Southern rockhopper penguin may just be a colour morph of the macaroni penguin. Interbreeding with the macaroni penguin has been reported at Heard and Marion Islands, with three hybrids recorded there by a 1987-88 Australian National Antarctic Research Expedition. The southern rockhopper penguin group has a global population of roughly 1 million pairs. About two-thirds of the global population belongs to "E. c. chrysocome" which breeds on the Falkland Islands and on islands off Argentina and southern Chile. These include most significantly Isla de los Estados, the Ildefonso Islands, the Diego Ramírez Islands and Isla Noir. "E. c. filholi" breeds on the Prince
Rockhopper Exploration in production licences PL023, PL024, PL032 and PL033 covering approximately 3800 km. In 2005 it farmed into licences PL003 and PL004 operated by Desire Petroleum plc. In 2011, Rockhopper increased its share of PL004b from 7.5% to 60.0% and in PL004c from 7.5% to 25.0%. Licence PL004b contains an extension to the Sea Lion field as well as the Beverley, Casper and Casper South discoveries. The Rockhopper board comprises eight directors; a non-executive chairman, three executive directors and four non-executive directors, one of whom acts as senior independent director. Four of the non-executive directors are considered to be independent. The