Bird counts: Important for conservation, and not always a walk in the park

Tuesday, 5 January 2021

Contractor Nikki McArthur undertakes the official Wellington bird count each year, a joint project by the Wellington City Council and the Greater Wellington Regional Council, used to determine trends in bird populations around the city.

In all his years of bird-counting duties, Nikki McArthur has been interrupted by some strange things.

One year at Polhill Reserve, his five minutes in the field were punctuated by someone’s saxophone practise, and in 2018, the departure of Prince Harry and Meghan Markle in a military helicopter cut through the peaceful chirping of birds.

McArthur has been officially contracted to the bird count, a joint project by the Wellington City Council and the Greater Wellington Regional Council, for the past six years.

The bird count does what it says on the tin: McArthur has a series of locations to visit, where he stands for five minutes and records every bird he sees or hears.

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Contractor Nikki McArthur undertakes the official Wellington bird count each year, standing in various spots around the city and noting every bird he sees or hears.

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The departure of Meghan Markle and Prince Harry interrupted one of McArthur’s bird counts in 2018.

The data is then compiled into a report – released early the following year – which informs experts on the effect predator eradication and conservation efforts are having, and which locations and species need more attention.

There are 100 locations around the city, all in council parks and reserves. Two contractors split the task, usually getting around 50 each.

It takes McArthur about two weeks to get around all his stations, sometimes down steep slopes and deep into bush.

It is important the conditions year-to-year remain constant, such as the weather, the time of year, and the time of day.

The number of Whiteheads, reintroduced to Zealandia in the 2000s, is on the rise, but the little birds are still hesitant to venture too far from the safety of the predator-free fence.

Where that isn’t possible, McArthur take notes that will inform the data. His note on the day of the royal interruption read: “Royals in helicopter, off to winery.”

The perfect day is calm, no rain, minimal unusual sounds, around the end of November or early December.

Ninety per cent of detections are heard, not seen, so it is important for the counters to be well versed in birds’ appearance and sounds.

The count is used to determine trends in bird populations around the city.

This is different to the Great Kererū Count, in which volunteers with minimal experience are relied on for data.

There has been a steady increase of tūī, kaka, kākāriki, tiaki and kererū.

For Henk Louw, biosecurity specialist at Wellington City Council, the best part is seeing birds thriving in areas where conservation work is carried out.

Some species are more puzzling. Whiteheads were reintroduced to Zealandia in the 2000s, but since then they have only been detected within a few 100 metres of the boundary fence.

“It’s weird considering they’re highly mobile. They haven’t spread as they should,” McArthur said. Perhaps more work was needed to make destinations further afield attractive for them.

The long-tailed cuckoo is another strange case, only spending the summer in New Zealand, returning in January to North Australia and the Pacific.

Like other cuckoos, they lay their eggs in others’ nests, in particular, those of whiteheads.

When the whiteheads died out, the cuckoos stopped visiting, as there was nowhere to lay their eggs.

It would take a while for nature to adjust. The cuckoos were still under the impression they wouldn’t find homes for their eggs so, despite the reemergence of whiteheads, cuckoos were still largely absent from the tally.

According to city council biosecurity specialist Henk Louw, native bird numbers had been increasing across the board thanks to the predator free efforts in key areas; Otari-Wilton's Bush, Polhill Reserve, Wrights Hill, and Khandallah Park.

There were more than 30 conservation and predator eradication groups around the city. “And what was done years ago influences the numbers today.”

Zealandia was the “mother ship”, with most birds spotted in the area directly around the predator free fence.

“For me, [the best part is] seeing the birds moving outside the fence and doing well,” Louw said.