By its very nature, evolution is a long drawn out process. While it can be easily observed in the lab using organisms with short generation times like bacteria and fruit flies, seeing it happen in the wild with animals that live for much longer is far trickier.
But by using a long-term study of one population of penguins, researchers have been able to do just this, documenting natural selection acting on the birds, something which has only been achieved for a bird species once before.
“We know that evolution occurs – that species change,” explained the University of Washington’s Dee Boersma, co-author of the study published in the journal The Auk. “But to see this process in long-lived animals you have to look at generations of individuals, track how traits are inherited and detect selection at work.”
Boersma has been focusing on a single colony of Magellanic penguins in South America, spending 34 years documenting their lifespan, reproduction, and behavior.
Found along the coast on the tip of South America, the Magellanic penguin (Spheniscus magellanicus) nest in large colonies of up 500,000 individuals. But it’s their tendency to stick with one partner during breeding season, and return to the same beach each year that means Boersma has been able to follow individual birds over a period of decades, tracking their physical characteristics as well as keeping detailed notes on their offspring and their looks.
The penguins of the Punta Tombo colongy, Argentina. Dee Boersma