Magnetic Remanences in Migratory Birds

Abstract

In connection with indications of the magnetic field detection in migratory birds, the measurements of magnetic remanences were carried out in both the migratory birds (Rustig Bunting and Reed Bunting) and the non-migratory birds (Siberian Meadow Bunting and Tree Sparrow) by means of SQUID magnetometer. Regardless of whether the species was migratory or not, neither heads nor neck musculatures indicated any presence of intrinsic magnetic materials related to the sensory mechanisms. The natural remanence and the induced remanence were of the orders of 10^-8-10^-7 e. m. u. and of 10^-7-10^-6 e. m. u. respectively. The magnetic sensor of birds for a compass reception is discussed.