Bulletin 35 - July 1988: Seabirds


by Dr. W.R.P. Bourne

(Notes from a talk presented to the Dubai Natural History Group at the Metropolitan Hotel on January 31st 1988.)

Dr. Bourne, who has spent much of his recent time in the sea areas of the UAE and Oman, commenced by outlining a process known as upwelling. This occurs when winds blowing from land drive the surface water out to sea, causing an upward circulation of lower seawater and bringing nutrients to the surface. This in turn brings the fish closer to the surface to feed. From July to November, upwelling occurs along the South Arabian coast.

Summer visitors at sea during this time are the shearwaters and petrels. The Wedge-tailed shearwater Puffinus pacificus and Audubonís or Persian shearwater P. líherminieri persicus are seen then, though non-breeding birds may be seen throughout the year. They probably breed on offshore islands. Jouaninís petrel Bulwedria fallax, which was only described in 1955 (having no doubt been confused with similar species previously) feeds on squid. Its breeding sites are not known, but could be in the southern Arabian deserts. Seabirds feed on many fish species but each species of bird prefers a particular species of fish. Masked or Blue-faced boobies Sula dactylatra feed on flying fish.

In winter, upwelling occurs along the coast of the Gulf of Oman. Phalaropes tend to replace petrels, feeding on small marine life. They feed in flocks resting on the sea, with Red-necked phalarope Phalaropus lobatus being the more numerous. Persian shearwaters, which are divers, Black-headed gulls Larus ridibundus, White-cheeked terns Sterna repressa and Common terns, a collective name for both Arctic S. paradisaea and Common terns S. hirundo when separation is difficult, are seen in large numbers. It should be noted that nobody seems to have positively identified the Arctic tern in Arabia yet.

Inside the Strait of Hormuz, fish shoals move south in November and several Skua species are then seen; Long-tailed Stercorarius longicaudus rarely, but Arctic S. parasiticus and Pomarine S. pomarinus one or two a day. Black-headed gulls feed at sea but both move north for summer breeding. Lesser black-back gulls L. fuscus, which nest in Siberia, Great black-headed gulls L. ichthyaetus and Herring Gulls L. argentatus, which nest on the Black and Caspian Seas respectively, are also present. The Herring gulls seen inshore with yellow legs are different from the Armenian representative seen offshore. The latter winters at sea in the central Gulf and has a black band around the bill that sometimes obscures the red spot. The bill and head are smaller and they nest in the mountains to the north.

Dr. Bourne then shows some slides of Socotra cormorants, which breed on some of the offshore islands. The breeding season was almost over in December but there were still nests with eggs and all sizes of chicks. It is becoming increasingly important to leave some undisturbed breeding habitats, as this species, Phalacrocorax nigrogularis is only found around the Gulf and Southern Arabia and should be protected.


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