Like the island’s mammals, Borneo’s bird wildlife is similar to that of peninsular Malaysia and Sumatra. The island’s lowland forests include 8 hornbill species, 18 woodpecker species and 13 pitta species, along with 2 species found nowhere else in the world (endemic): the black-browed babbler (Malacocincla perspicillata) and the white-crowned shama (Copsychus stricklandii).

Borneo’s bird fauna is slightly less rich than that of Sumatra but it has more endemic species, particularly in montane areas. The reason for this is that in geological time, mountains remained as 'evergreen islands' when Borneo's drier lowlands were periodically linked with the Asian mainland.

Borneo hornbills - cultural and ecological symbols

Hornbills are of considerable cultural importance and abstract forms of their beaks can be found on many Dayak motifs. Ecologically, hornbills such as the bushy-crested (Anorrhinus galeritus), helmeted (Rhinoplax vigil), and the great rhinoceros (Buceros rhinoceros) are important seed disperses of many fig trees (Ficus species).

The 2 largest hornbills, the rhinoceros hornbill and the helmeted hornbill, are declining as they have been affected by the removal of their large nesting trees. They are also hunted for their meat and for their tail feathers, used for traditional costumes and dancing.

Hunting is causing populations to decline or become locally extinct, a problem that is made worse by the birds’ slow breeding rate and low natural densities. Five of the 8 hornbill species are now listed as "Near Threatened" on the IUCN's Red List of Threatened Species.

Although these long-lived birds often persist in logged-over forests for many years, they do not breed if there are no suitable cavities in large trees.

A stopover on Borneo for long-distance flyers

Every year, Borneo is visited by many bird species from temperate regions that choose to spend winter on the island.

This period corresponds to the fruiting season, which provides much needed food resources for frugivorous (species that eat only, or mostly, fruit) migrants. Mt. Kinabalu (Sabah), is one of the areas in Borneo that provide relatively stable fruit resources for many frugivorous birds.