Rare wading birds counted at record numbers in Christchurch estuary

One of the world's rarest wading birds has been counted at record numbers at a Christchurch estuary.

The Tōrea pango, or variable oystercatcher, have been booming in population at Avon-Heathcote Estuary/Ihutai.

Christchurch City Council ecologist Andrew Crossland counted 232 birds wintering at the Avon-Heathcote, beating the previous record of 218 birds counted about 14 years ago.

"The Avon-Heathcote has already been identified as one of the top 15 sites nationally for this species, but if more than 200 birds wintering there becomes a regular thing, then it would be one of the top five or so - a pretty cool result for our little estuary," he said.

The Tōrea pango is endemic to New Zealand, and has a national population of 5000-6000.

The Christchurch population of the shorebird has been steadily expanding in the last few years, but has been closely monitered for some time, Crossland said.

"It's a species for which we have a very long monitoring data set going back to the 1940s, and annually since 1985 and is one of the 'indicator species' we use to track biodiversity trends."

The bird is present around most coastal areas of New Zealand, and is most abundant in Northland and in Tasman and Golden Bay.

While predator control was the cause of increasing in some areas of the country through predator controls, those measures weren't in place in Canterbury, Crossland said.