Most native forest birds are found higher in elevation (above ~4500 feet). These are areas with fewer invasive plants and often have fences to protect the forest from ungulate damage, but the most important feature of these areas is the high elevation itself. Disease carrying mosquitos do not typically survive at these altitudes due to cooler temperatures, and the plasmodium (the parasite) for avian malaria does not typically develop. Given these restrictions, it can be difficult to find Maui’s native forest birds. There are still a few places that people can go to see these beautiful birds.
Haleakalā National Park (HNP) holds many of the places where native birds can be seen. Hiking into the crater, along the Halemau'u Trail, 'Apapane and Hawai'i 'Amakihi can be heard, and once a hiker finally reaches Palikū Cabin at the far end of the crater, 'I'iwi and sometimes a Maui 'Alauahio will greet the visitor. Hosmer Grove is a well-known birding location on the island and one can find 'Apapane, Hawai'i 'Amakihi, and 'I'iwi chirping from high up in the eucalyptus or low down in the Māmane. Photographers can be seen staked out on the short nature loop there where sometimes Maui 'Alauahio can be seen. See Birding Hikes for more information about guided hikes that are led into The Nature Conservancy's Waikamoi Preserve. These hikes have a better chance of seeing the rarer honeycreepers, Kiwikiu and 'Akohekohe.
The Kula Forest Reserve also offers a lesser known opportunity to observe Maui’s native forest birds. A 3.5 mile hike will bring you through a variety of different habitats, from tropical ash and eucalyptus trees, to a variety of cypress, cedar, pine, and even giant redwoods (all non-native habitat with some native plants dispersed throughout the forest). This loop includes the Haleakalā Ridge Trail, Plum Trail, Tie Trail, and Redwood Trail and one can observe 'I'iwi, 'Apapane, Hawai'i 'Amakihi, and Maui 'Alauahio. The southwestern portion of the hike, along the Haleakalā Ridge Trail offers your best opportunity to see, hear, and/or photograph all of these birds. With low shrubby vegetation and high bird densities, this area is sure to provide a wonderful display of color and song. At times, all four species can be seen immediately in the parking lot.
Besides east Maui, there are a few other trails on West Maui where birders can see 'Apapane and Hawai'i 'Amakihi and possibly an 'I'iwi, which are very rare on West Maui. Check out the Waihe'e Ridge trail or the Kapalua Trails.
Check out the Hawai'i Audubon Society's Guide to Birding on Maui and Maui Bird Guide Tour Company.