Do Penguins Share?

Often, when several species living and competing for food in one location, they will employ different methods of resource partitioning in order to reduce competition for specific resources.

Researchers from the University of Tierra del Fuego in Argentina and Louisiana State University in the United States have recently asked the question above; focusing on local populations of Rockhopper and Magellanic penguins in Argentina coexist while competing for the same resources. 

Magellanic Pengin (Spheniscus magellanicus) and Southern Rockerhopper Penguin (Eudyptes chrysocome), respectively.

In theory, in order to successfully coexist in such close proximity to one another, these two species should be differentiating their diets in order to avoid direct competition for food. So, the objective of this study was to determine exactly how Rockhopper and Magellanic penguins differ in foraging ecology. 

In order to determine this, the researches used GPS trackers to record where exactly the penguins were diving, how long they were diving, and how deep they went. To determine what exactly they were eating, and at what level of the trophic level they were feeding on, isotope analysis provided from blood samples was used to take a closer look at the penguins’ diets. 

So what exactly were these penguins up to? Well, the Rockhopper penguins were feeding at much greater depths, and father offshore than their Magellanic counterparts. They also fed at a lower trophic level, so that the birds weren’t going after the exact same prey. The Rockhoppers also displayed differences between sexes in foraging activity. Males, who are most often larger than females, tended to dive deeper in their pursuit of prey. This not only reduces competition between species, but also reduces competition between males and females of the same species. What the researchers did not expect, however, is that there were no differences in male and female Magellanic foraging ecology. This was perhaps do to their smaller population size than the Rockhoppers.

In all, this is study a wonderful example of how animals modify their foraging behaviors in order to occupy specific niches, and reduce interspecies competition

Click here to read the complete findings of this paper.