Emergency rations for rare bitterns

Louise Bentley is used to feeding birds at RSPB Fairburn Ings. Sunflower mixes, fatballs and peanuts are replenished several times a day to keep alive thousands of small birds in hard weather.

They are the usual suspects – blue tits, robins, bullfinches and blackbirds, plus more interesting birds like fieldfares and great spotted woodpeckers. Even the occasional water rail – a skulking bird that spends most of its time in marshes – emerged from hiding to peck around for seeds.

But on one of the coldest days of the winter a new name was added to the list of species attending feeders behind the reserve's visitor centre. A bittern. The bird was seen walking around beneath the feeding tubes and, Laura says, it set alarm bells ringing for the RSPB.

"Seeing a bittern come into the open like that made us think, well, if such a secretive bird is forced to break cover in this weather it is probably a sign that they're just not able to find food."

That thought set in motion an operation that has never happened at Fairburn before – buying fresh fish to feed the tiny number of bitterns which spent the winter there. And it continued even when the ice and snow began to melt. Similar operations have been taking place at the RSPB's Old Moor reserve in the Lower Dearne Valley, South Yorkshire, and also at the Yorkshire Wildlife Trust's Potteric Carr nature reserve near Doncaster.

The bittern is one of Britain's shyest birds, in complete contrast to its close relative the grey heron, which is a common sight on most lakes and rivers.

Its highly furtive nature is aided by the dense reedbeds and overgrown swampland in which it spends most of

its time.

In fact, the only reliable evidence that a bittern is present comes in the breeding season when a male is heard uttering its characteristic call – known as "booming" – to establish its territory. The deep foghorn-like call can sometimes be heard more than two miles away.

Centuries ago, bitterns are thought to have been widely distributed in the fens and marshes of eastern England, but declined as a result of factors like loss of habitat due to drainage, and hunting by humans for food.

It was once a much-prized delicacy, and there is a record of bitterns being served at a banquet for the enthronement of an Archbishop of York at Cawood Castle, near Selby, in the 15th century. And the legendary Victorian wildfowler on Yorkshire's River Derwent, Snowden Slights, is known to have shot them for sale on open markets at Leeds and York.

Hard winters have also accounted for huge drops in the population. It was extinct as a nesting bird in Britain by Edwardian times, but slowly returned from the Continent as a non-breeder.

In 1954, one was known to be near Goole, and in 1959 one was heard booming at Fairburn, but birdwatchers there had to wait until 1993 to hear one again.

Elsewhere in England the bittern re-established itself as a breeding species, a handful nesting in East Anglia and at Leighton Moss in Lancashire, and by the millennium there were 37 booming males heard at more than 20 locations.

In the last few years, there have been high hopes that bitterns will soon become Yorkshire's star breeding species. Large areas of new reedbeds have been established at Fairburn and at the RSPB's Old Moor reserve. At Potteric Carr the YWT has started a special Bittern Habitat Development Scheme costing 1.6m, partly funded by the EU, which involves planting 85 hectares of new reedbeds.

But the month-long big freeze could have wrecked the scheme. Reserve manager Jo Smith says: "Buying a bucket of fish a day is well worth it, and thankfully the bitterns caught on quite quickly to the fact that food was being put out for them. As a bonus, we got some lovely views."

There are four known individuals at Potteric Car, four others known to be spending the winter at Fairburn, while at RSPB Old Moor there is a single bird. Old Moor's site manager, Matthew Capper, says there have been daily visits to a local supermarket to buy fish. "It had been forced out onto the River Dearne to feed, which is not ideal territory, and has been roosting in willow trees at night because its reedbeds have been frozen over and could be accessed by predatory foxes."

Back at Fairburn, last week Louise Bentley continued her visits to a nearby supermarket.

"They sell fresh sprats and sardines on the fish counter, and the first day I went I bought a massive bagful. Before I set off I asked our warden, if there's no fresh fish shall I just get tinned sardines? He said, 'Oh no, I doubt the bitterns will be able to open the cans."

n RSPB Fairburn Ings lies close to the A1, a few miles north of the M62. From Leeds take the A63 then it is signposted off the A656. Access is free but for visitor centre opening times visit www.rspb.org.uk/reserves

n RSPB Old Moor is in the Dearne Valley, near Barnsley, South Yorkshire. Telephone 01226 751593 or visit www.rspb.org.uk/reserves

The Yorkshire Wildlife Trust's Potteric Carr reserve is open seven days a week from 9am to 5pm. The reserve entrance is less than a mile from Junction 3 of the M18. For further details visit www.potteric-carr.org.uk