Estado poblacional, ecología y conservación del Petrel Gigante del Sur (Macronectes giganteus) en Argentina

the southern giant petrel (macronectes giganteus) is a pelagic seabird considered vulnerable with a circumpolar distribution restricted to the southern hemisphere. it is the only representative of procellariiforms breeding at the argentine coast (with the exception of the malvinas islands). in argentina, its nesting sites are confined to two colonies in the chubut province (arce island and gran robredo island) and two colonies in the staten island (observatorio island and península lópez). the breeding population size is estimated in 2600 pairs, 90% belonging to the colonies in chubut . the laying period (clutch size: one) starts in late october and the first eggs hatch during the last week of december. the fledgling period goes from late march to late april. southern giant petrel's diet is composed principally by penguins and cephalopods (mainly squid), and rests of marine mammals, fish and decapods. marine debris is also an important component of the diet. during the breeding period, feeding areas are located at the break shelf, middle shelf and coastal areas, with a clear spatial segregation between sexes. foraging areas also overlap with fisheries targeting on shrimp, squid and hake. the survey of population numbers and basic breeding parameters, together with the knowledge of behaviour-at-sea and the determination of the foraging areas of the southern giant petrel, constitute a primary tool to develop management and conservation plans for their populations.