Climate Change Means Penguin Colonies Decline

  • Published on February 25th, 2009

magellenic penguins

Magellenic penguins living on the Punta Tombo peninsula, 110 kilometres south of Argentina, are having to swim up to 50 miles further to find food than they did ten years ago.

The vast distances that adult birds are travelling to feed themselves, and their chicks, is translating into failed breeding – the colony is a fifth smaller than it was twenty years ago. A major reason for the increased pressure put on the birds is global warming which has meant the food sources the penguins rely on have become variable. Ocean currents have altered, moving fish stocks away from the colony in some years and leading to the double-marathon extra journey that birds must make to find food. Magellenic penguins take it in turn to incubate eggs and care for chicks, so while one parent is away for days or even weeks, the other fasts until his or her return with regurgitated food for stay-at-home parent and hatchling. The longer journeys to forage for food add to the risk of parent or chick becoming too weak from lack of food to recover when a meal is finally presented.

Relocation, relocation, relocation – but no happy ending

Some birds that were originally tagged as part of the Punta Tombo colony are now nesting up to 250 miles further south, because food supplies are more plentiful there, and while it’s good news that the birds can relocate in this way, the new colonies are not in protected reserves, like Punta Tombo, so the birds are at much greater risk from human activity in their new homes. Relocating penguins are also predating on the Argentinian fleet’s anchovy fishing, meaning that more birds get fouled in fishing nets and die. Competition for food-stocks between fishermen and penguins may mean the new colonies are short-lived. Some fishermen are said to be calling for an organised cull of the penguins in their new homes.

Chicks die in rain puddles

In addition, unusual heavy rain in the breeding season is killing the hatchling penguins. In the past 25 years, Punta Tombo has only received two or more inches of rain five times between October and December, with three of those rainfalls happening during the past decade. This is a crucial time for eggs and chicks because the rain fills the small depressions that serve as nests and, because the small birds do not have their adult plumage, they are at risk of dying from cold. Eggs will not hatch if the water pools under them, so the changing weather pattern is also damaging the colony’s ability to thrive.

Image: Magellenic penguin and chick by lrargerich at Flickr under a creative commons licence

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