Nightingale in full song. Photo by Amy Lewis BTO

First-year findings from a high-tech study in Cambridgeshire are helping scientists unlock the secrets to saving one of the UK’s most enigmatic and fastest disappearing birds – the Nightingale.

Only 6,000 singing male nightingales remain in the UK, a decline of around 52 per cent since 1995. But now for the first time, thanks to an Anglian Water-funded study of nightingales at Grafham Water and The Fens, scientists have been able to map the bird’s epic 3,000-mile journey to spend the winter months in Africa, giving them new insight into why their numbers in Britain have fallen so markedly.  

Remaining strongholds for the birds in Britain are south-east England and East Anglia, but even these are under threat from development and require careful conservation and management.   

The significance of the East Anglia region to the nightingale’s future prompted Anglian Water to team up with the British Trust for Ornithology (BTO) and Bedfordshire, Cambridgeshire, and Northamptonshire Wildlife Trust, which manages the nature reserve at Grafham Water, to track the nightingale’s migration habits and help scientists understand why numbers are plummeting.  

Last spring, 10 nightingales from Grafham Water and The Fens were fitted with high-tech ‘geolocators’ to gather data about their migratory journey. One year on, scientists are delighted that two-thirds of the birds returned safely, with trackers in tact, providing valuable data for the study.  

Data from the trackers will be analysed fully by the autumn but initial findings show the nightingales, which weigh just 21 grams – about the same as a £2 coin – make a 3,000 mile journey to spend the winter months in Senegal and The Gambia, flying via northern France and Spain to Gibraltar, and then along the African coast to avoid the long flight across the wide, dry Sahara Desert.  

The tiny birds complete the journey in around six weeks, and by March, embark on the arduous journey back to the UK to breed – often returning to the exact same bush or scrub as the year before.  

The findings back-up beliefs of conservationists that some causes of the nightingale’s decline could lie in changes to its favoured habitats along the route to their African wintering grounds.  

Mike Drew, Anglian Water’s Biodiversity Action Plan Scientist, said: “Having a better knowledge of the nightingale’s exact migratory route and stopovers will help us understand what problems they are running into and enable us to preserve the habitats along the way, so they have good quality breeding grounds and ‘service stations’ to feed and rest at.  

“It’s astonishing that such a little bird can make such a long and dangerous journey with only a handful of stopovers. To put this amazing feat into perspective, the Ospreys, which breed at our Rutland reservoir and are a much, much larger bird, make a similar trip to Senegal in 16 days.  

“Nightingales show remarkable tenacity and resilience, but a decline in habitat is starting to take its toll and that’s why this project is so important to conservationists in the UK and all over Europe, and ultimately to the nightingale’s future.”  

Dr Chris Hewson from the BTO said: “We have known for some time that nightingales were in trouble. Their numbers have dropped by a half since 1995 and continue to fall.  

“Not only that, but the bird’s range is also shrinking, with almost all of them now found in the South and East of England. We know that some changes taking place here in England are very likely contributing to the Nightingale’s decline but we also need to find out whether they are being affected by changes taking place in the places that they visit during the nine months of the year that they are not here. This study in an invaluable step towards doing that.”  

Anglian Water has a long history of supporting nightingale conservation work and for a second year in a row, many Anglian Water workers have been out of bed early to listen out for the songbirds on the company’s Grafham Water reservoir site as part of another national BTO nightingale survey.  

The water company has also funded a ‘hotspot survey’ in The Fens, the findings of which will be available in autumn, to understand what makes this area so attractive to the birds.  

Mike added: “These wonderful little birds are clearly in a lot of trouble and with the Anglian Water region so important to them, it is only right we do all we can to help their conservation.  

“We are very proud that the work we’re supporting is providing so much useful information about how we can help the nightingale in England. Now the information is going to help us to understand how to help them when they are away from our shores too.”  

The Nightingale project is run by the British Trust for Ornithology, funded by Anglian Water and supported by the Bedfordshire, Cambridgeshire and Northamptonshire Wildlife Trust which manages the habitat at Grafham Water reservoir on behalf of the water company.