Some members of the birds in the Hornbill family have a very interesting breeding behaviour.
The female finds a suitable hole in a tree, and they (male and female) build up the opening untill just a slit remains, using mud and guano.
She then moults all her feathers, using them to pad and insulate the nest, before laying her eggs. She remains "built in" to the nest right through the incubation period and untill the chicks are ready to fledge.
During this period, she and the chicks are completely dependent on the male bringing food regularly.
I was recently fortunate enough to witness a little bit of it...
