Magnetic compass orientation in the yellow-faced honeyeater, Lichenostomus chrysops, a day migrating bird from Australia

Abstract

In Australia, the southern populations of the yellow-faced honeyeater, Lichenostomus chrysops (Meliphagidae), perform annual migrations, with routes following the eastern coastline. In order to assess the role of magnetic cues in the migratory orientation of this diurnal migrant, its directional behaviour was recorded in recording cages under natural and experimentally manipulated magnetic-field conditions. During autumn the birds tested indoors in the local geomagnetic field showed a directional change from north initially to northwest later in the season (Fig. 1 a, b), which corresponds well with the general pattern of movement of this species in the field. Deflecting magnetic north to ESE resulted in a clockwise shift of the mean direction by 77° and 71°, respectively (Fig. 1 c, d), while no significant directional tendencies were observed in a magnetic field with a compensated horizontal component (Fig. 1 e, f; see Table 1). In outdoor tests in spring, the birds preferred southerly directions when tested in the local geo-magnetic field. In a magnetic field with a reversed vertical component (i.e. with an inclination pointing down instead of upwards) the birds reversed their directional tendencies and oriented northward (Fig. 2, Table 2). These results clearly show: (1) that yellow-faced honeyeaters can use the magnetic field for direction finding, and (2) that their magnetic compass functions as an “inclination compass”, as has been shown for several holarctic migrants.