Movement Mondays
Join us for invited seminar talks by world-leading scientists and informal research and technique-oriented talks by CAM members where we discuss our latest and greatest ideas!
Next external speaker:
Jamie McLaren: Sept 8th
From inherited compass to course-correction: model and experimental evidence of inaugural songbird migration
University of Oldenberg
Summary: How first-time songbird migrants reach remote non-breeding grounds remains a central question in movement ecology. Most studies support a map-and compass paradigm, with first-time migrants following inherited compass headings, and adult migrants employing map-like course-corrective abilities, presumably by leveraging experienced geomagnetic gradients. Several recent studies are indicative of inaugural migratory course-correction, but lack control for celestial cues and consideration of threshold cue responses. I will first present modelling work predicting performance of inaugural compass-based migratory movement, including threshold magnetic signatures and partial self-correction using a sun compass. I will then highlight results from a recent translocation experiment of hatch-year neotropical migrants from Ontario to Saskatchewan across a strong E-W geomagnetic gradient, controlling access to celestial cues. Radio-tracking and stable-isotope analysis revealed surprisingly full course-correction, indicative of western-origin birds reiterating inherited (ESE) headings but eastern-origin birds shifting ca. 90° from WSW to SSE in an unexplored geomagnetic environment. This suggests inaugural course-correction may be contingent upon threshold magnetic signatures, possibly in conjunction with celestial information, motivating re-examination of the classic map-and-compass paradigm.
