Circaetus cinerascens (Western banded snake-eagle) 

Enkelbandslangarend [Afrikaans]; Kleine grijze slangenarend [Dutch]; Circaète cendré [French]; Band-Schlangenadler [German]; Águia-cobreira-de-cauda-branca [Portuguese]

Life > Eukaryotes > Opisthokonta > Metazoa (animals) > Bilateria > Deuterostomia > Chordata > Craniata > Vertebrata (vertebrates)  > Gnathostomata (jawed vertebrates) > Teleostomi (teleost fish) > Osteichthyes (bony fish) > Class: Sarcopterygii (lobe-finned fish) > Stegocephalia (terrestrial vertebrates) > Tetrapoda (four-legged vertebrates) > Reptiliomorpha > Amniota > Reptilia (reptiles) > Romeriida > Diapsida > Archosauromorpha > Archosauria > Dinosauria (dinosaurs) > Saurischia > Theropoda (bipedal predatory dinosaurs) > Coelurosauria > Maniraptora > Aves (birds) > Order: Falconiformes > Family: Accipitridae > Genus: Circaetus

Western banded snake-eagle, Poli, Cameroon. [photo Nigel Voaden ©]	Immature Black-chested snake-eagle, Gambia. [photo Bill Clark ©]

Distribution and habitat

Occurs in sub-Saharan Africa from Senegal to Ethiopia, while largely absent from the lowland forests of the DRC and other west African countries, south to northern Tanzania, with a separate population from southern DRC through Angola and Zambia to southern Africa. Here it is uncommon in northern Botswana, the Caprivi Strip (Namibia), northern Zimbabwe and northern Mozambique, generally favouring riverine forest and woodland, such as tall Mopane (Colosphermum mopane) woodland in the Zambezi River valley, although it may occasionally hunt in adjacent open habitats.

Movements and migrations

Probably sedentary in southern Africa, although it is for some reason it is more scarce in summer in Zimbabwe.

Food 

It mainly eats snakes (especially arboreal ones), doing most of its hunting from a perch, where it stays immobile for hours while searching for prey. Once it spots something it glides to the ground or canopy and plucks the animal up before returning its perch to feed. The following food items have been recorded in its diet:

• Vertebrates
  • reptiles
    • snakes
      • Dispholidus typus (Boomslang)
      • Philothamnus (green snakes)
      • Bitis arietans (Puff adder)
      • Naja (cobras)
      • Crotaphopeltis hotamboeia (Herald snake)
      • Python natalansis (South African python)
    • lizards
      • Varanus niloticus (Water monitor)
    • newly hatched tortoises
  • frogs
  • small rodents
  • fish
• Invertebrates
  • Coleoptera (beetles)

Breeding

• Probably a monogamous solitary nester, performing spectacular aerial displays in which it dives straight down with its wings folded before stabilising again.
• The nest is a platform of sticks with a cup set into it, lined with green leaves such as Munondo (Julbernadia globiflora). It is typically placed about 10-18 metres above ground in the canopy of a large tree, especially the following species:
  • Acacia polyacantha (White thorn)
  • Acacia nigrescens (Knob thorn)
  • Brachystegia boehmii (Mufuti)
  • Garcinia livingstonei (African mangosteen)

  The nest tree is almost always covered in creepers, including:

  • Artabotrys brachypetalus
  • Bauhinia galpinii (Pride of the cape)
  • Capparis tomentosa (Woolly caper-bush)
  • Grewia flavescens (Sandpaper raisin)
  • Jasminum fluminense
  • Pteralobium stellata
• Egg-laying season is from about December-February.
• It lays a single egg, which is incubated for an estimated period of 36-42 days.
• The chick is fed by both parents, leaving the nest after roughly 56 days.

Threats

Not threatened globally, although degradation of riparian forest by humans and African elephants (Loxodonta africana) seem to have decreased its population in Zimbabwe and Namibia.

References

• Hockey PAR, Dean WRJ and Ryan PG 2005. Roberts - Birds of southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town.