THE BIRDS OF AUSTRALIA. 
as one variable species. In habitat both are the same ; flight, gait, mode of 
hunting for food, and the food itself are of the same kind. . . The difference 
appears to be in the plumage markings ; possibly too, in warble and tempera- 
ment, varying with the area. . . The warble of the ‘ Black-back ’ consists 
of about twelve distinct syllables, and is finished with an indescribable, 
delightful jubilant note. In every instance the female commences the warble, 
the male falling in at the last note, but holding it out longer than the female. 
The ‘ W hite-back 5 rarely indulges in a song, rendering it in a less musical 
style, and only in a chorus. The syllables are fewer and shorter. The last 
note is finished with a sharp piping ‘ Coo-oo,’ the emphasis being put on the 
‘ Coo,’ whereas the ‘ Black-back’s ’ last note is a distinct ‘ Croo-oo-oo,’ the 
stress being placed upon the c Croo ’ and the last ‘ coo.’ This accentuation 
is, however, peculiar to the male bird only. In temperament the ‘ White- 
back ’ appears to be more savage than the ‘ Black-back.’ In breeding time 
the ‘ White-back ’ will attack almost any living thing of large dimensions, 
the ‘ Black-back ’ rarely interfering with anybody.” Then followed a complete 
series of observations detailing plumage changes from nestling to adult. 
Mr. Tom Carter has written : “ Gymnorhina dorsalis is generally distributed 
through the south-west of West Australia, extending, along the coastal areas 
as far north as the Murchison River (about Lat. South 28°). There were several 
forests of the heavily timbered extreme south-west corner where these birds 
did not occur in the earlier years (1886-1896), notably areas of large Jarrah 
timber ( Eucalyptus marginata), which forests are very dark and gloomy, and 
usually devoid of bird life to a very great extent, and the Magpies prefer more 
open country and sunlight. An old friend of mine, a pioneer of the Vasse 
district, pointed out to me that Magpies were fairly common on the east side 
of the Carbadup River (some distance south-west of the Vasse River), but 
were not seen on the west side, where the Jarrah was large and dense. This 
was a fact that I personally confirmed in the course of driving with him, on 
several occasions, across the Carbadup River to the Margaret River on the 
coast, where my friend also had land. Several times my friend took young 
Magpies with him to his house on the Margaret River and let them free, but 
for many years they disappeared in the course of a fev r days, but eventually, 
as the coastal country became more settled and clearings were made in the 
dense forests, the birds remained and increased. In February, 1910, when 
travelling in the mail coach between the Blackwood and Warren Rivers, the 
driver, who had travelled the track for many years, pointed out some Magpies 
to me at a certain spot, and said it was the first time he had ever seen any 
there. This species was more numerous about Broome Hill than any other part 
of my observations. When driving along the roads, some of these birds were 
358 
