Description & Characteristics:
The Rockhopper penguins are small, aggressive, crested penguins (genus Eudyptes), so named because of the way they hop from boulder to boulder when moving around their rocky colonies. Rockhoppers are a sub-Antarctic species breeding at cool, southern localities such as Macquarie Island, the Falklands, Campbell Island, Tristan da Cunha, and the Antipodes. On some islands the populations have declined substantially and the species has just been upgraded to 'vulnerable' by the International union for the Conservation of Nature. Although there is as yet no consensus of opinion, three subspecies of Rockhopper have been recognized.
Rockhoppers have distinctive crest feathers on their heads, bright orange-red bills and tiny blood red eyes. Males and females are very similar in appearance, though males are larger. They are distinguished from the Macaroni penguin and other members of the crested species by their smaller size and the thin, vivid yellow tassels which extend along the sides of the brow but do not meet between the eyes. The top of the head has spiked black feathers. Like all penguins, Rockhopper have a big head, a short, thick neck, a streamlined shape, a short, wedge-shaped tail, and strong, stiff, flipper-like wings. For camouflage from predators, their underparts are mostly white, while the upperparts are blue-black.
Rockhoppers use their webbed feet and strong powerful flippers for swimming and pursuit diving after prey. They feed mostly upon lantern fish, small euphausiid crustaceans (mainly krill), and occasionally squid. Their exceptional hopping abilities are required to enter and emerge from the sea and to reach their rocky nesting sites.
Breeding during the summer months, mated Rockhopper pairs establish rocky burrows among tumbled boulders or on scree slopes of exposed shores. Female Rockhoppers will lay two eggs though the smaller, first-laid egg is often lost during incubation and even if retained, does not always hatch. Males and females take turns guarding and feeding the growing chick which fledges in March.
Rockhopper colonies are often relatively small compared with other penguin species but what they lack in size they make up for in noise. Fierce competition for nesting materials, mating partners, and territory all contribute to the cacaphony of sound at these sites. As well as vocalizing, these birds communicate by head shaking, head and flipper waving, bowing, gesturing and preening.
At sea, Rockhopper penguins are eaten by blue sharks, leopard seals and fur seals. On land, eggs and chicks are eaten by many birds, including skuas, petrels, and Kelp gulls.
Rockhoppers have an average life span of 10 years.
- Rockhopper penguins are the most widespread of thc crested penguins and also the smallest.
- In some localities Rockhopper numbers have decreased alarmingly due in part to disease, introduced species and possibly warming seas.
- 'Rockies' have a very loud cry called 'ecstatic vocalization', which is used to announce their presence, to attract a mate or to state their territory. Also, by shaking their heads they cause their yellow eyebrows to fly into a 'halo' in order to attract a mate.
- As in many penguin species, male Rockhoppers are capable of producing 'milk' from their digestive systems which they then regurgitate for their chicks when the female is away hunting for food.