Boom: Beware Bitterns breeding!

A local resident told me recently she’d spotted a Bittern on one Strathnaver wetland, one of 3 areas in Strathnaver where the very rare Bitterns are known to breed locally.

Bittern breeding season falls between August and May. They lay between 3 and 6 eggs sometime between August and December. The eggs hatch after about 25 days and then fledging is complete after another 49 days or so.

Dog owners: please don’t let your dogs loose in or around the Strathnaver ponds and lakes.

While you may not see a Bittern you may hear its mating call around dawn or dusk. Australasian Bittern Survey (Birdlife Australia) tells us:

Very soon, male Australasian Bitterns will begin establishing their territories in freshwater habitats comprising dense reedbeds, and producing a distinct, low frequency call referred to as a ‘boom’. This boom both attracts females and intimidates rivals.

Further — Keep An ear Out For Australasian Bitterns At Your Local Wetland — Birdlife Action Network:

The best way to find a bittern is to listen for their booming calls during the breeding season. Male bitterns have a distinct, low booming call likened to a foghorn that they repeat several times in succession, calling most frequently at dawn and dusk during the spring summer.

New Zealand Birds Online fills in more detail — Australasian bittern | Matuku-hūrepo

Voice: male bitterns produce a sequence of distinctive ‘wooom’ calls known as ‘booms’. Each call sequence consists of several individual booms, ranging from 1-10 booms per sequence, with a mean of 3. These sequences are repeated at regular intervals that appear consistent to individual birds.

While I haven’t yet been lucky enough to spot a Bittern myself, I did hear its call one night a year or two back. What a treat!