Are Southern Giant Petrels a “fearful scourge” to penguins?

 
A Southern Giant Petrel with the carcass of a Northern Rockhopper Penguin Eudyples moseleyi, photograph by Peter Ryan (click here for publication)

Eric Wagner (Center for Ecosystem Sentinels, Department of Biology, University of Washington, Seattle, Washington, USA) and colleagues have published open access in the journal Ecology and Evolution on an observation of Southern Giant Petrels Macronectes giganteus attacking a Magellanic Penguin Spheniscus magellanicus.

The paper’s abstract follows:

“Southern giant petrels (Macronectes giganteus) are important consumers that range across the oceans throughout the southern hemisphere.  In Argentina, previous studies have shown they eat primarily pinnipeds and penguins, which they are assumed to scavenge, although there are occasional anecdotes of them attacking living penguins.  Here we describe a predation attempt by a trio of southern giant petrels on a molting adult Magellanic penguin (Spheniscus magellanicus) at the large colony at Punta Tombo, Argentina.  We relate giant petrel attendance patterns at the colony to the penguins' phenology, showing how giant petrel numbers rise with the increasing prevalence of vulnerable penguins.  We suggest that living penguins—both fledglings and adults—may constitute a more seasonally significant proportion of the giant petrel diet than previously assumed, and their capture may represent a specialized predation technique.”

Reference:

Wagner, E.L., Rebstock, G.A. & Boersma, P.D. 2024.  A fearful scourge to the penguin colonies: Southern giant petrel (Macronectes giganteus) predation on living Magellanic penguins (Spheniscus magellanicus) may be more common than assumed.  Ecology and Evolution. 2024;14:e11258.

17 May 2024