Results from the 2023 State of New Zealand Garden Birds / Te Āhua o ngā Manu o te Kāri Aotearoa survey show a 210 per cent increase in the regional long-term trend in tui sightings in the region.
Across the rest of the country, tui numbers show only a shallow increase over 10 years, and little to no change over the previous five years.
That’s nothing to worry about, says Manaaki Whenua – Landcare Research senior researcher Dr Angela Brandt.
“The rate of these increases is generally slowing down, which makes some sense when you think about how percentage increases work. Having four tui sightings is a 100 per cent increase when you started with only two sightings, but seeing six the next year becomes a 50 per cent increase.”
There has also been a rapid increase in the region of both kererū and pīwakawaka (fantail) over the past 10 years, with shallow increases nationally.
However, Brandt says there is not such good news for silvereye whose long-term shallow decline nationally has shifted to a moderate decline in the short term. Goldfinch and chaffinch counts are showing a rapid decline (30 per cent for both species) over five years.
Brandt says being able to notice this trend proves the value of the NZ Garden Bird Survey.
“Birds are important indicators of the health of New Zealand’s environment, and many perform important ecosystem functions. . . If we see birds begin to decline that suggests something has changed in their habitat, perhaps an increase in predators or a decrease in available food and shelter, which could also be affecting other species,” she said.
Garden bird survey founder Eric Spurr said he was excited his vision to provide long-term data on New Zealand garden bird trends, when establishing the survey 18 years ago, is now bearing fruit.
He was also thrilled at the number of people volunteering to take part in the survey over the years.
“Without these volunteers – more than 60,000 since the survey’s inception – none of this data would have been collected,” he said.
- The 2024 survey runs from June 29 – July 7. For bird identification information, visit https://gardenbirdsurvey.nz/
