. Climate change and overfishing are the suspected causes.

Also known as 'sea swallows', they make their nests by scraping out a shallow hole in shingle or sand. Staff at the Centre are have made special rafts for them to nest on.

Thatcham also boasts the largest areas of inland reedbed in southern England. This is where Reed Warblers will soon be building their cup-like nests, suspended between reed stems.

Monitoring work by the Newbury Ringing Group has helped reveal that reed warblers nesting in Berkshire fly as far south as Ghana in West Africa for the winter.

Lynsey added, 'Migratory species like these are a reminder of the strong links between habitats here and in far off parts of the world. These birds need both in order to survive.'

Lynsey is running free Date with Nature events at the Centre from 11 am to 4 pm most Saturdays and Sundays until the end of September. Visitors of all ages can come and see the nesting birds, try a little pond dipping, and learn about the other wildlife supported by the variety of habitats at Thatcham.

Early risers can also enjoy the dawn chorus of songbirds near the Centre. This is at its most powerful in May.

The Centre is open Tuesday to Sunday from April to October between 10.30 am and 5 pm. Entrance is free, but there are charges for some activities.