An interesting article appeared in the December 1995 issue of Bird Watching
magazine in the UK. Part of the article follows:

"The sight of Cormorants 'drying' their wings will never be the same again
according to German scientists.
Experiments in a German zoo have suggested that cormorants spreading their
wings are actually warming up the cold fish they have just swallowed.
In tests, every bird fed cold fish flapped its wings and spread them for
about 20 minutes, while less than a quarter of those fed warm meals spread
their wings.
According to experts, this would not only be useful in aiding digestion, but
it could help other cormorants, too [identifying good feeding areas]"

Vic Smith