INTRODUCTION, XIX 
species of birds appear to entirely forsake the part of the country in which they have been accustomed to 
dwell, and to betake themselves to some distant locality, where they remain for five or ten years, or even 
for a longer period, and whence they as suddenly disappear as they had arrived. Some remarkable 
instances of this kind came under my own observation. The beautiful little warbling Grass Parrakeet 
(Melopsittacus undulatus), which, prior to 1838, was so rare in the southern parts of Australia that only 
a single example had been sent to Europe, arrived in that year in such countless multitudes on the 
Liverpool plains, that I could have procured any number of specimens, and more than once their delicate 
bodies formed an excellent article of food for myself and party. The Mymphicus Nove-Hollandia forms 
another case in point, and the Harlequin Bronze-winged Pigeon (Peristera histrionica) a third; this 
latter bird occurred in such numbers on the plains near the Namoi in 1839, that eight fell to a single 
discharge of my gun ; both the settlers and natives assured me that they had suddenly arrived, and that they 
had never before been seen in that part of the country. ‘The aborigines who were with me, and of whom I 
must speak in the highest praise, for the readiness with which they rendered me their assistance, affirmed, 
upon learning the nature of my pursuits, that they had come to meet me. The Zribonyw ventralis may be 
cited as another species whose movements are influenced by the same law. This bird visited the colony of 
Swan River in 1833, and that of South Australia in 1840, in such countless myriads, that whole fields of 
corn were trodden down and destroyed in a single night; and even the streets and gardens of Adelaide 
were, according to Captain Sturt, alive with them, 
If we compare the ormthology of Australia with that of any other country in similar jatitudes and of 
the same extent, we shall find that it fully equals, if it does not exceed them all, in the number of species it 
comprises ; and those parts of the country that are still unexplored doubtless contain many yet to be added 
to the list of its Fauna. 
In the course of the present work it will be found that I have given a wide range of habitat to 
some of the species, and that I have at the same time pointed out slight variations, not amounting to a 
specific difference, in individuals from different localities, This difference I am unable to account for, 
Ido not believe the birds to be distinct species, but am inclined to regard them as varieties or races of 
the same species, modified by the character of the situations they frequent. I may mention some curious 
instances in point: the dréamus sordidus is a migratory bird in Van Diemen’s Land, and is partially 
stationary in New South Wales, yet all the examples procured in the former country are the largest 
and most vigorous, which we should naturally attribute to the excess of food afforded by its more humid 
climate; but precisely the reverse of this occurs with regard to the Graucalus parvirostris, which is also a 
migratory bird in Van Diemen’s Land, and examples of which, killed in that island, are much more feeble 
and diminutive than the Graucali obtained m New South Wales. The Halcyon sanctus, again, whose 
distribution is universal in Australia, varies somewhat in size in every colony, still not sufficiently so as to 
afford any tangible specifie characters. 
Upon taking a general view of the Australian ornithology, we find no species of Vulture, only one 
typical Eagle, and indeed a remarkable deficiency in the number of the species of its birds of prey, with 
the exception of the nocturnal Owls, emong which the members of the restricted genus Sériz are more 
numerous than in any other part of the world; a circumstance which is probably attributable to the great 
abundance of small nocturnal quadrupeds. 
