8 SEA-BIRDS 



The Atlantic thus is a mosaic, not a homogeneous area. Each 

 patch in the mosaic is characterised by some pecuharity of climate. 

 In practically all areas the water, the prime constituent, is in a state of 

 continual movement. The fortunes and distribution of our sea-birds 

 depend on this environment, so continually in turmoil. We must beat 

 the bounds, then, of the North Atlantic and discover how our birds 

 and their lives are interlocked with this climate and scenery. 



A suitable place from which to begin our tour of the North Atlantic 

 is the St. Paul Rocks. Only three species of sea bird nest on them — 

 the brown booby Sula leucogaster, and the noddy terns, Anoiis stolidus 

 and A. minutus. The islands have been visited by many naturalists, 

 including Charles Darwin, who spent some hours of the afternoon 

 of 15 February 1832 obtaining bird specimens with his geological 

 hammer! 



From here we move to the coast of South America between 

 the Equator and the Caribbean: this is a mud-coast and not, as are 

 many tropical coasts, a coral coast. Indeed, there is no sign of the 

 coastal coral barrier-reef off Brazil until some distance south of the 

 Equator. If we start at the Equator, on the islands in the mouth of 

 the Amazon, we find a typical river bird-community. The water is 

 fresh for some considerable distance outside into the ocean and the 

 birds consist of skimmers {Rynchops nigra) and various river-loving 

 terns such as the gull-billed tern Gelochelidon nilotica, the yellow- 

 billed river-tern Sterna superciliaris, and the large-billed river-tern 

 Phaetusa simplex. Off-shore the true sea-birds come in, and Murphy 

 records species such as Leach's petrel, Wilson's petrel, the Tristan 

 great shearwater, the great skua, boobies and tropic-birds. North of 

 the Amazon mouth the Brazilian Guiana coast is forested down to 

 the muddy shore. Many small rivers, often choked with the debris of 

 tropical forests, flow into it. 



In French Guiana, however, rocky promontories and islets appear, 

 and they are inhabited by some sea-birds; regrettably little is known 

 about the species involved, but they probably include boobies and 

 tropic-birds. Along the coast of Dutch and British Guiana we are once 

 more in a muddy coast with no headlands or islands. North-west 

 of the mouth of British Guiana's main river, the Essiquibo, there are 

 some shell-beaches, but most of the coast is of mangrove-swamp 

 jungle, in which the only animal resembling a sea-bird is the Mexican 

 or bigua cormorant Phalacrocorax olivaceus. Over the Venezuelan 

 border we are at once in the delta of the great river Orinoco. It is a 



