THE British Trust for Ornithology, which already has the world’s biggest bird data base on national species, is looking for volunteer bird watchers to help with its newest scientific project: tracking the movements of various species in winter and early spring.

It has been known for centuries, of course, that some birds migrate out of the British Isles and others come in to spend the winter months. But there is also a large scale movement of birds within the country, and these movements could become more dramatic as climate change brings warmer winters.

The winter census programme – a four year project – was launched last year and already changes in patterns of distribution are emerging for a number of species in both winter and the breeding season, says the BTO, which wants to collect more data for its Bird Atlas project.

For instance, stonechats have increased in the east, nuthatches, once confined to southern England, are becoming almost common in the Yorkshire Dales, and there is a hint that breeding lapwings are disappearing from the west and south-west.

• For more details, see www.birdatlas.net