Birds in good condition slept more during the day than those in poor condition, the scientists found, perhaps because those birds didn't need to spend as much time foraging for food. And at night, the robust birds generally slept facing forward, with their heads erect. The leaner birds, on the other hand, literally tucked themselves in at night, swiveling their heads around and nestling them under the feathers on their shoulders.
Izinyoni ezisesimweni esihle zilala kakhulu emini kunalezo zisesimweni esingesihle, lokhu kuthulwe ngososayensi, mhlawumbe ngoba lezo zinyoni zazingadingi ukuchitha isikhathi esiningi zizifunela ukudla. Futhi ebusuku, izinyoni ezinamandla ngokuvamile zazilala zibheke phambili, izinhloko zazo zimile. Izinyoni ezinamafutha ngakolunye uhlangothi, bazifaka ngokoqobo ebusuku, zishwibise amakhanda azo zizungeza ngaphansi kwezimpaphe emahlombe azo.