18 Feb 2022

Big increase in kererū and pīwakawaka seen in New Zealand gardens - survey

7:24 pm on 18 February 2022

New research shows there are significantly more kererū and pīwakawaka in our backyards than there were 10 years ago.

Kereru

The survey results show that kererū counts increased by 102 percent over 10 years. Photo: CC BY-SA 2.0 Duncan / Flickr

The findings come from the New Zealand Garden Bird survey by Manaaki Whenua - Landcare Research, which is the country's longest running citizen science project.

Last July as part of its annual survey, almost 15,000 people counted the number of birds they could see in gardens, parks and school grounds.

The results show that kererū counts have more than doubled, increasing by 102 percent over 10 years, while pīwakawaka counts were up 47 percent over the same timeframe.

Piwakawaka or fantail are common in gardens around New Zealand.

The number of pīwakawaka reported in the survey increased by 47 percent over 10 years. Photo: CC BY-NC 2.0 Daniel Pietzsch/Flickr

There are also more tuī in Canterbury, Marlborough, Otago, and the West Coast with their numbers across the country growing by 30 percent.

The decline of silvereye (tauhou) is lessening, with a moderate increase in numbers since 2016. But starling numbers have been falling for the last 10 years, although the rate of decline slowed this year compared to last.

Other birds including song thrush, house sparrows, dunnock, chaffinch, and korimako (bellbirds) show little change over the past five years.

Nationally, the number of myna birds has shown little change except for in Wellington, where they have quadrupled since 2010.

The results are put through computer analysis which takes into account of whether birds are fed in each garden, how many gardens there are in each region of New Zealand and whether it is in a rural or urban setting.

Founder Dr Eric Spurr said the  results were encouraging and showed the value of long-term citizen science monitoring. 

"The survey does not attempt to determine the causes of changes in bird counts, but it is tempting to suggest that the increases in counts of native birds reflect the results of increased predator control and habitat restoration activities around the country."

Manaaki Whenua researcher Dr Angela Brandt said the data helped scientists understand how bird populations are changing across New Zealand.

"What's exciting about having so many years of surveys now is that we can see how trends are changing over time. Some species show an uptick - like kererū - or a lessening decline - like tauhou - compared with earlier reports. Importantly, because the survey is done every year, we could have an early warning if a species started to decline."

This year the survey runs from 25 June - 3 July. Information about bird identification can be found on the NZ Garden Bird Survey website.

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