Hornbills are big - about 70 cm long from beak to tail, the size of a large house cat. The casque on top of the beak isn't heavy; it is mostly hollow and helps the bird's call carry for kilometres through the forest.
They eat fruit, insects, and sometimes small lizards. They have a clever trick for swallowing: they toss the food up in the air with the tip of their beak and then catch it perfectly in their throat. Hornbill couples often feed each other, lifting fruit beak-to-beak.
The most amazing thing about hornbills is how they nest. The mother climbs into a hole in a tree, and she and her partner seal the hole almost closed with mud, leaving just a tiny slit. The mother stays inside safe with the eggs and chicks for weeks while the father brings food through the slit. When the chicks are ready, the family breaks the seal open.
Hornbills disappeared from Singapore around 100 years ago. Then in the 1990s a few flew over from nearby islands and stayed. Singapore put up special wooden nest-boxes to welcome them. Today you can see them flying right across the city, sometimes landing on apartment balconies.