If a bird can be said to skulk, then the bittern skulks. It hides away in reedbeds, peering out of the rushes before placing its long legs in measured, slow, and careful steps, its amber and brown plumage protecting it against detection - blink, and you’ll miss it.
How to count bitterns
This is why researchers tend to listen for this elusive member of the heron family instead, waiting by likely wetland habitats to hear a tell-tale, foghorn-esque ‘boom’. In the breeding season these booms, i.e. song, from males can sometimes be heard miles away (it’s what makes the bittern the loudest bird in the UK). Without it, the task of counting these elusive birds would be… tricky.
A bittern skulking amongst the reedbed (c) Ben Andrew (rspb-images.com)
Bringing a species back from the dead
But why would we want to count bitterns in the first place? The answer is, simply and sadly, that at one point there were no bitterns left to count.
Once bitterns lived across the UK, giving rise to such gloriously colourful local names as bog blutter, buttle, bumbagus, myre-dromble, miredrum, bog-bluiter and butterbump. But around 1885 their calls fell silent, driven out by a combination of over-hunting and draining of their wetland homes. Traditional management of reeds once created good breeding sites for bitterns, but as demand for reed declined many reedbeds fell into neglect or were drained for other farming, leaving the bittern fewer and fewer places to raise their chicks.
This meant that even when bitterns were seen to be breeding again in 1911 in the Norfolk Broads their populations still struggled to recover. Bitterns haven’t reached Scotland or Ireland since, and while there was a peak of 80 booming males counted in the 1950s, by 1997 they were on the brink of extinction once more with only 11 soulful calling males heard across the entire UK.
Why rewet wetlands?
Concerted conservation efforts including the restoration, recreation, and protection of wetlands have helped bitterns to inch their way back up, and over the past few decades there’s been a strong increase.
Just last year a record 228 booming males counted in England and Wales, with over half on RSPB reserves! This is up from 209 in 2019, which itself was an increase from 189 in 2018 (monitoring in 2020 was interrupted by the coronavirus pandemic).
Booming was also reported from eight entirely new sites in 2021, which is great news for the bittern – to fully recover they cannot just cling on in pockets of protected habitat. Wetlands must be refreshed and recovered all around the UK.
Increasing healthy wetland habitats is also good news for people. Wet meadows, reedbeds, lakes and ponds, they’re all great at absorbing excess water which helps to prevent flooding of homes and businesses. They’re also excellent carbon sponges. In fact, worldwide, coastal wetlands absorb more carbon than all the trees put together. And as well as the bittern and other birds, wetlands are home to everything from dragonflies to water voles to fish.
If you hear a booming bittern, you know you’re in a special place that’s also helping protect people against floods and the climate crisis, as well as creating a sanctuary for declining wildlife. No wonder the foghorn call gives people goosebumps.
Where to see bitterns for yourself
For a chance to hear booming yourself, head to one of the reserves across England and Wales:
Although bitterns do boom at any time of the day, the best times to hear them are in the two hours around dawn and at dusk, especially about half an hour before sunrise.
Select reserves are also holding special bittern-themed events, so head to www.events.rspb.org.uk to find one near you – just make sure to keep your ears, as well as your eyes, peeled.
Thank you to our bittern survey volunteers
Volunteers are an essential part of our surveys, working up and down the countries and often coordinating surveys to ensure a whole site is covered from different points at the same time. Without them, and the welcoming landowners and dedicated conservation site staff, a full national survey would not be possible. We want to say a huge thank you to everyone who helps to make it happen!
Notes
Data have been collated from a number of sources, including BirdTrack (which is organised by the BTO for the BTO, RSPB, BirdWatch Ireland, Scottish Ornithologists' Club and Welsh Ornithological Society) and eBird (eBird Basic Dataset. Version: EBD_relAug-2021. Cornell Lab of Ornithology, Ithaca, New York. Aug 2021).
The RSPB coordinates monitoring and collates records each year, through the Bittern Monitoring Programme, an Action for Birds in England (AfBiE) project, a conservation partnership between Natural England and RSPB.
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