They are called "Rockhopper penguins" because they hop from rock to rock.
They are the most aggressive of penguins; they will attack intruders with gusto, even jumping up to fasten on to a sleve and holding on furiously.
The rookeries are formed on rocky coatline. Two bluish-white eggs laid in a nest of pebbles or grass (acording to terrain). The nests are often in caves or crevices, or on open terraces. The breeding schedule varies according to location.
There are an estimated 1,882,000 pairs of Rockhopper penguins. The population is considered "vulnerable" by the World Conservation Union.
At one time Rockhoppers and other penguins were hunted for their oil. Today, all species are protected.