When a bird is awakened to the sharp pain of teeth in its neck, it usually signals danger. Although birds have a very small brain, they are usually able to know that danger is very near when they feel the pain of teeth in their neck. This seems to work well while they are sleeping.
A sharp pain of teeth signals danger while birds are asleep
Birds detect the presence of a hawk through their keen eyesight and acute hearing. They also rely on alarm calls from other birds to alert them of potential danger.
No, they land before sleeping.
planes
Birds are often twitchy because they have a highly developed nervous system that helps them quickly detect and respond to potential threats in their environment. This heightened sensitivity allows them to stay alert and avoid danger, such as predators or other disturbances.
above danger
other birds
Danger - 1950 The Birds 5-40 was released on: USA: 31 May 1955
I think it might be their bedtime.
they sleeping silly!
Nope
tuck in there wings and twit as they close there eys.