Increase in Kererū, piwakawaka, and tūī - garden bird survey

Twitchers are recording more kererū, pīwakawaka, and tūī in their backyards each year, according to the garden bird survey.

Manaaki Whenua landcare research has been co-ordinating the mid-winter citizen science project for 16 years.

It was now noting longer-term trends, such as population growth slowing.

Tūī counts increased 266 percent in the last decade but that slowed to just a 25 percent increase over the last five years.

Over ten years, kererū counts show a moderate 83 percent increase and an increase of 10 percent over five years.

There were 55 percent more pīwakawaka over 10 years compared to the shallow increase seen in recent years.

Meanwhile, korimako (bellbird) numbers have fallen more than a quarter in several regions.

Survey co-ordinator Dr Angela Brandt told Morning Report every participant spends an hour in their garden each day during the survey and records the maximum number of each species they hear or see.

Since 2012, bird counts have been gathered from almost 44,000 garden surveys.

Nothing was causing particular alarm this year, Brandt said.

In a few regions there were shallow to moderate declines in the short term for tauhou (silvereyes), korimako in the North Island and some introduced species, she said.

"It's something to keep an eye on but we know people are doing lots of work to improve things for birds with predator-free initiatives and restoration initiatives."

Participants recommended managing weeds and predators, making sure bird food wasn't accessible to predators and creating habits for birds to feed and nest.

This year's survey runs from 24 June to 2 July.