The bateleur (Terathopius ecaudatus) is a striking and distinctive raptor.
With such unusual colouration, adults are easily identified by the red colouration on the facial skin, beak, cere and feet, and by the predominantly black colouration of the feathers.
Adult size varies from 55-70cm, with an average weight of 2.25kg and a wingspan of 1.8m! Females are slightly larger than males and will have grey-white feathers appearing as a band underneath the wing on the outer side of the folded wing. Males lack this lighter grey band. An adult male is pictured here, while the juvenile pictured is likely a female, as the light grey colouration can be seen on the lower edge of the outer wing.
Juveniles are predominantly brown, with green facial skin and bill, and may easily be confused with a Brown Snake Eagle if seen from a distance. However, the distinctive short tail and brown eyes are characteristic of the bateleur.
Did you know?
- It can take up to seven years for a juvenile bateleur to develop full adult plumage. Over a span of four moults, the juvenile slowly begins to “morph” into adult plumage, becoming mottled and darker with each moult, and shortening the tail feathers each time. Sexual dimorphism, or the difference in colouration between adult males and females, can be seen developing from as early as two-to-three years in females, and from five years in males - particularly with wing patterning. There is also a morph of the adult bateleur, although rarely recorded, where adults may have creamy-buff colouration on the back, rump and tail.
- The underside of the wing can also be used to differentiate between adult males and females, with males having a much wider black band of feathering on the edges of the wing, taking up almost half the underwing colouration, while females have only a thin band of black feathers on the wing tips, and predominantly white underwing feathers.
Fun Facts:
- Researchers do not know exactly what causes eye colour changes from juvenile to adult birds. Juvenile bateleurs have brown irises, but adults have red irises - but nobody knows exactly why this change happens in birds, or what drives it!
- Bateleurs are also sometimes referred to as short-tailed snake eagles and are classified within the same sub-family of birds, being closely related to the snake eagle family.
Words by Tess Woollgar. Images courtesy of Josh Hibbett and Maureen Kirk.