Where and when to see and hear bitterns booming in Dorset

Listen for booming male bitterns this month as the UK’s loudest bird is hiding in the reedbeds of the RSPB Weymouth Wetlands Nature Reserves 

Setting your alarm for 3am on a weekend morning in March might not be everybody’s idea of fun. However, for our Weymouth wildlife surveyors, the anticipation of what they might encounter is enough to get them bouncing out of bed and this early hour and heading off to RSPB Weymouth Wetlands Nature Reserves, armed with a flask of coffee and a torch. 

The bird they are hoping to hear, rather than see, is the UK’s loudest bird, the male bittern. A member of the heron family, this shy bird has a short, thick neck which contains powerful muscles enabling it to emit a sound that can travel around 2km. This boom, as it is commonly known, is one of the most eerie sounds of the wetlands. Imagine the noise you get when you blow across the top of an empty bottle amplified and projected across the reedbeds. That is the boom of a bittern and it’s quite unique. The male bittern uses this boom to define his territory and potentially entice a mate.  

Adult bittern moving through a reedbed their plumage colouring makes them hard to spot (Image: Ben Andrew (rspb-images.com))

Reed clearance, drainage of wetlands, and hunting during the 19th century led to the extinction of bitterns as breeding birds in the UK. In the mid-20th century, they gradually began to return with 80 booming males recorded in 1954, but numbers plummeted once again with just 11 males by 1997. The RSPB led a research project, in partnership with Natural England (formerly English Nature), to define the needs of bitterns, this lead to recommendations about how the wild habitats they flourish in, mainly wetland reedbeds, should be managed. The RSPB and other conservation bodies continue to restore and manage reedbeds for the benefit of bitterns and other wildlife. As a result, in 2021 UK Bittern Count recorded over 220 booming males. If you build it how they like it, they will come! 

Bitterns are a little smaller that a grey heron and have a thick powerful neck that helps them to make their booming call (Image: Andy Hay (rspb-images.com))

The RSPB has carried out extensive restoration works at Weymouth Wetlands creating a mosaic of ditches, reedbed and shallow vegetated edges, all characteristics that the bitterns require to make their home here. We are hopeful that the bittern will soon be breeding successfully at Weymouth. Find out more at rspb.org.uk/radipolelake 

When spooked a bittern with stretch its neck upwards so it looks like a reed in the reedbed, making it harder to spot (Image: Ben Andrew (rspb-images.com))

Bittern spotting: Despite its size (slightly smaller than a grey heron) this secretive bird moves silently through the reedbeds. It’s hard to spot because the dark brown streaks on its pale, buff brown plumage offers perfect camouflage enabling it to remain almost invisible amongst the reeds. When the bird is spooked it freezes with head and beak pointing straight up towards the sky, even swaying slightly so that it appears to become part of the reedbed. 

Although the male bittern will boom at any time of the day or night, your best chance of hearing it will be at dawn or dusk in early spring. Plan a trip to RSPB Weymouth Wetlands and you might be lucky enough to hear this memorable call. Listen to the booming bittern ahead of your visit at bit.ly/RSPBBittern. 

RSPB Weymouth Wetlands is the ideal habitat for bitterns to breed in (Image: Ben Andrew (rspb-images.com))

Even if the bittern doesn’t boom for you, visitors can still soak up the special sights and sounds of the reserve wildlife in the early morning light, enjoy warblers singing in the hedgerows and maybe even spot a deer or otter. 

Hyde’s Heath at RSPB Arne is a great place to see and hear woodlarks in spring (Image: Ben Andrew (rspb-images.com))

At RSPB Arne, near Wareham, woodlarks will be active this month, singing to mark their territories and attract a mate. Hyde’s Heath at RSPB Arne is a great place to encounter these ground nesting birds with their beautiful song. Woodlarks favour fresh areas of bare ground, clearings, and sparse vegetation. Hyde’s Heath is a recently felled forestry plantation where the RSPB are restoring vital heathland which already supports good numbers of breeding woodlark. Find out more at rspb.org.uk/arne 

RSPB Radipole offers the ideal reedbed habitat for bitterns (Image: Andy Hay (rspb-images.com))

Hire a Guide: Experience an exclusive visit to RSPB Arne or RSPB Radipole and Lodmoor nature reserves with our special Hire A Guide experiences. This bespoke service offers up to six guests the opportunity to explore the nature reserves with a knowledgeable guide for up to three hours. Tours can be tailored to your interests and go at a pace that suits you, so are ideal for families, small groups, wheelchair users/people with limited mobility (you can hire a Tramper in advance). Prices are from £88 for RSPB members or £110 for non-members, plus 50p booking fee. Once purchased, Hire A Guide tickets are valid for one year. Find details at events.rspb.org.uk/arne or events.rspb.org.uk/radipolelake 

Lesley Gorman is an RSPB Visitor Operations Manager based in Dorset