MIGRATION OF BIRDS. 157 



were widely branched, low and umbrageous, and 

 matted with underwood and creepers. The whole 

 aspect of the vegetation was totally different from 

 that of Australia. 



While we were in this neighbourhood, about the 

 end of February, great flocks of the bea-eater, which 

 is common in Australia (merops ornatus), were 

 continually passing to the northward. The white 

 pigeons, also (Carpophaga luctuosa), were going in 

 the same direction in numerous small flocks, and in 

 March all the pigeons left in the islands were young 

 ones. The bee-eaters go as far to the southward as 

 Sydney during the summer of New South Wales, 

 but we never saw the white pigeons much to the 

 southward of Torres Strait. In September, 1844, 

 they were coming thickly from the northward to 

 Endeavour Strait, and they seem to return in 

 March. What can be the reason of this migration ? 

 In these latitudes it is evident that mere temperature 

 cannot be the cause of it, although the variation 

 of the seasons for different fruits or insects may. I 

 had afterwards strong reasons for suspecting that 

 even on the opposite sides of so small a space as 

 Torres Strait, not more than 1^0 miles, the seasons 

 are totally different : that the wet season prevails in 

 New Guinea between March and October, which, on 

 the north of Australia, is the driest part of the year ; 

 while from October to March, when most rain falls 

 in Australia, it is probable that the south coast of 

 New Guinea has its driest weather. 



