How does rising atmospheric CO2 affect marine organisms?

Click to locate material archived on our website by topic

Flexibility in Destination Choice in Long-Distance Migratory Birds
Dias, M.P., Granadeiro, J.P., Phillips, R.A., Alonso, H. and Catry, P. 2011. Breaking the routine: individual Cory's shearwaters shift winter destinations between hemispheres and across ocean basins. Proceedings of the Royal Society B 278: 1786-1793.

In regard to the challenges to long-distant migratory animals produced by potential changes in climate, the authors write that "existing phenotypic plasticity per se may allow, within certain limits, the persistence of species and populations (even if in suboptimal circumstances), gaining time for selection to act, or for more favorable environmental conditions to be restored," noting that "there is strong evidence that recent climate changes may have already impacted migratory behavior" as it pertains to birds, citing the works of Fiedler (2003) and Newton (2008).

What was done
Dias et al. evaluated individual flexibility in the migration strategies of a highly pelagic seabird, the Cory's shearwater (Calonectris diomedea). This they did by tracking the migration of 57 of the birds that spent the breeding season at Selvagem Grand Island (30°02' N, 15°52' W) via leg-mounted geolocators weighing approximately 3.6 grams that were deployed at the end of the breeding seasons of 2006, 2007 and 2008 and recovered in the early stages of the subsequent breeding seasons.

What was learned
The five researchers report that fourteen birds that were tracked for more than one non-breeding season, "showed a remarkable capacity to change winter destinations between years," with some shifting all the way from the South Atlantic to the North Atlantic, and from the Atlantic Ocean to the Indian Ocean. And they indicate that individual birds "also showed flexibility in stopover behavior and migratory schedule."

What it means
Dias et al. conclude that their results suggest that Cory's shearwaters are in a good position "to face the consequences of a changing environment," adding that "whether Cory's shearwaters are unusual in this respect, or whether future analyses will reveal that flexibility in migration strategies is a more general trait of marine migratory fauna is something that repeated tracking of individuals in coming years should clarify."

Fiedler, W. 2003. Recent changes in migration behavior of birds: a compilation of field observations and ringing data. In: Berthold, P., Gwinner, E. and Sonnenschein, E. (Eds.). Avian Migration. Springer, Berlin, Germany, pp. 21-38.

Newton, I. 2008. The Migration Ecology of Birds. Academic Press, London, United Kingdom.

Reviewed 13 July 2011