Sleep.
birds live in nests in a tree and sleep in a nest
they fly why they sleep
Most birds sleep 4 to 5 hours a day. Birds will go to sleep after the sun sets. Birds awaken when the sun rises in the morning.
they sleep like we sleep and they sleep why we sleep because we need energy and strength
Yes
Birds do not sleep in nests as you think, they sleep in the same places they inhabit in the daytime.+++They sleep on the nest if incubating eggs or rearing young - the only time they use nests - otherwise many of them find sheltered roosts reasonably safe from weather and predators.
they sit
Of course. Advanced life forms always need sleep. Some birds rest on branches or in a nest. Others, like the albatross, sleep for a couple hours in the air as they glide.
well in the world the only birds that can sleep standing up is the flamingo. flamingos stand on one leg with their head in their body
They find a safe spot to perch, wrap their little claws tightly around it, and close their eyes. Birds are light sleepers.
Who says birds don't poop in water! Seagulls do! I know ... got sprayed by one last summer. Yuk! Birds as a whole can and do poop in water if they happen to need to go when they are near water. But, pet parrots (whether near your pool or not)a parrot will tend to avoid pooping where they sleep and where they eat if they are provided with sufficient space to be able to easily avoid having to do so.