Rockhoppers use species specific mating calls called 'ecstatic vocalisation' to attract their mate from previous years.

Statistics
Height: 55cm (21in), Weight: 2-3kg (4.5-6.5lb).

Physical description
They have a thick waterproof coat of feathers that is white on the underside of the bird and blue-black on the back. The head has bright yellow plumage on the brow with long feathers that extend outwards. They have tiny red eyes and an orange bill.

Distribution
Rockhoppers are found on islands in the southern oceans, such as the Falklands, and are found all round the sub-Antarctic islands. They leave their breeding colony in late summer and spend three to five months at sea.

Diet
The rockhopper.s diet is composed of krill but they will also eat other crustaceans, squid and, particularly in the north, fish. They find their food, when breeding, during daily trips to the sea.

Behaviour
Rockhoppers can be aggressive and use a loud cry to announce their presence, attract a mate and state their territory. They also shake their heads causing their yellow plumage to form a halo when attracting a mate. When at rest they hide their heads under their wing. They like to live in high grasses and rocky areas of temperate grassland and coastal biomes.

Reproduction
They mate in large colonies in early spring or late summer (Oct-Apr) so the young are able to go to sea in mid-summer. Rockhoppers usually lay two eggs. Incubation is by both sexes and lasts almost five weeks with a creche forming at about three weeks and departure to sea seven weeks later.

Conservation status
Rockhoppers are classed as Vulnerable by the 2000 IUCN Red List of Threatened Species. There are possibly 3,500,000 pairs breeding with the majority in the Falklands.