Boom sound of the rare bittern heard across Tanners Point

A bittern recently photographed at Kaituna wetland. Photo / Mathew Herring

Tanner’s Point residents may be hearing a new sound echoing across the peninsular - a deep, low-pitched ‘’boom’' at dawn or dusk.

That booming sound — which could be likened to blowing across the top of a jug — is the sound of the extremely rare bittern bird.

Tanners Point Pest Free Project members are ‘’thrilled to bits’' to hear the unique sound of the bitter, which hasn’t been heard in the area for about 20 years.

Coordinator Heather Wills says the group, along with other pest-free groups working close by, has ramped up pest control efforts in the past 20 years, which has seen the return of many birds. Besides the bitterns, a number of birds are nesting now, including banded rail. Ducks, pheasant and quail nest on the ground with fernbirds in tall rushes, grasses or low shrubbery.

Wills suspects there are up to two pairs of bitterns making themselves heard. Bitterns have also been seen in Maketu.

Bitterns are rarely seen due to their secretive behaviour, their colouring and habitat. It is estimated there are fewer than 1000 in New Zealand.

So it’s important the birds are protected, Wills says.

‘’We have been working now for many years and we’d be heartbroken if these birds were accidentally shot or killed by a roaming dog.

‘’Owing to their habit of freezing in place when they sense danger, bitterns are very vulnerable to disturbance or attack by dogs and pest animals such as ferrets, stoats and weasels.

‘’Please keep your dogs on leads if you are walking around the esplanade or on the mudflats.’’

If the birds are disturbed they are likely to abandon their nest, or if the foliage is disturbed and exposes their site — air hawks will spot an easy meal, Wills says.

Department of Conservation senior ranger Karl McCarthy says low numbers of the birds will be using a complex of wetlands around the area.

‘’The Tauranga harbour margins are fantastic bittern habitat.

‘’Predator-free groups are doing a great job keeping predator numbers down around the area. Bittern are particularly vulnerable over the nesting season October to December and then their chicks are vulnerable after that.

‘’Both cats and dogs have caused nesting failure for bittern, so it’s best to keep them out of their habitat altogether.’’

Bittern are protected wildlife and anyone caught harming one could be prosecuted under the Wildlife Act.