The Yellow-bellied Tyrannulet (Ornithion semiflavum) is a species of bird in the Tyrannidae family. It is found in Belize, Costa Rica, Guatemala, Honduras, Mexico, and Nicaragua. Its natural habitats are subtropical or tropical moist lowland forests and heavily degraded former forest.
Source
BirdLife International 2004. Ornithion semiflavum. 2006 IUCN Red List of Threatened Species. Downloaded on 26 July 2007.