Palila, once found on multiple islands, occupy a small, shrinking subalpine range on the southwestern slope of Mauna Kea. As the last finch-billed honeycreeper in the main islands, they depend on the seeds of māmane trees, fruits of naio trees, and arthropods. The habitat’s carrying capacity has decreased due to decades of habitat destruction by introduced ungulates and severe drought during 2000–2013. These factors led to a 67% decline in the species’ abundance from 2003 to 2016. The drought has ended, and over 23,000 sheep and goats were removed between 1980–2016 in an effort to achieve the court-mandated eradication. The partners have planted over 143,000 native plants to restore the native forest Palila depend on, including new efforts at treeline to mitigate climate change effects to the dry forest ecosystem. Significant changes in regional land management, including community involvement in the restoration and outreach about protecting Mauna Kea, will also benefit Palila and other native species.
Although māmane-dominated forest is recovering in response to management, naio trees are succumbing to an alien pest and weeds continue to spread across large areas. Palila have slow reproductive rates and may require decades to respond to increasing tree cover and other habitat improvements. Although their decline has slowed, the species continues to decrease, with only approximately 1000 birds remaining. Recovery criteria for Palila include greater protection for the current (“core”) population and establishing multiple self-sustaining populations, which potentially will begin with releasing captive-bred Palila on northern Mauna Kea.