Bird Communities in the Karst Forests of Teluk Sumbang, East Kalimantan, Indonesia

Birds are important components of karst forests. Their presence can be an indicator for habitat occupied. We identified bird communities in the karst forests of Teluk Sumbang, East Kalimantan. Bird sampling was done in hill karst forests and coastal karst forests. We employed a point count method by following transects. Observers walked constantly along transect and stopped every distance of ±200 m to record all sighted birds for 10-15 min. We found 89 bird species: 67 bird species were identified in hill karst forest and 33 bird species were recorded in coastal karst forests. Eleven bird species were found in both study sites. The score of diversity, species richness, and evenness indices of hill karst forests was higher than that in coastal karst. A t-test revealed that there was a significant difference in diversity index between coastal and hill karst (T = 2.016, p = 0.039). Birds characterized by a wide range of distribution and were able to adapt to various types of environments, particularly secondary forests, were most dominant. Nevertheless, the karst forests of Teluk Sumbang were also essential habitat for threatened and protected bird species.