The genus Spilornis is represented by 2 species in Borneo, the widespread and Borneo’s most common raptor S. cheela (Crested Serpent-eagle) and the rare endemic S. kinabaluensis (Mountain Serpent-eagle) occupying the montane habitats not frequented by the former.

The Mountain Serpent-eagle is distinguished from the Crested Serpent-eagle by having longer wings, a darker plumage with black throat and broader white band on the tail.  When seen flying  from a long distance, it is probably easier to id from the voice, with the final note of the Mountain being more sustained.

Mountain Serpent-eagle, Mt Kinabalu

Crested Serpent-eagle, Tabin Wildlife Resort