Birds fly across oceans for days at a time while migrating. But they still manage to get some shut-eye.

BIRDS
Urban birds may also be more territorial and aggressive than their more laid back rural counterparts.
Experts wondered if living so close to humans and other falcons would change the raptors’ naturally monogamous mating habits.
Researchers believe the discovery could be the key to identifying other ancient bird species.
The funny commercial has been called "idiotic" by figures in the advertising community.
3. They form gangs.
Here are five animals that made sure justice was served.
"Predictably Philandering Females Prompt Poor Paternal Provisioning"
A study found that adult zebra finches speak differently to baby birds than they do to one another, and that their repetitive language seemed to help the young birds learn to sing.
Their iridescent eyespots stay still while other parts of the feather oscillate, creating a captivating display for peahens.
The birds never forget a face, or how it has wronged them.
Thanks to frostbite, Philip the duck was missing his webbed appendages. Now, he's able to live on his own.
In the study, Brown skuas developed a grudge against any researcher who repeatedly poked at their nests.