Yes, what does a tailorbird do at night? Or all diurnal birds for that matter. Why, some but not all sleep. Many waders feed at night when the mudflats are exposed due to low tide. So they cannot afford to sleep. Other birds feed at night because it is safer to do so when many predators are asleep.
Many birds sleep with the head turned and resting on the shoulder and the bill tucked among fluffed up plumage of the back. They may sleep standing up of sitting with the feet locked on the perch. Some sleep clinging to tree trunks with their toe nails eg. treecreeper.
Where birds sleep is important.
Some species come together in communal roosts to sleep, either the year round or only during the non-breeding season. Snuggling together helps to significantly reduce heat loss. Hole nesters roost inside their cavities. Other birds sleep in groups or alone. They usually sleep under cover of vegetation.
But this apparently was not so with the tailorbird.
In April 2007, Ng Bee Choo and Morten Strange were holidaying in Taman Negara, Malaysia. On their way to dinner one night, they stumbled on a small ball of feathers attached to the leaflets of a palm sapling. On recognising that it was a sleeping bird, Bee Choo rushed back to her room to get a camera. Not wanting to disturb the sleeping bird, she did not switch on the flash.
Her image of the sleeping tailorbird is shown above. It shows a smallish ball of feathers, the two feet locked on the base of the palm leaflet. The head of the bird was tightly tugged under a wing such that the bill was totally out of sight. The feathers were fluffed. These are the ways birds keep warm.
At one end of the ball of feathers was a small, narrow tail, distinctly obvious. The rufous crown and one of the black shoulders can be distinguished.
Ng Bee Choo & Morten Strange