ONE bittern's booming in the reedbeds - and another's giving the odd grunt of encouragement.With two male birds in evidence, wardens at Titchwell RSPB reserve hope the secretive birds, which are among Britain's rarest species, will breed this spring.

ONE bittern's booming in the reedbeds - and another's giving the odd grunt of encouragement.

With two male birds in evidence, wardens at Titchwell RSPB reserve hope the secretive birds, which are among Britain's rarest species, will breed this spring.

Last year, 76 booming males were recorded across the country, with East Anglia remaining one of the once common bird's last strongholds.

The number of booming males heard around the country is taken as one of the best indications of how many bitterns remain.

Titchwell's dense freshwater reedbeds are maintained to provide plenty of cover and an ample supply of rudd - small, surface-swimming fish which are one of the bittern's favourite foods.

Dave Taylor, from the reserve, said: “We've got a boomer and a grunter at the moment. When the male gets ready to breed, they have a period before they boom of making a grunting sound. We've seen two male bitterns. We not only have two out of the 76, we're one of only 40 sites where they breed.”

All now depends on whether the male bittern's call - imagine blowing across the open top of a milk bottle - can successfully attract a mate.

Bitterns returned to Titchwell after a lengthy absence in 2005. The birds, which resemble a small brown heron, are normally so secretive it is difficult to establish whether they have bred successfully.

One clue is the adults seen crossing the path leading through the reserve, as they sometimes leave their reedbed and fly further afield in search of food.

Coastline at Titchwell is being remodelled to help protect the freshwater reedbeds from rising sea levels and increasingly frequent storm surges. Work on the �1m project is due to start later this year.