Las aves migradoras que acuden a criar al Ártico, ¿lo hacen porque allí hay menos depredadores?

Esta es la conclusión a la que llega este interesante estudio publicado ayer en la muy prestigiosa revista Science. El resumen dice así:

Science 15 January 2010:
Vol. 327. no. 5963, pp. 326 - 327

Lower Predation Risk for Migratory Birds at High Latitudes
L. McKinnon,* P. A. Smith, E. Nol, J. L. Martin, F. I. Doyle, K. F. Abraham, H. G. Gilchrist, R. I. G. Morrison, J. Bêty

Quantifying the costs and benefits of migration distance is critical to understanding the evolution of long-distance migration. In migratory birds, life history theory predicts that the potential survival costs of migrating longer distances should be balanced by benefits to lifetime reproductive success, yet quantification of these reproductive benefits in a controlled manner along a large geographical gradient is challenging. We measured a controlled effect of predation risk along a 3350-kilometer south-north gradient in the Arctic and found that nest predation risk declined more than twofold along the latitudinal gradient. These results provide evidence that birds migrating farther north may acquire reproductive benefits in the form of lower nest predation risk.

Acompaña a este artículo en Science otro que dice:

Science 15 January 2010:
Vol. 327. no. 5963, pp. 276 - 277

Explaining Bird Migration
Olivier Gilg1 and Nigel G. Yoccoz

Arctic shorebirds can travel tens of thousands of kilometers every year as they fly along intercontinental flyways from their southern wintering grounds to their remote, harsh breeding sites. How these birds solve the navigational and physiological constraints has been largely answered, but why they migrate is still a question with many possible answers (1). On page 326 of this issue, McKinnon et al. (2) present a continent-wide study that points to predation as a driving mechanism for migration. The study also elucidates the role of predation in shaping Arctic terrestrial biodiversity.

Parte de los trabajos de campo que en los que se ha basado el primer artículo se desarrollaron en el norte de la isla de Ellesmere, de donde venía cada invierno a A Coruña, como recordarán los más veteranos lestores de este blog, una hembra de vuelvepiedras.

Si estais vagos y no os apetece leeros de corrido el primer artículo, aquí tenéis un resumen.