Now, a new study in the journal Science emphasizes another reason the long voyage may be worth it for birds: fewer predators.
Titled “Lower Predation Risk for Migratory Birds at High Latitudes," the study finds that, the farther north birds go in the Arctic, the lower the risk of predation. Fewer predators mean that vulnerable young have greater chance of survival.
Even accounting for the huge energy cost of the long voyage, having young in the Arctic improves reproductive success.
… An accompanying article entitled “Explaining Bird Migration” offers some context. More than anywhere else, Arctic ecosystems are shaped by predator-prey interactions, say the authors. That’s partly because there are so few species to begin with. The few species that can survive the harsh conditions — lemmings, arctic fox, and snowy owls, among others— are, by definition, major players in the ecosystem.
… Also in bird migration news this week, the arctic tern was crowned "king of the commuters."
"A high-tech tracking survey has revealed that the annual migration of the Arctic tern is the longest in the animal kingdom – with some birds flying the equivalent of three journeys to the moon and back over their lifetimes," reports New Scientist.