Over the years, we have conducted a number of studies on the ecology and behaviour of Falkland skuas, a subspecies of skua that is virtually endemic to these islands. We now have interesting information on the migratory habits, diet and demography of this species. Surprisingly, census work carried out in 2004 and 2009 revealed a sharp population decline, the cause of which is so far unknown.  The decline seems to be linked with a chronic low breeding success in the recent years and is consistent with a situation of virtually zero recruitment. The ultimate causes of the decline are, as yet, unknown. One possibility is that the sustained population growth of Striated Caracaras Phalcoboenus australis, (locally known as Johnny Rooks) a known competitor and predator (of chicks and eggs) of skuas, may be giving the skuas a hard time. Alternatively, there could be less prions Pachyptila belcheri available for the skuas to eat, and prions probably are the most important prey item at this site. Studies to investigate these and other possibilities are now under way.

The Falkland Skua (Catharacta antarctica antarctica) is a subspecies of the Brown Skua (Catharacta antarctica) and its essentially confined to the Falkland/Malvinas Islands, also occurring in very small numbers on the Southeast coast of Argentina. New Island is, as far as it is known, the most important breeding site for this species in the Falkland’s archipelago. Being a migratory seabird, Falkland skuas live a pelagic life during winter, returning to the Falklands/Malvinas to the breeding season. On New Island, birds arrive on the second fortnight of October and remain there until late March. Highly predatory, Falkland skua diet consists mainly of burrow-nesting prions, barnacles and other crustaceans, but they also feed on fish and on eggs and chicks of penguins and albatrosses. During the breeding season, when pairs nest in the vicinity of seabird colonies, they can also defend feeding territories. In the last decades, skua populations have shown very contrasting demographic trends in their different breeding grounds. The most common causes of these oscillations include human disturbance, habitat destruction, bad weather, control or introduction of exotic mammals, changes in prey populations and in fisheries bycatch.