A booming bittern, one of the UK's rarest birds, has been heard at the RSPB's Titchwell Marsh reserve for the first time since 1991.
Experts hope the bittern population will reach 100 males by 2020
The reserve has the second largest reedbed in north Norfolk, and has just been improved for the bird by lowering the reedbed and introducing fish.
In Suffolk, nine bitterns are now booming at Minsmere and another two at North Warren near Aldeburgh.
The bittern population has increased fivefold over the past seven years.
In 1997 only 11 bitterns were found during a UK-wide survey, but in 2004, experts counted 55 bitterns at 30 sites.
Researchers use the male bittern's booming call as a method of estimating the population of this otherwise secretive bird.