Wiltschko R, Nohr D, Wiltschko W
Science. 1981 Oct 16;214(4518):343-5. doi: 10.1126/science.7280697.
Homing pigeons that had never seen the sun before noon could not use the sun compass in the morning; nevertheless they were homeward oriented. When such birds carried magnets, however, they were disoriented, suggesting they were using a magnetic compass. These findings indicate that the magnetic compass is available to pigeons whether or not the sun compass has been established and that the magnetic compass is apparently the first source of compass information.
从未在中午之前见过太阳的信鸽在早晨无法使用太阳罗盘；然而它们却能找到回家的方向。然而，当这些鸽子携带磁铁时，它们就迷失了方向，这表明它们在使用磁罗盘。这些发现表明，无论太阳罗盘是否已经形成，鸽子都可以使用磁罗盘，而且磁罗盘显然是罗盘信息的首要来源。
