HORNBILLS

‘Hornbills’ or ‘Bucerotidae’ are a family of Palaeotropical birds
commonly found in tropical Africa, subtropical Africa, Asia, and Melansia,
which are well-known for their unique appearance and behavior.

With long eyelashes on thier upper lids, dark eyes, a huge, colorful, decurved bill,
and its special ‘casque’ on top on their head,
hornbills become one of the most easily recognisible birds.

They have strong neck muscles as having two neck vertebrae bones in the spinal column attached together
in order to support their head and large bill.

Their feathers, however, are not as colorful as their bright-colored neck, face, and bill.
The body feathers are usually come in black, white, grey, and brown,
which are used together with the size and the shape of the casque to indicate the age and sex of Hornbills.

Variation in size and shape of Hornbills ranges from pigeon to large birds
with a hight of 30 to 120 centimerters long and weight between 100 grams and 6 kilograms,
in which males are often larger, heavier, and have a longer bill than females .

Hornbills are believed as ancient species arising for 30-35 million years ago (MYA),
though the most ancient evidence found is the one within 15 MYA,
which is a fossil of ground-hornbill’s single femur (known as “Bucorvus Brailloni”) found in Morocco,
and it is also the only one evidence leading to hornbills ancestor.
Beyond this, the evolutionary history of hornbills is clouded as lackking of fossil records

The first typical hornbills are called “Proto-Buceros or Proto-Tockus”.
Their evolution began in Africa with a lineage of an ancestral ground-hornbill.
They were a large, carnivorous bird, with a huge bill used to carry food.

Proto-Buceros basically parted into 2 groups:

One group stayed in Africa and eventually evolved as modern Tockus and Tropicranus.

Another group traveled across Asia and invaded the forest
then evolved and adapted the specializations for the best suit of their forest-life
i.e. they had to be frugivorous to survive, and that thus led to the development of their throat and pouch for efficient fruit handling.
Additionally, Asia is where the greatest diversity of forest hornbills occurs.

Once hornbills invaded to broad frugivore niche, they began to specialize and radiate.

For instance, the more advanced Bucorvus, resembling a modern Asia hornbill,
reinvaded Africa and gave rise to the African Forest Hornbill genera called “Ceratogymna and Bycanistes”