320 A HISTORY OF BIRDS 



years ago to eat the fruit-destroying caterpillars. But they 

 soon transferred their attentions to the fruit, and have multiplied 

 exceedingly. Further, they have taken to evicting Kingfishers, 

 Tree-swallows and Tree-creepers from their nests, and it is 

 possible, within a few years, may even exterminate these 

 feebler species. In Inaccessible Island, one of the Tristan Da 

 Cunha group, Moseley found that feral pigs had well-nigh 

 exterminated the Penguin {Catarrhactes chrysocome), which 

 formerly abounded there, only a few remaining at one corner 

 of the island, and these had contrived to survive by nesting in 

 holes, out of reach of the pigs — a habit of nidification not 

 practised by this' species elsewhere. Plenteous remains of these 

 Penguins testified to their former abundance. 



The great Skua, a predaceous Gull, is a bird which adds 

 considerably to the struggle for existence among the birds 

 amid which it dwells. Not only does it persistently — like all 

 its relatives — pursue all other Gulls coming in from the sea, and 

 compel them to disgorge their latest meal, but levies a heavy 

 toll on the smaller species of Petrels, either dragging them from 

 their burrows, or seizing them as they leave at twilight for the 

 fishing grounds. It is exceedingly probable indeed that the 

 nocturnal habits of these latter birds have been adopted as a 

 more or less effectual means of escape from persecution of this 

 kind. For, as is well known, most of the Petrels do not emerge 

 from their underground retreats until their neighbours have 

 retired to rest. During the breeding seasons these predatory 

 Gulls work great havoc among the eggs and nestlings of every 

 species within their range. In the desolate wilds of the Ant- 

 arctic the same policy of rapine is pursued by McCormick's 

 Skua, a species not easily distinguishable from the Great Skua 

 of the northern hemisphere. This bird wages a ruthless war 

 on the great hordes of Adeli^ Penguins which contrive to find 

 in these icy regions a congenial home. Dr. E. A. Wilson, the 

 naturalist to the British Antarctic expedition of 1901, vividly 

 describes the audacity and. cunning which these marauders 

 display in seizing first the eggs and later the young birds. 

 With an almost unlimited supply of victims so easily procured, 

 this Skua would doubtless soon multiply enormously — though 

 this increase would inevitably be ultimately reduced, in pro- 

 portion as the Penguins decreased — but for the fact that they 



