A bellbird survey will be undertaken in September or October by Landcare Research in Hamilton, as part of the Halo project.
Hamilton residents are being encouraged to keep reporting sightings of tui and bellbirds as the project enters its fifth year.
For tui, Halo involves pest control at selected breeding sites around Hamilton to help improve the chances of nesting success and of tui becoming more established in the city. It is also expected other urban areas, such as Cambridge, will benefit.
In winter, adult tui traditionally visit Hamilton from their breeding sites outside the city to feed, so sightings between May and August help gauge how big an effect Halo is having on the tui population.
Researchers are aware that as people became used to tui in Hamilton, they may not be as motivated to report them.