Life-History and Ecophysiological Adaptations to Migration in Australian Birds

Bird migration in the southern hemisphere: a review comparing continents

“…Like the Yellow-faced Honeyeater, the partially migratory Tasmanian population of Silvereyes display migratory restlessness and premigratory fattening (Chan 1994(Chan , 1995 and orientation appropriate to the season of migration using both celestial and magnetic cues (Wiltschko et al 1998a(Wiltschko et al , 1998b(Wiltschko et al , 2001). In both species, endogenous control mechanisms regulate migration and the seasonal cycle, as the experiments with migratory restlessness and diet revealed (Munro 2003). Thus with respect to endogenous control and orientation, these southern hemisphere migrants display mechanisms similar to northern hemisphere species, especially those travelling from Europe to Africa (Gwinner and Helm 2003).…”

“…Most understanding of migration physiology comes from nocturnal migrants adjusting to northern hemisphere seasons. There is little research on southern hemisphere species experiencing less severe but less predictable seasonality or that migrate by day rather than at night (Munro 2003). Questions to consider concern similarities or differences between the migratory syndromes of northern and southern hemisphere species and whether these syndromes reflect differences in environments within and between the two hemispheres.…”

“…The honeyeater migrates north-east up the eastern coast and along the Great Divide and associated tablelands of Australia in the autumn until it reaches south-eastern Queensland whereupon it turns north-west. Like northern migrants these birds show increased activity in laboratory cages at the time of migration, change diet (to feeding on more nectar), deposit fat, and orient in Emlen funnels in the direction predicted by the migration pathway, including the change in orientation from north-east to north-west at mid-course (Munro and Wiltschko 1992;Munro et al 1993;Munro and Munro 1998;Munro 2003). These diurnal migrants use both celestial and magnetic cues for orientation like well-studied nocturnal northern migrants (Wiltschko and Wiltschko 1995).…”

“…The tendency of these latter groups to occur in drier habitats with patchier resources may contribute to the difference from hummingbirds. So too might differences in physiology and foraging ecology, both of which merit further study with respect to austral migration (Munro 2003;and below).…”

“…These have been extensively studied in northern hemisphere migrants and include mechanisms of orientation, timing of the annual cycle, and metabolic changes to prepare for migratory flight (Munro 2003;Åkesson and Hedenström 2007;Ramenofsky and Wingfield 2007). In these northern migrants, endogenous annual time programs synchronise migratory activity with environmental cues such as photoperiod (Gwinner and Helm 2003).…”