Due to the existence of diseases like avian malaria and avian poxvirus, native forest birds are now restricted to high-elevation forests where cooler weather precludes mosquito breeding and parasite development. Unfortunately, even Kaua’i’s highest peaks are too low to prevent transmission during the warm summers. Under most climate change scenarios, even the forests on the highest mountains will soon experience year-round temperatures warm enough to promote disease transmission, which will have devastating consequences for most native bird species.
More details about the impact of climate change on Hawaiian forest birds can be obtained from the following paper: Large-Scale Range Collapse of Hawaiian Forest Birds under Climate Change and the Need 21st Century Conservation Options.