The original park has subsequently been expanded to include the Woody Cape Nature Reserve that extends from the Sundays River mouth towards Alexandria and a marine reserve, which includes St. Croix Island and Bird Island, an important breeding habitat for gannets and penguins, not to mention a large variety of other marine life. Bird Island is home to the world's largest breeding colony of gannets - about 120,000 birds - and also hosts the second largest breeding colony of African penguins. This forms part of the plan to expand the 1,480 km² Addo National Elephant Park into a 3,600 km² Greater Addo Elephant National Park.