These cute little birds are native to Hawaii and are mostly confined to limited terrain. They are also very vulnerable to invasive species, increases in human population, and new diseases. With climate change becoming more of an issue, this could lead to a greater decline in these birds.
The Hawaiian Honeycreepers live in higher elevations in trees where their habitat is less likely to be destroyed by humans. Higher elevations are cooler and also have less mosquitoes, giving them a lower chance of contracting avian malaria (which they are very susceptible to). As the world continues to warm, mosquitoes move into higher elevations, and therefore the honeycreepers have nowhere to escape and are more likely to contract a mosquito-borne illness. At one time, the Hawaiian Islands had no mosquitoes and no mosquito-borne diseases until about the 1800's. A scientific study noted that avian malaria has doubled since the 1990's in the upper regions of Kauai. People who have worked in the mountains of Kauai have never noticed mosquitoes until about a decade ago. These birds face one of the highest rates of extinction in the world! Of 41 honeycreeper species and subspecies, 17 are extinct, 14 are endangered, and only 3 are in decent shape.
Pox and malaria transmission in Hawaii depends on the climate, especially seasonal changes in temperature and precipitation that increase or decrease mosquito population. Warmer years (more mosquitoes) mean more deaths in these birds, while cooler years (less mosquitoes) mean less deaths from mosquito-borne illnesses. If temperatures continue to warm as mentioned, mosquitoes will continue to move into higher elevations and thrive, finally killing off the rest of the Hawaiian Honeycreepers.