Primarily, there are three birds that prey on penguins. They do not prey on adult penguins; however, their interests remain fixated on those newly hatched chicks or eggs. They all have an advantage over penguins. They can fly. Some work in teams, others just work by themselves. Some discussion mentions the petrel as a predator of penguins; I don't know how much they contribute to penguin decline. I think they mostly scavenge the remains of penguins left behind by sea lions and orcas. (Please close small window when finished.)

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    The Brown and McCormick skuas, related to the various species of gulls, are no more than nuisances to adult penguins. However, these birds pose a potential threat to the unguarded nest or chicks. An experienced adult has relatively no problem warding off these birds of prey.

    Skuas are also observed to prey upon the weak and old of the penguin colonies as well. But more often, skuas clean off the skeletons of dead penguins that have washed ashore after being ravaged by much larger mammalian predators.

    Skuas are also territorial birds and their territories include about 10,000 penguins per bird. Related skuas often share territories and work in pairs - one distracting the adult while the other attacks the chicks. Whether the benefits of this group attack are shared equally among skuas, I do not know. Skuas are the most effective of avian predators on penguins.

    Sheathbills look like menacing hens rather than the scavengers that they are. Their bald faces suggest that preying upon the dead remains of chicks and adults is their primary role. Sheathbills seem to have no fear about prowling around penguin colonies. On other occasions, sheathbills interfere with the feeding of penguin young as well. Sheathbills have been observed to disturb adults to the point where food is dropped before feeding chicks. This is typically accomplished by the focal bird when it strategically displaces the chick before the parent finishes complete regurgitation. Food is dropped onto the ground and the result is a happy sheathbill and a hungry penguin chick.

    With the exception of one other bird, the sheathbill is the only Antarctic/ Subantarctic avian species without webbed feet.

    See another picture of a sheathbill.

    The predation effects of the Austral caracara is negligible. They have been observed to prey upon Rockhopper nests in the Falklands and on West Point Island. Caracaras typically wait for nests to be left unattended before snatching chicks in a hawk-like manner. Despite the fact that Rockhoppers typically fledge only one chick per breeding season, the caracara does not take enough of them to pose an ecological threat.

    There are other species of caracaras, but the common caracara, or Johnny Rook, is the one that addresses the concerns of the penguin. You may have seen other more brightly colored caracaras out there.