12 RUDOLF SÖDERBERG, STUDIES OF THE BIRDS IN NORTH WEST AUSTRALIA. 
The outset of the rainy season and its effect on the animal-life. 
It is not possible to give a description of the bird-life in those regions without 
at the same time emphasizing the all-changing importance of the outset of the rainy 
season (viz. the summer) has for the animal world as well as for the vegetable world. 
Certainly nowhere in the warm belts of the Earth can one observe a greater effect 
on the bird-world from the volumes of water in the rainy season then in the hot, 
dry savanna-woods of Australia. Without being as bare as the desert, but, on the 
other hand, without having anything like profuse vegetation, this type of country 
is nevertheless so far favoured as to be able to give shelter to a bird-fauna thatis astonish- 
ingly rich and varied considering of the uniformity of the natural features. It is 
the lack of water that drives the birds to leave large stretches of ground empty and 
unoccupied during most of the months of the year. But when the rain has brought 
moisture and the creeks and the small scattered reservoirs, without outlet, that are 
called billabongs in Kimberley, are filled with water, the flocks of birds come to 
the desolate regions and the natural features are completely altered, also through 
the awaking of lower animals. In a description of the birds in relation to the 
landscape it is therefore necessary to give a further account of those conditions. 
During my sojourn in Mowla Downs I also had the best opportunity to learn 
to know the character of the animal life before and after the rainy season. It was 
in a region where the natural features of the north-west Australian savanna were 
more typical than I have found them in any other place in Kimberley. During the 
days immediately succeeding my arrival at Mowla Downs the torrid season was still 
reigning there. The bird-life presented the same characteristics as at Fitzroy river. 
Greater and smaller flocks of birds were struggling about or dwelling in the neighbour- 
hood of the few water-pools which were found there. It ought, however, to be 
mentioned, that even there I found breeding birds, viz. birds living in pairs, thus 
not having waited for the outset of the rainy season. 
On the 18th of Nov. a slight cloud-formation appeared and a fine drizzling 
rain began to fall. On the following day dark, thick staccus-clouds were seen flocking 
together on the horizon. Soon the strong sunshine was moderated and extremely 
violent gusts of wind followed. The sand was whirled up like elouds and was swept 
forward along the ground. All the landscape was finally wrapped in sand-whirls which 
had the character of cyclones, mounting spirally like a fume, being torn up and 
dispersed again. At last the clouds discharged themselves in an enormously violent 
thunder-storm accompanied by a veritable tropical torrent of rain. This first out- 
burst died down towards the evening and in the zenith a blue spot appeared sur- 
rounded with mighty masses of clouds. After midnight the storm, however, rose again 
and a new deluge overflowed the land. It was this storm, of which only the fringe 
reached us, that burst over the little town of Broome on the coast (lying on the 
same degree of latitude that we were travelling on). With raging fury it swept over 
these parts and most of the galvanized iron houses in the town were blown down. 
