Bird Navigational Techniques

Sun Compass -- Some birds seem able to negotiate the proper direction only if they have a clear view of the sun. Even night migrants appear touse the sun as a cue, as most take off during twilight.

Star Compass -- Night migrant orient themselves in the proper direction under clear, starry skies but become disoriented when it is cloudy. Night-migrating birds learn and orient by the spatial relationships among the constellations, rather than by using information supplied by any single star.

Odor Map -- Some short-distance migrants use an "odor map" to return to nesting and wintering sites. Studies show that young pigeons learn the odors -- carried by the wind -- which reach their home sites.

Magnetic Map -- Migratory birds may rely on an instinctual map to find their way back to nesting or wintering sites. Magnetic disturbances may interrupt these abilities.

Magnetic Compass -- Sever kinds of birds appear to possess a built-in magnetic compass to use on cloudy days. Birds tested in a controlled environment showed that they knew which direction to migrate even without the sun or stars.