^°\S^^] -MAC(;iLlJ\k AV, .lustralia,, Pcliam. 163 



'Ihe Uaiiing is usually a runnin^^ stream, hut may in very dry 

 limes be reduced to a series of waterholes. Small floods, which 

 do not rise to the top of the channel, usually occur every two 

 or three years. Floods which overflow the banks and fill the 

 lower flats to a greater or less extent occur at longer intervals. 

 Exceptional floods which cover all the flats and run the out- 

 lying channels to the filling of the larger lakes only happen once 

 or twice in an ordinary lifetime. Such large floods took place 

 in 1864, 1870, 1890 and in 1921. and it is of the nesting of the 

 Pelican (Pclicaiuis conspicillotus ) during the last big floofl that 

 these notes are mostly concerned. 



Boolaboolka Lake, the terminal one of the series of lakes filled 

 by the Talyawalka, has not been filled since 1890. Last year 

 water poured into it for three months, but did not fill it, in spite 

 of the fact that most of the others had been filled tweh'e months 

 before. 



Whenever a flood of sufficient extent to overflow the banks 

 and to isolate numbers of trees and lignum bushes occurs, water- 

 fowl of many kinds start to nest, Swans, Ducks, Coots, and 

 W aterhens being the earliest, with wading birds, such as 

 Herons, Spoonbills, and Ibises. Pelicans, Darters, and Cor- 

 morants do not nest unless other special conditions obtain, and 

 these have relation to food supply and protection. 



When the river is low or reduced to a series of holes, the 

 smaller and naturally more prolific of its fish fauna have their 

 numbers kept in check by the Cod, from which dominant species 

 they have little or no chance of escape. Their ova and small 

 fry are also more easily preyed upon by crayfish, birds and 

 tinile. 



When, however, the waters spread out over large flats and 

 lake areas, these adverse conditions are removed, and these 

 species increase enormously, and one finds that Pelicans, Darters 

 and Cormorants do not attempt to nest until these areas have 

 been filled for tw^elve months or more, and the fish have been 

 given time to multiply. 



The Cormorants and Darters choose trees standing in water, 

 on which to place their nests ; the bulkier Pelican, however, re- 

 quires an island where its eggs may be incubated and its young 

 reared free from molestation by marauding animals for a period 

 of from 5 to 6 months or more. At Boolaboolka these condi- 

 tions have not obtained since 1894, when the last breeding took 

 place. Last year it was the last lake to receive the flood waters 

 and then not in sufficient amount to form the required island. 



The last nesting of Pelicans in this district was at Cawndilla 

 in 1904. 



At Teryawynia Black Swans (Chenopis atrafa) nested freely 

 on some of the islands during the winter and early spring of 

 1921, but the Pelicans took charge of several islands isolated by 

 the flood waters at the end of the year, and have had possession 

 ever since. 



