Silvery-cheeked Hornbill

Arusha National Park is the most reliable location on the northern circuit. The tall montane forest holds a strong resident population and sightings are common around fruiting fig trees. The Ngorongoro forest rim and Lake Manyara's groundwater forest also hold them. They are not found in the open Serengeti or Tarangire.

The sealed cavity protects the female, eggs and chicks from predators, especially snakes and monkeys, during the vulnerable incubation and early chick-rearing period. The female moults her flight feathers while inside and is completely dependent on the male for food. She breaks out after roughly three to four months when the chick is ready to fledge.

They are primarily frugivores, with figs making up the largest part of the diet. They also eat other soft forest fruits, insects and occasionally small lizards. A single bird can consume over 100 figs in a day. Their fruit eating makes them critical seed dispersers for montane forest tree species.

The casque is a hollow bony structure on top of the upper bill. In silvery-cheeked hornbills it is cream coloured and prominent. Its exact function is debated but it likely plays a role in sound amplification, species recognition and possibly thermoregulation. It gives the bird its distinctive prehistoric profile.

They are large birds, roughly 75 to 80 centimetres long with a wingspan of around 50 centimetres. Males are slightly larger than females. They are the biggest hornbill species you will see in the highland forests of the northern circuit. The casque adds additional height to the head profile.

Outside the breeding season they form communal roosts of up to 100 or more birds and travel in loose groups between fruiting trees during the day. During the breeding season pairs become more solitary and focused on their nest cavity. The evening flight to roost is one of the most conspicuous bird spectacles in the highland parks.