Ecology, Behavior, and Conservation of the Maui Parrotbill

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Abstract
The distribution, habitat response, sexual dimorphism, foraging, breeding, and flocking behavior of Maui Parrotbills (Pseudonestor xanthophrys) were studied over a five year period. The species'' present range is confined to montane rainforest on eastern Maui [Hawaii, USA] but dry lowland habitats on Maui and Molokai were occupied before Polynesian contact. Birds occurred from 1,250 to 2,150 m elevation, becoming most abundant at 1,750 to 2,000 m. In Kipahulu Valley, birds moved to lower elevations in some seasons. Maui Parrotbills associated with areas where vegetation was less disturbed from feral pig activity. Activity areas had more developed understories and more open canopies than nonactivity areas. Birds tended to forage in the subcanopy and understory, with 66% of the prey captured 1 to 5 m above ground. Plant species use deviated from expectations based on availability. The most frequent means of prey capture was excavation for timber-boring insects in dead branches on live plants. Foraging accounted for 39% of the diurnal time budget; an average prey item appeared to account for 1% of the daily energy intake. Male birds had longer, more deeply hooked bills than females, and tended to excavate to greater depths. Sexes differed in tree species use and foraging maneuvers, but not in substrate use or foraging height. The principal limiting factors appeared to be habitat loss, avian disease, habitat degradation, predation, and competition from exotic species. Control of pig populations is a needed management action.