BOOM!

Early this morning, an eery noise emanated from the depths of a reedbed on Holywell Lake...the sound of a booming bittern!

Booming is the noise this enigmatic species of heron makes to try and attract a female in spring. It's a bit like a foghorn, or what you get when you blow across the top of a big empty plastic bottle. It's impressively loud, too, audible up to several miles away.

Hearing one this morning was music to our ears because bitterns are one of the UK's rarest breeding birds; their very small population and dependence on reedbeds puts them on the UK Red List (species of top conservation concern).

The Fens was a bittern stronghold in the past, before extensive drainage took place, so there's something particularly special about hearing that strange cry floating across the water here again...

Image: a well-camoflagued bittern at Fen Drayton Lakes, photographed earlier in the year by Peter Moule

What happened? Back in the Middle Ages bitterns were common enough to be a popular dish. Records from banquets show them being served up in their hundreds up until widespread draining of the UK's wetlands combined with hunting to devaste the population. The bird tentatively recolonised in the early 1900s, only to suffer a more recent slump to just 11 booming males at seven sites in 1997. This had conservationists, many RSPB staff and volunteers, working harder than ever to save them as a breeding species.

Thanks to significant discoveries about these birds and their habitat requirements, and bold action in response, we've held onto this tiny population and brought it back from the brink.

Key reedbeds across the UK were swiftly enhanced with bitterns' needs in mind, and several ambitious reedbed creation projects were launched to secure their long-term future. RSPB Lakenheath Fen (formerly carrot fields) and the Hanson-RSPB Wetland Project (restoring a working sand and gravel quarry bit by bit) are two very local examples of headline projects.

In 2009, only about a decade after that low point, there were 11 booming bitterns in Cambridgeshire alone. Fantastic!

Here at Fen Drayton we're doing our bit too, with bitterns booming each spring for most if not all of the last five years. Fingers crossed for some successful nesting on the reserve now...