First recorded booming within the DU Wairio wetland

The spring 2022 survey report compiled by Shane Cotter, a contractor engaged by GWRC.

John Cheyne of Wetlands Works led annual spring surveys for Australasian bittern (matuku, Botaurus poiciloptilus) and spotless crake (pūweto, Zapornia tabuensis) at selected wetlands within Wairarapa Moana between 2012 and 2021. In 2022, John passed this responsibility to me. I conducted the annual spring (October-November) 2022 survey using the same methodology as in previous years so continued comparisons could be made of the annual results.

This year’s survey focused on the core wetlands (Boggy Pond, Matthew’s Lagoon and Wairio wetland) and the northern wetlands (Barton’s Lagoon, Tauherenikau delta, Simmond’s Lagoon, JK Donald Block). Only booming male matuku are surveyed because females are much less vocal and therefore very difficult to detect and monitor. This booming call is associated with males attempting to attract females for breeding. Pūweto were also surveyed at Boggy Pond and Matthew’s Lagoon.

In the 2022 survey, 11 booming male matuku were located at the core wetlands and 12 in the northern wetlands. This is an increase in previous years and a record number at both locations. At the core wetlands, numbers have remained relatively stable at 8-9 birds since 2014 while at the northern wetlands, annual numbers of male matuku has varied between 3-9 birds. Overall, the combined number of booming male matuku at the core and northern wetlands has steadily increased from 10 in 2016, to 16 in 2018, to 18 in 2020, and now 23 birds in 2022. In addition to the 23 male matuku heard booming during the 2022 survey, three other birds were seen, one in Matthew’s Lagoon near Boggy Pond and two in Wairio wetland.

At Boggy Pond, nine pūweto were located, the most in Boggy Pond since 2018 and significantly up on the single individual in 2021. At Matthew’s Lagoon, none were recorded during the kayak survey which has been a regular result there since 2014. While undertaking the matuku survey, four other pūweto were heard calling independently, not in response to playback calls. Two were calling in Matthew’s Lagoon close to each other while at two locations within Wairio wetland, one individual was heard calling. I believe there are more pūweto present than recorded during the pūweto surveys. They have just moved to different areas of the wetland complex outside the pūweto survey routes seeking more suitable habitat.

On-going predator trapping with the regular servicing of traps is essential as several predators were seen dead in traps within days of the traps being serviced and rebaited with fresh bait by the trapping contractor at the core wetlands. These included a weasel and several rats. All traps observed were well set up and maintained, and had good vegetation clearance.

Follow the 'read more' link to view the survey report.