no. 3605 SEABIRDS — GILL 23 



Although many of the species encountered by Rand below 30° S 

 were the same as we found, there were several important differences. 

 Conspicuous by their absence on our March-April cruise were Cape 

 pigeons (Daption capense) which were the "most abundant of small 

 petrels" on his cruise in June-July. Also, on a previous cruise of 

 the Anton Bruun through these latitudes in September (,1963) Cape 

 pigeons were common (P. Willis, pers. comm.). On the other hand, 

 Rand saw few white-chinned petrels (Procellaria aequinoctialis) except 

 near the African coast, whereas in March and April this was a pre- 

 dominant species at our southern stations. Similarly, the soft- 

 plumaged petrel {Pterodroma mollis), which was a common species 

 at our stations, was not even recorded by Rand. It is unfortunate 

 that so few detailed reports of seabird species and numbers are 

 available for this region as there seem to be marked seasonal fluctua- 

 tions in the composition, distribution, and perhaps size of its seabird 

 community. Some of these may be related only to reduced pelagic 

 activity during the breeding season but others may be correlated 

 with seasonal changes in productivity. Also interesting would be an 

 elucidation of the subtropical convergence's role in limiting seabird 

 distribution. 



