This Pacific island reed warbler was studied on Kiritimati, where it was more often found in places with taller Heliotropium and Scaevola plants.
Across the three island populations compared in the paper, Kiritimati birds tended to be smaller than birds from Washington and Fanning Islands. Male wings were longer on average, although the ranges overlapped; the study found no consistent island-to-island plumage difference.
In the Kiritimati survey, birds were more common where Heliotropium and Scaevola plants grew taller. Recorded nests were in forks of Heliotropium trees just below the crown.
An extinction-risk assessment has not been added yet.