[5] The male's song often starts with a series of three squeaks and builds into a distinctive long plaintive wavering trill that rises and falls.

[5] However, they have been seen to occasionally eat fruits, perhaps to make up for limiting nutrients that are low in invertebrates, or due to their very high energy method of feeding.

[5] In terms of mating behaviours, males sing all year around, and this identifies the sex of the warbler as there is no clear sexual dimorphism in the species aside from size.

[7] This is perhaps an effort to increase the strength of the pair bond and synchronise with their partners behaviour, as the display occurs throughout all stages of breeding, especially when the female is present.

[7] Grey warblers are unique among New Zealand birds in building a pear-shaped nest with a side entrance near the top.

[7] Laying of eggs occurs over 15-16 weeks of the year, and the first clutch is laid at different times during a 6-week period.

[5] Over the whole laying period, the grey warbler only produces two clutches at a slow rate over the long breeding season.

[10] In avian species, begging behaviour is very common in young hatchlings, to capture the attention of a parent bird to gain access to more food.

For instance, the adult grey warbler uses specific behaviours to reduce the predation pressure of the hatchlings' begging.

[11] Studies highlighted that as a chick became hungrier, call structure narrowed in frequency range, while decreasing in amplitude.

[5] For the cuckoo hatchling to survive and be successful, it needs to identically mimic the grey warbler chicks begging behaviour.

[15] Warbler males also spend a significant amount of time mate guarding; for instance, when the female is gathering materials to build the nest.

[16] In each situation, the adult grey warbler would chase the young rifleman silently, while the riflemen would be producing frantic distress calls to their parents.

[16] These chases would vary in length of time and would usually result in the parent rifleman producing an alarm call that would ward off the warbler.

[16] Aggressive behaviour like this may result in niche displacement of the young rifleman, which would benefit the warbler as it would give them more access to important resource.

Therefore, it can be understood that there are several reasons for why an adult warbler would perform this behaviour, for instance, to defend resources within its territory, or competition for food.

The direction in which a grey warbler would build its nest served as an indicator of forthcoming weather conditions to Māori – in this respect, the bird was known as a manu tohu tau.

[17] The tradition states that a grey warbler will build the nest entrance in the opposite direction to the prevailing wind.