Orientation in birds. The sun compass

Area of Science:

• Animal behavior
• Navigation
• Ornithology

Background:

• The sun compass, a navigational tool used by birds, was first observed in caged birds exhibiting migratory restlessness.
• Early research indicated that birds utilize the sun's azimuth (horizontal position) but not its altitude (vertical position) for orientation.

Purpose of the Study:

• To investigate the role of the sun compass in bird navigation, particularly in homing pigeons.
• To provide evidence for a map-and-compass navigational system in birds.

Main Methods:

• Directional training and clock-shift experiments with caged birds.
• Homing experiments with pigeons, including clock-shift manipulations.
• Analysis of navigational accuracy under various latitudes and solar conditions.

Main Results:

• Birds accurately use the sun's azimuth, with laboratory accuracy around +/- 3 to +/- 5 degrees.
• Caged birds at mid-northern latitudes could compensate for the sun's movement, but not near the equator.
• Homing pigeons demonstrably use the sun compass for initial orientation, achieving ~3-degree accuracy even at the equator during equinox.

Conclusions:

• The sun compass is a crucial component of avian navigation, supporting the map-and-compass theory.
• Pigeons exhibit remarkable navigational abilities, utilizing the sun compass effectively across diverse latitudes and solar conditions.
• Preliminary findings suggest potential delays in homing pigeons' internal timekeeping (ephemerides).