TRISTAN DA CUNHA. 125 



The pigs now remaining are mostly boars : they are very 

 hairy and have long tusks. The hogs are fierce, and one of the 

 Germans told me that one once regularly hunted him, as if to 

 attempt to kill him for food. The pigs feed mainly on birds 

 and their eggs, but eat also the roots of the tussock and wild 

 celery; they have nearly exterminated a penguin rookery on 

 the south side of the island, but a few penguins remain, who 

 have learnt to build in holes under stones, where the pigs 

 cannot reach them. 



This fact is curious, as showing how easily circumstances 

 may arise, such, that in an island even so small as Inaccesible, 

 one colony of birds may develop a totally new habit, whilst 

 other colonies of the same species preserve their original cus- 

 toms. And yet how strong is the tendency in birds to preserve 

 their habits ! I know of no more striking instance of this than 

 the fact that the Apteryx of New Zealand (A. Australis) con- 

 siders it necessary to put as much of its head as it can under its 

 rudiment of a wing, when it goes to sleep.* 



The pigs cannot get down the cliffs to the rookeries on the 

 north side of the island. 



One penguin at the Falkland Islands (Spheniscus Magel- 

 lanicus) regularly nests in burrows, sometimes twenty feet long. 

 Another species of the same genus (Spheniscus minor), breeds in 

 neat holes burrowed in sandbanks, at New Zealand.f 



On the beach are large banks of seaweed, but as at Tristan 

 the heavy surf so batters the weeds, that it is difficult to find a 

 serviceable specimen. An Octopus is very common amongst 

 the stones, about the edge of the surf. I caught several at- 

 tracted by the washing of the penguins' flesh and skins in the 

 water. A Chiton, Patella and Buccinum are also common about 

 the shore, as at Tristan. 



All night long the penguins on shore in the rookery kept up 

 an incessant screaming, no doubt lamenting the terrible invasion 

 to which they had been subjected. The sound at a distance was 

 not unlike that which one hears from tree-frogs in the south of 



* T. H. Potts, "On the Birds of New Zealand," Vol. II, 1869, p. 75. 

 Trans. N. Z. Institute. 



t T. H. Potts, Ibid., Vol. V, 1872, p. 186. 



