The puaiohi, and other native Hawaiian birds, face a range of threats including disease, introduced predators and competitors, habitat damage, forest clearance and human population growth (5). Many of these threats interlink making the problems harder to resolve.
Feral pigs on the island damage the lower layers of the forest as they move through it and dig for food (2), and also create wallows of mud which provide a breeding site for mosquitoes, the main vector of introduced diseases (3). Mosquito-carried diseases, and forest clearance by humans, are responsible for driving the birds from its lowland habitat into upland areas where there are fewer mosquitos (3). Fortunately, there is some evidence that certain puaiohis are developing resistance to avian malaria, one of the mosquito-borne diseases, so this disease may cause less mortality in the future if the resistance spreads (6).
Rats pose another problem as they raid birds nests and compete for food, and invasive plants threaten to replace the plants that the puaiohi relies on for both food and shelter (2). Thankfully, hurricanes have not threatened the puaiohi as much as many other native Hawaiian birds because its ravine habitat is relatively sheltered (4).