Today Anglian Water scientists, along with our partners at the British Trust for Ornithology, are launching our latest season of tracking nightingales. The birds are being fitted with geo-locator tags at Grafham Water and the information will help scientists to find out more about why these birds are in decline. Paul Stancliffe from the BTO explains more:

Since the mid-1990s we have lost almost half of our breeding nightingales, with the real possibility of extinction in several counties on the northern edge of its British range. It was fairly widespread in Lincolnshire, and in several Midland counties but now its stronghold is pretty much confined to the south east, and even here numbers are falling.

It is unclear what the exact cause behind this decline is but there are likely to be a combination of factors, including loss of habitat and pressures on migration to the African winter quarters. When nightingales were more widespread one of the main habitats used during the breeding season was woodland but as the number of these enchanting birds has fallen, scrub has become the dominant habitat used.

Woodland might have always been sub-optimal habitat for nightingales, and as the population dropped the need to spread out into woodland is less, with the remaining birds using the ‘better’ scrub habitat. Anglian Water has been managing scrub for nightingales for several years and have had great success at their sites, encouraging a strong breeding population. For more information, please visit

Nightingales arrive back in the UK around mid-April and begin to leave for Africa in late August/early September. During the six to seven months that they are outside of the UK very little is known about them, but with the help of Anglian Water, the British Trust for Ornithology are beginning to fill in gaps in that knowledge using very clever technology.

Since 2009, several nightingales have been fitted with geolocators before they depart on migration. Geolocators are shirt-button sized devices that weigh less than a gram but contain a clock, a calendar and a light sensor. By collecting and storing data using all three of these, scientists at the BTO can analyse them and determine where it was collected, and from this produce a track of their movements.

So far, thirteen of these ‘migrations’ have been recovered from the devices, and we now have a better idea of what nightingales do. But the sample size is still too small to draw firm conclusions. So, during the next two or three years, the BTO and Anglian Water hope to fit more of these amazing tags onto nightingales to help fill in the remaining gaps in our knowledge, that in turn will help to inform conservation policy for this most iconic of species.

Posted by Anglian Water