20 RUDOLF SÖDERBERG, STUDIES OF THE BIRDS IN NORTH WEST AUSTRALIA. 
Australia the seasons are two, the one characterized by sporadic rains, the other by 
exceedingly dry weather, while the differences of temperature are comparatively small. 
The quick transitions do not allow a spring or an autumn moulting of short 
duration (even if such moulting exists), and it is therefore natural for the time of 
moulting as well as for that of breeding to be extended to a more or less unlimited 
extent during the time when the most favourable circumstances prevail, namely 
during the rainy season. 
Here it is especially remarkable that the group of birds which preeminently 
belong to the warmer countries of the earth, and in Australia is represented in so 
splendid a manner, namely by the parrots, show more pronounced adaptation to 
climatic circumstances in the above-mentioned respect than any others in North West 
Australia. 
One feature is universally prevalent, namely that these birds have one moulting 
time, which comes during the months of the rainy season. 
In the case of the great majority of the other birds it is a rule that the 
moulting begins at the time for the approching of the rains, or the summer, or else 
it may happen after incubation or breeding. In this case as well, especially if the 
time of moulting is spread indefinitely over the whole summer, there is with these birds 
something much more individual in the whole procedure than in the case of the 
birds in the northern hemisphere. Different specimens of a species are found to have 
hatched their young ones and entered upon the moulting at a time, when other (un- 
paired) birds are seen in a torn and old plumage, i. e. not moulting and with 
swollen genital organs. 
Besides, the individual trait shows itself also in the fact that the moulting in 
the same species does not always begin at the same parts of the plumage, a matter 
which, however, may be rather common to the birds in general, as far as we know. 
In the case of the young birds certain parts of the plumage may even some- 
times be left out during moulting, or the process may stop, and be continued in a 
suceceeding moulting. But it is to be noticed that new feathers of the character 
of the juvenal plumage also appear in the first moulting. Young birds, belonging 
to quite different species, have also been found moulting in the first instance during 
other periods than the adult bird, as in the month of May or even in July, about 
half a year after they have been born. 
In the case of some species there are two times for moulting. These seem, 
however, to be different for different species. Some have their first moulting time 
during the rainy season, the others in the middle of winter (then the quills or 
tail-feathers are not always cast). Others moult in the month of April (or May), 
i. e. shortly after the end of the rainy season, and a second time at the beginning 
of the same season (Oct.—Nov.). Possibly, however, it is more general for the 
' Australian migrating birds than for the stationary species. 
Malurus melanocephalus cruentatus, Melithreptus lunulatus subalbogularis and 
Lobivanellus miles were in typical moulting in the month of July. 
