THE BIRDS OP AUSTRALIA. 
The movements and subspecies of this genus are not well known. The 
western form is differentiated from the eastern by size, but there seems to be 
httle variation of geographic significance in colour. The species has been 
commonly recorded from the islands to the North of Australia, but no series 
have been collected for comparison with southern birds. The wing-formation 
suggests power of long flight so that it is possible the northern birds do make 
migratory movements of some distance, but these would probably be hmited 
to certain lines so that the eastern and western races would never meet, 
however far the latter moved, though I do not suggest that they migrate beyond 
New Guinea. Facts are, however, scarce in this connection, the suggestion 
that they were migratory being sufficient for unfounded statements as to their 
migrations, though the hearing of the note seems the most noticeable item in 
the “records.” An eastern and western form are admitted. 
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