Gabor Lovei is a scientist who clearly prefers the field to the lab. His research site is a wetland reserve between the Danube and the Tisza, about 35km south-east of Budapest. Born and educated in Hungary and now living in New Zealand, Dr Lovei returns each year to the Osca Landscape Reserve, to join volunteers and students working on one of Eastern Europe’s longest running bird migration projects.

Hungary is an important stop-over for migrant birds. It is half way between breeding grounds and their Mediterranean departure point for a trans-Saharan flight. The reserve’s woods and reedbeds provide a vital refuelling point.

Data painstakingly collected from banded birds provide an early warning system of fluctuations in numbers and the state of breeding and migrating habitats.

Climatic change and loss of habitat have hit the birds hard. Dr Lovei estimates that numbers of migrants such as swifts, swallows, warblers, nightingales and thrushes have fallen by 60 per cent over the past 15 years.

This summer, Dr Lovei’s field assistants included four UK teachers on Earthwatch Millennium fellowships. These “ambassadors for science”, as he calls them, were selected for their commitment to environmental education, as well as their team spirit, adaptability and willingness to rough it. Most importantly, according to Lawrence Bee, education officer at the Hill End field study centre near Oxford and a member of the selection panel, they must show they will put the experience to good use in the community when they return home. A particularly fruitful way of doing this, he says, is developing school links.

Earthwatch is an international science and education charity that supports field research by recruiting paying volunteers, who contribute practical as well as financial help. The volunteers gain a unique insight into field research in often remote and inaccessible places, while the scientists receive funds and enthusiastic helpers.

Earthwatch not only makes scientific advances possible, says Dr Lovei, it ensures they are communicated to the public. So his work on songbirds is a much-needed indicator of environmental change, on which to base decisions about habitat management.

Founded in the United States in 1971, Earthwatch has since sponsored more than 2,000 expeditions in 118 countries. Thanks to a Millennium Commission award, 164 teachers and education officers received fellowships on Earthwatch projects this year and another 400 places will be offered to teachers and conservation educators over the next two years.

Many of the projects have enticingly exotic themes - India: Land of the Snow Leopard, Ecuador Cloud Forests, and Indonesia: Komodo Dragon, for example. But only the seriously-minded environmentalist should apply - these are rigorous investigations, involving hard and often repetitive work. “You’ll come back exhausted, but exhilarated,” says Mr Bee.

The basis of the Earthwatch fellowships is Local Agenda 21, one outcome of the 1992 Rio Earth Summit. The Osca teacher fellows, like most of their counterparts on other projects, personify the Agenda 21 slogan: “Think globally, act locally”.

Juliet Edmonds, a primary science lecturer at Brunel University, has worked with The World Wide Fund for Nature, the Royal Society for the Protection of Birds, Greenpeace and Friends of the Earth, as well as on other field research projects such as with the Sea Turtle Protection Society of Greece.

Another award winner, Steve Ashton, about to take up a post as education officer of the Cleveland Wildlife Trust, has spent the past nine summers working as a volunteer warden at Loch Garten, the RSPB’s osprey reserve in the Cairngorms.

It soon became clear that the time in Hungary would generate a fund of new experiences, information and research techniques. Within minutes of arrival the teachers were sent off to patrol the mistnets - 2,300m of fine nylon nets placed throughout the reserve. Hourly patrols started at 6am and finished at 9pm in almost total darkness, when the mosquitoes were at their most voracious.

Extracting a fragile warbler or vicious shrike from a tangle of feathers, claws and netting seemed an impossible task. But volunteers soon acquired the “bander’s grip”. They would deftly slip the bird into a small bag, to be taken to the ringing station for measurements (wing length, body fat, weight and so on), ringing with a numbered metal band and, finally, freedom.

More than 120,000 birds of 144 species have been ringed at Osca since 1983, and the resulting data computerised at the University of Budapest. Sister projects have been set up, also supported by Earthwatch volunteers, in the foothills of the Italian Alps and in the Tsavo National Park in Kenya.

Mistnet patrols and data-logging were the volunteers’ main duties, but they also took part in experiments to gather data on flight orientation and helped with an insect census. As well as broadening their horizons, they all welcomed the opportunity to take real-life examples back to the classroom.

Working alongside the UK volunteers at Osca this year were research students and scientists from Hungary, Germany, Poland, Finland and Kenya. For many, the forging of international friendships and the hospitality of the local villagers were as valued as the sense of having made a genuine contribution to the project.

Full-time primary or secondary teachers of any subject can apply for Earthwatch Millennium fellowships. Fellowships are also open to conservation educators and teachers at other levels and in special schools. Contact: Dr Pamela Mackney, Earthwatch, 57 Woodstock Road, Oxford OX2 6HJ. Tel: 01865 311601