NSF – Except when the wind blows sea ice away, these Antarctic seas are covered by ice floes–pack ice–and it is in these ice-covered waters that Adélie penguins find the fish and krill that they eat.
However, in certain instances, there can be too much ice. Penguins are really great at swimming but are slow at walking. Areas of open water allow the penguins to be more efficient at foraging and bringing back food to their chicks. For their size, Adélies can dive deeper and can hold their breath longer to reach farther under ice floes, than can penguin species that avoid sea ice.
Not surprisingly, then, the Adélie colonies are highly sensitive to minor changes in the amount of sea ice, which itself is responsive to changing climate.
The ocean-going skills of the penguins are important when it comes to finding prey, and finding it quickly. The fish and krill that Adélie penguins pursue are often in just one school of fish, which they keep revisiting. If the penguins wait too long to catch their breath before diving again, their meal may have swum away or competitors may have eaten it. Then they must search for another school, which takes time and energy. If Adélie penguins are to be successful, efficient swimming and foraging skills are essential. more> http://tinyurl.com/bzrkcjw