THE VICTORIAN NATURALIST. 181 



birds were, came to the conclusion that the minimum number was 

 200,000. Of course, only one-half of the birds would be in the 

 swamp at one time, as. the other half would be away feeding, i No 

 illustration we could show would give much of an idea of the 

 number of birds or extent of the rookery, unless a photo, was 

 taken from a balloon or some such eminence, for even when a gun 

 was fired off only those in the immediate vicinity — say, of sixty 

 yards — would rise, and not even all those unless they caught 

 sight of the intruder ; they would then circle round at a consider- 

 able height up, but wOuld. soon settle again. The noise of the 

 wings of the birds as they flew past was similar to the rustling of 

 silk. The Ibis which first arrived started nesting in the middle 

 of the swamp, and as fresh arrivals came so they had to build on 

 the outskirts of those there before them, consequently the centre 

 nests would have fully fledged young ones in, while at the out- 

 skirts late arrivals were only building. 



On entering the swamp trodden-down Lignum bushes would 

 soon be met with, from which a few birds would fly away. Then 

 would be passed fresh nests built; with green twigs of Lignum, then 

 again nests with one egg in each, and as we proceeded two eggs 

 would be noticed in each nest, then three, the usual comple- 

 ment. Further still they would be found hatching, and as the eggs 

 hatch in the order they are laid, eggs and very young birds would 

 be noticed in the same nest. As we proceeded young in 

 different stages would be noticed, which, on being disturbed, leave 

 their nests and crowd up together, and readily climb over the 

 Lignum and take to the water if . approached too closely. They 

 then swim to neighbouring bushes, and, although i they are 

 not web-footed, they swim well and high. The parents feed 

 them by placing partially digested food in their mouths, 

 which food consists of grasshoppers, caterpillars, freshwater snails, 

 &c, and if the young birds are handled much they occasionally 

 eject the. food from their stomach. The contents of an average 

 crop of an adult bird contained by actual counting 2,410 young 

 grasshoppers, five freshwater snails, several, caterpillars, and some 

 coarse gravel, which, if you multiply by 200,000, brings up a big 

 total of 480,000,000 odd grasshoppers, as well as vast numbers 

 of caterpillars and snails, and also these latter are the host of 

 liver fluke, which sheep so easily get in certain damp localities ; 

 and one must remember that this is going on. every day, so, a 

 little idea can be formed of the immense utility these birds are in 

 destroying noxious, insects. . Then, again, the average number of 

 young is about 2 y 2 to each pair of parent birds, and the contents 

 of their stomach must reach an enormous total, as they all seemed 

 gorged with food. Grows, or rather the Australian . Ravens, 

 Gorone mistralis, occasionally eat the eggs and young of these 

 birds, but not often, as only four instances of it were noticed. 



