Crested serpent eagle, Spilornis cheela (Latham, 1790) of Borneo.

Spilornis cheela (English: Crested Serpent Eagle) is a bird of prey from the Accipitridae family and is classified within the serpent eagles (Circaetinae). The species is recorded on Borneo according to IOC-based taxonomy; the subspecies Spilornis cheela pallidus (northern Borneo) and Spilornis cheela richmondi (southern Borneo) are listed for Borneo in particular. (In the same checklist, the Kinabalu snake eagle Spilornis kinabaluensis is also listed as a separate species on Borneo.) The genus name Spilornis is derived from the ancient Greek spílos (‘spot’) and ornis (“bird”); the species epithet cheela comes from the Hindi word chīl/cheelā (‘milan’) and was used in the first description (Latham, 1790).

In terms of behavioural ecology, the species is diurnal and uses acoustic signals and conspicuous aerial displays; repeated dive flights and joint circling or gliding are described as part of the courtship ritual. It is often observed circling over forest areas; its call is described as a shrill, usually three-note sound. Its diet consists mainly of snakes (including venomous species); other vertebrates such as small mammals and birds as well as amphibians are also recorded. It hunts both from a perch (waiting hunt) and in search flight or while gliding.