Clock-shift experiments with homing pigeons: a compromise between solar and magnetic information?

摘要: In adult homing pigeons, the deflections induced by a 6-h clock-shift are often markedly smaller than predicted on basis of difference in sun azimuth. To look for possible reasons, we performed experiments with releasing birds small bar magnets that interfered their magnetic compass. Initial orientation and performance control living natural photoperiod were not affected any way. Otherwise untreated pigeons whose internal clock had been reset 6 h showed about 60% size. Brass bars did affect behavior clock-shifted birds. Magnets, however, increased deflection significantly to 90% size; majority releases, confidence interval included expected direction. These findings suggest reduced observed be attributed pigeons' use compass: when locate home course, they seem combine directional information from compass geomagnetic field.