Where to see bittern in the UK

How to find bittern

Most people who go looking for a bittern don't see one. Worth knowing before you set out, because the disappointment is easier to take if you were expecting it.

The bird is a heron that has spent a few million years learning to look like a reed, and it is very good at it. A bittern standing two metres away with its bill pointed at the sky is reliably invisible, and it will stay that way for as long as it thinks you're watching.

So most encounters are auditory. From late February the males boom — a low note, more like someone blowing across the neck of an empty bottle than birdsong, pitched deep enough that you feel it a moment before you place it. It carries three miles over still water. On a calm March morning at Ham Wall you will almost certainly hear one: the occurrence records show 1,233 spring sightings within five kilometres against 202 in winter.

That gap is about detection, not birds. Bitterns are there all year. In spring they announce themselves; the rest of the time they don't.

Which sets up the choice. Go in spring and you'll hear a bittern and probably not see one. Go in a hard freeze, when ice pushes them out of the reeds to fish the open margins, and the odds of actually watching one flip completely. Cold snaps are the tip-off — the colder the better, and the first two hours of light are worth more than the rest of the day put together.

Two practical things. Pick the hide overlooking open water at a reed edge rather than the one with the widest view, because bitterns work the channels. And a bird crossing between reed stands gives you about four seconds, so have the binoculars up before you need them.