Migration and orientation by stars.

Indigo buntings migrate mostly at night.

  1. A test cage with an ink pad at the bottom and an open top that allows the bird to see the night sky.

  2. A top view of the cage shows that movement of the bird can be recorded as the bird tries to hop out of the cage.

  3. The left footprints show a bunting in spring (when it orients north).
    The middle footprints show a bunting in fall (when it orients south)
    The right footprints show a bunting on cloudy nights when stars are obscured.
Experiments in a planetarium show that indigo buntings orient themselves using patterns of stars around the North Star.