Long-term population monitoring: Lessons learned from an endangered passerine in Hawai‘i

Obtaining reliable population estimates is crucial to monitoring endangered species and developing recovery strategies. The palila (Loxioides bailleui) is an endangered seed-eating Hawaiian honeycreeper restricted to the subalpine forests of Mauna Kea, a volcano on the island of Hawai‘i, USA. The species is vulnerable to extinction primarily because >90% of the population is concentrated in