Although there have been no full-time Bittern monitoring field staff since 2011, it was again encouraging to see the excellent coverage of sites across the country. Many thanks to all the volunteers, conservation site staff and landowners who were able to monitor sites in 2022.
In 2022 the same number of booming males were recorded as in 2021. A minimum of 228 boomers were recorded at 103 sites. On RSPB reserves, 119 confirmed boomers were recorded, from 39 sites.
Bittern adult in Essex (c) Ben Andrew (rspb-images.com)
The minimum number of booming male Bitterns (in red) in the UK and the number of occupied sites (in blue) between 1990 and 2022.
Bitterns are dependent on reedbed habitats as they move through them at the water's edge, seeking out fish, insects, and amphibians to eat. They are the loudest bird in the UK - the males make a remarkable far-carrying booming sound in spring which can be heard three miles away and is used to establish territories and attract female mates through the season. Bitterns are well-camouflaged so the most reliable way to count them in the breeding season is to listen for this song.
Bitterns in the UK
From historical sources, it is clear that Bitterns once bred across the UK, giving rise to such colourful local names as bog blutter, buttle, bumbagus, myre-dromble, miredrum, bog-bluiter and butterbump. By the 1880s, however, they were considered extinct as a breeding species in the UK.
Following recolonisation early in the 20th Century, initially in the Norfolk Broads, numbers increased to a peak of about 80 booming males in the 1950s, with most in the Broads. There then followed a steady decline, leading to a programme of monitoring and research to determine accurately the number of individuals at the few sites that still retained Bitterns in the 1980s and to help diagnose the causes of decline and to identify a means of halting and then reversing it.
Conservation success
The species returned to Norfolk in 1900 but dropped again to just 11 booming males by 1997, leaving them on the edge of a second national extinction. A research programme by the RSPB, investigated the needs of the birds. A key part of bringing Bittern numbers back up was recreating, managing and protecting their wetland habitats.
Major wetland habitat management, habitat restoration and creation are ongoing for this species and annual population monitoring is the main yardstick with which we can measure its success. Some of the best places to see and hear bitterns now are wetlands that were created, from the mid-1990s, for Bitterns and other wetland wildlife.
Habitat management, restoration and creation has taken place at more than 80 reedbeds throughout the UK since the mid-1990s, and many of these sites are away from the traditional core East Anglia breeding areas, to encourage Bitterns to reoccupy their former range and give the species a sustainable long-term future in the UK.
The second EU Life project, from 2002 to 2006, was the first and largest project of its kind in the UK aimed at safeguarding a species’ habitat in the face of imminent changes due to climate change, as most of the UK in the 1990s were all along the East Anglian coastline, where many sites are highly vulnerable to sea water inundation during storms, which climate-change models predict will increase in severity and frequency as our climate changes.
Last year’s breeding Bitterns
Although the same number of males were counted in last year’s survey, the population is booming. Over half of the UK’s Bittern population can be found on RSPB reserves, with some managed predominantly for their reedbeds to attract rare wetland birds such as Bittern, Crane and Great White Egret.
RSPB Salthome, on Teesside, is one of these sites and its conservation efforts were rewarded with its first breeding success last year, making it the most northern record so far in its recent history. Although most of the records are in England, with a few in Wales, Bittern were once found breeding in Scotland and Northern Ireland, and there is hope that they will once again find themselves there.
Although Bitterns are still a rare bird, there are some great places to experience them first-hand:
The RSPB helps to coordinate Bittern monitoring across the country each year and collates breeding season records, through the Bittern Monitoring Programme, an Action for Birds in England (AfBiE) project.
Can you help?
In 2023, we would request that the many volunteers, conservation site staff and landowners continue to monitor sites for booming males and nesting attempts as has happened this year. Given the increasing number of successful nests reported across the country, it is increasingly likely that new and formerly-occupied sites will become occupied by booming Bitterns in the near future.
The RSPB will aim to collate all the records, with the intention of producing a similar report next year. To report any observations this season, or to request a copy of the survey methods and recording forms, please Simon Wotton.
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