Southern Giant Petrel

As in all seabirds, southern giant petrels nest on land and feed at sea.  They nest in groups, but in most places, they do not form the extremely dense colonies characteristic of several other species of seabird.  This species prefers to nest on the ground rather than in trees or other vegetation and generally does not successfully mate until reaching an age of at least 10 years old.  Parents incubate the egg and care for the juvenile together, an investment approaching 200 days before the juvenile is ready to feed on its own. 

Southern giant petrels eat mostly invertebrates (krill, squid, etc.) or scavenge for dead and decaying matter.  They are particularly adept at following fishing vessels and preying on dead fish and/or invertebrates that the boats discard.  They also are occasionally accidentally drowned when they eat baited hooks in hook and line fisheries.  There is apparently segregation of feeding grounds between males and females, and males have been observed chasing females from scavenged carcasses of seals and other animals.

Though southern giant petrels have been accidentally captured in marine fisheries in the past, changes in fishing technique and technological advances have reduced those interactions.  Scientists believe the populations to be increasing in numbers and generally consider the southern giant petrel to be a species of least concern. 

Note on a closely related species:  The southern giant petrel is closely related to the Northern Giant Petrel (Macronectes halli).  These two species look very similar in appearance, and though their common names imply that they live in different places, their geographic ranges overlap almost fully.  Slight differences in range and very subtle differences in beak color are the only reliable way to tell these two sister species apart.