138 PROF. W. J. DAKIN : EXPEDITION TO THE 



The Abrolhos Islands are favourite nesting places of sea-birds, the chief 

 breeding season being about the months of October and November. During 

 these months enormous numbers of Noddy Terns, Sooty Terns, and Lesser 

 Noddies frequent certain islets and the bushes are covered with their nests. 

 They rise in hundreds as one passes across the islets, although many stop in 

 their nests and refuse to budge unless pushed off. Wherever the coral 

 surface is covered with deposits of sand, etc. the excavations of Mutton- 

 birds abound. One falls through into them at every other step. As might 

 well be imagined, vast accumulations of guano have been formed on the 

 Abrolhos and this was removed on a large scale in the early nineties. 

 Wooden jetties were built and long trackways put down on the Wallaby 

 Islands. Moderately sized vessels called for the fertiliser, which was shipped 

 out of the State. Up to 1898 the records show that 55,000 tons of guano 

 had been excavated and exported. The work is still carried on during the 

 summer months by Mr. Fallowfield of Greraldton, who has the concession 

 from the Government for this purpose, but the amount now shifted is small 

 indeed compared with that of earlier days and it is not allowed to be 

 exported out of the State. Tbe guano deposits have covered the coral 

 surfaces of the islands with a layer a foot or more in thickness. The first 

 step in tbe process of collecting consists in the removal of all plant-growths 

 from the area being worked. Large loose coral blocks are then picked out of 

 it and stacked, and the rest is shovelled away and screened so that all the 

 small stones are removed. The residue is trucked to the jetty and bagged for 

 shipment to the coast. When the guano deposits are removed in this way, 

 the material is stripped so that the limestone surface of the island is 

 exposed. This is often quite flat and smooth, for the action of the rain, 

 the guano deposits, and the coral has resulted in a compact and rather 

 hard surface limestone. Tbe appearance of such an island afterwards is 

 often curious. The surface is brushed clean of all sand and deposit, whilst 

 Walls appear to have been constructed in all directions — they represent the 

 stacked coral blocks picked out of the guano. 



The invasion of the islands by guano workers has had an appreciable 

 effect upon the land flora, which consists almost entirely of xerophytic and 

 halophytio shrubs, and many of the plants have been introduced from the 

 mainland. So far as the fauna is concerned the guano workers do not seem 

 to have affected it very much, if at all, except that rats became a plague on 

 liat Island and cats were introduced to keep down the pest. The rats no 

 longer exist, but a few cats occur in a wild state and probably have a very 

 happy time during the nesting season of the terns. 



In concluding this brief general description, it maybe pointed out that any 

 expedition visiting the Abrolhos Islands has not only to carry full supplies 

 of provisions, but also fresh water. All the water used by the guano 

 workers has to be carried in tanks from Geraldton and is then laboriously 

 bailed out with kerosene tins and stored in small tanks. In the rainy 



