A project to fit one of Britain's rarest birds with a radio transmitter will allow ornithologists the unique opportunity to track the creature as it winters in and around Waltham Abbey.o

A transmitter weighing nine grammes has been attached to a bittern at a gravel in West Cheshunt, Hertfordshire, as part of a research project carried out by local ornithologist Alan Harris, who can monitor its signal using sophisticated radio-tracking equipment.

The bird is one of Britain's rarest breeding birds and regularly spends its winters in the Lee Valley Regional Park. Researchers hope the transmitter will provide a revealing insight into its activities and needs while wintering in the park. It will also enable researchers to track the movements of the bird during the remainder of its stay and collate valuable new information on the behaviour of wintering bitterns.

Mr Harris said: "Until now, the breeding area of birds wintering in the Lea Valley was completely unknown. It remains to be seen if this bird returns to her Lincolnshire roots to breed or stays in the Lee Valley. Hopefully the transmitter will provide the answer to this and many other questions."

The project has been funded by Thames Water Utilities and the Lea Valley Regional Park Authority with support from the Royal Society for the Protection of Birds.

Although the tagged bittern is being monitored during its time in Lea Valley, its story began long before that.

When it was found it was already wearing a ring on its leg with a unique number enabling scientists from the RSPB to identify it as a female bird.

The bittern was originally ringed as a nestling in Lincolnshire on June 6, 2001, but its movements between that date and an almost certain sighting on November 2 last year are a complete mystery.

The discovery of a British-bred bittern wintering in Lea Valley is particularly encouraging since the likelihood is that any colonisation of the valey by breeding bitterns will come from British stock.

January 27, 2003 16:00