Some observations indicate that birds might use the sun as a visual cue to determine compass directions. Starlings, for example, seem able to negotiate the proper direction only if they have a view of the clear sky and sun; cloud cover seems to induce confusion. In an experiment in which the sun's apparent position was changed with mirrors attached to an orientation cage containing starlings, observers noted that the direction of the starlings' hopping, which earlier had been correlated to the direction they chose to migrate, was shifted accordingly.

Even birds that migrate exclusively at night pay considerable attention to the sun. At first this may seem odd because, after all, the sun is not visible to the nocturnal birds when they are flying. On the other hand, it is a predominate feature in the sky at a time of day (dusk) when birds may well be making decisions about whether to fly that night and in what direction. Radar studies have shown that most night migrants take off during this twilight period.

Like many other animals (including insects, fish, reptiles, and mammals), birds are endowed with a built-in clock that tells them the time of day. Using this internal clock, young pigeons, at least, learn the sun's path of movement across the sky. Many birds are known to have an internal clock, and many are known to have a sun compass, but it is only in pigeons that ornithologists can watch the learning process develop.