This story was originally published by RNZ.

The country’s longest running citizen science project, the New Zealand Garden Bird Survey, started Saturday.

People are being encouraged to head out into their gardens over the next nine days to spend an hour counting all the birds they see and hear.

The survey helps scientists understand the health of garden bird populations and the wider environment.

Manaaki Whenua researcher, Angela Brandt, said it provides a snapshot into how bird populations are changing across New Zealand.

“What’s exciting about having so many years of surveys now is we can see how trends are changing over time.

“Some species show an uptick – like pīwakawaka, or a lessening decline – like tauhou – compared with earlier reports. Importantly, because the survey is done every year, it gives us an early warning if a species starts to decline.”

The survey’s founder, Eric Spurr, said more and more people take part every year.

“The results show the value of long-term citizen science monitoring, and while the survey does not attempt to determine the causes of changes in bird counts, it is tempting to think increases in counts of native birds reflect the results of increased predator control and habitat restoration activities around the country.”