Magnetoreception in seabirds

Abstract

**Abstract:** Seabirds are some of nature's greatest navigators, often traversing tens of thousands of kilometers a year over visually sparse terrain. The mechanisms by which this is achieved are, however, frustratingly elusive. In songbirds we know that long-distance movement is partly underpinned by an ability to sense the Earth's magnetic field, though outside of this clade evidence for magnetoreception is sparse and, in some instances, highly equivocal. There is, then, considerable interest in understanding a) whether seabirds use the Earth's magnetic field to navigate and b) if so, how? Here, we use historic ringing data to investigate whether Manx shearwaters (Puffinus puffinus) use magnetic cues when relocating their natal site following first migration. Using slight (but measurable) changes in the Earth's magnetic field, we find that changes in latitude between ringing and recovery are predicted by changes in the inclination of the Earth's magnetic field. We find that small changes in inclination between when a bird fledges and when it returns from first migration correlate with probabilistic changes in latitude at recruitment, in doing so quantitatively fulfilling a priori predictions as to the magnitude and direction of latitudinal shift. This, we believe, suggests that a) natal magnetic inclination is learnt prior to fledging and b) is used to provide latitudinal information when making the first return trip from the wintering grounds. **Authors:** Joe Wynn¹ ¹University of Oxford