A Bird Hammock
In his voyage to India, Sonnerat speaks of a Cape titmouse, the nest of which is made of cotton and is shaped like a bottle. While the female is hatching inside, the male, a most watchful sentinel, remains outside in a pouch or hammock, fixed to one side of the neck of the nest. When his mate moves off and he wishes to follow her, he beats the opening of the nest violently with his wing until he closes it, in order to protect the young from enemies.