418 BIRDS OF AUSTRALIA. 



beneath the branch, giving it the appearance of a much larger 

 structure than the reahty ; the nests and the branches of the 

 trees are completely whitened with the excrement of the bird, 

 the disagreeable and sickly odour of which is perceptible at a 

 considerable distance. South Island, Houtmann's Abrolhos, 

 appears to be the only one resorted to for the purpose of nidi- 

 fication ; for although large mangroves occur on others of the 

 neighbouring islands, it was not observed on any of them. 

 " I have seen many vast flocks of birds," says Gilbert, " but 

 I confess I was not at all prepared for the surprise I expe- 

 rienced in witnessing the amazing clouds, literally speaking, 

 of these birds when congregating in the evening while they 

 had their young to feed. During their alternate departure 

 and return with food they presented a most singular appear- 

 ance. From their breeding-place to the outer reef, beyond 

 the smooth water, the distance is four miles ; and over this 

 space the numbers constantly passing were in such close 

 array that they formed one continuous and unbroken line. 

 After the young birds were able to accompany their parents, 

 T observed that they all left the breeding- or roosting- 

 place in the morning and did not again return until even- 

 ing, the first-comers apparently awaiting the arrival of the 

 last before finally roosting for the night. It is when thus 

 assembling that their immense numbers strike you with 

 astonishment. Even those who have witnessed the vast 

 flights of the Passenger Pigeon, so vividly described by Au- 

 dubon, could hardly avoid expressing surprise at seeing the 

 multitudes of these birds which at sunset move in one dense 

 mass over and around the roosting-place, when the noise of 

 the old birds, the quack and the piping whistle of the young 

 ones, are almost deafening. Like its near ally, it commences 

 the task of incubation in December, and lays but a single egg : 

 while sitting on which, or tending its young, it is very easily 

 caught, as it will suffer itself to be taken off the nest rather 

 than quit it. It forms an excellent article of food, and' several 



