Bitterns, known to be Britain's loudest bird due to their "remarkable" and "booming" call, have made a comeback in London, according to conservationists.
The UK's population of the secretive bird, which is often difficult to spot due to its effective camouflaged plumage, has grown from just 30 breeding pairs to more than 200 thanks to the London Wetland Centre.
The centre, in Barnes, provides large undisturbed reedbeds so the birds can hunt and breed freely, making it the only place bitterns can be seen regularly in London during winter.
The population of bitterns in Greater London has at least doubled in the past two decades, thanks to the increase of reedbeds in the city, London Wetland Centre told the Standard.
The centre has constructed reedbeds with small pools, which provide an ideal habitat for bitterns. As a result, more and more birds are spending their winters in London.
Reserve manager Adam Salmon told the BBC: "With its numbers steadily rising, the bittern is a true flagship species for wetland conservation - proving that if we work to protect and restore precious habitats we can turn the tide on extinction."
Bitterns move silently through reeds at water's edge, looking for fish, according to the Royal Society for the Protection of Birds (RSPB).
"The males make a remarkable far-carrying, booming sound in spring," the charity said.
The birds' very small, reedbed-dependent population make it an amber list species. It is illegal to intentionally recklessly disturb them.
The species was pushed to the brink of extinction in Victorian times when their reedbed homes were drained for reservoirs.
The heron is described as "shy" and being a "master of blending in" by The Wildlife Trusts, but it "does sound like a booming foghorn when it calls so can often be heard if it cannot be seen".
The birds can also be spotted in East Anglia, Kent, South Wales and North West England.
Three common white storks are also being introduced to the London Wetland Centre.
The three common white storks, which are rare in the UK and much of Europe, are being introduced with the hope that they will form part of a breeding program.
"Having species like the white stork here at the centre reminds us of what we stand to lose if we don't act now and stand up for the protection of precious habitats," John Arbon, the living collections manager, told the BBC.
