King penguins don’t like to space themselves too close or or too far from their neighbors during breeding season. These penguins don’t build nests, instead cradling their eggs on the top of their feet during incubation. King penguins also tend to be territorial, pecking at other penguins that come too close to them. At the same time, these penguins need to form in colonies for protection against predators. Researchers have found that this allows them to be fluid, acting almost like liquid in how these birds space themselves out in colonies.
In a newly published study, researchers looked at the structural order of King penguins during the early breeding cycle where egg incubation is occurring. The researchers used aerial imagery taken over two colonies on Crozet and Kerguelen islands over several years in order to map out the spatial positions of thousands of penguins.
Researchers found that a balance between territorial pecking and a need to form in colonies as protection against predators resembled a a Lennard-Jones type potential, a 2D liquid of particles where forces both repel and attract. “This liquid state is a compromise between density—or how compact the colony is—and flexibility, which allows the colony to adapt to both internal and external changes,” explains senior author Daniel Zitterbart, a physicist at Woods Hole Oceanographic Institute (WHOI) and adjunct scientist at the University of Erlangen-Nuernberg.
This video (taken by: Céline Le Bohec (Video courtesy © IPEV, Programs no. 137 and 354) shows how a disturbance, such as this elephant seal, makes the King penguins move and then reestablish their careful spatial structure.
Richard Gerum and Sebastian Richter and Ben Fabry and Céline Le Bohec and Francesco Bonadonna and Anna Nesterova and Daniel P Zitterbart. (2018). Structural organisation and dynamics in king penguin colonies. Journal of Physics D: Applied Physics, 51(16), 164004.