Female (left) and male (right) kākā at a ZEALANDIA feeding station.
Male and female kākā are difficult to differentiate. Males tend to be larger with a bigger mandible and rounder head. Females tend to be smaller and may have a prominent yellow eye ring during breeding. Unless their sex has been noted from their breeding behaviour, this large degree of overlap means that genetic testing is usually necessary to be sure.
Males give a soft “tsee-tsee-tsee” call during courting and when showing females potential nest sites.
Judi Lapsley Miller, C-C 4.0