Ocean and Sea Birds

Main Oceanic Regions.

• Petrels (including Storm and Diving) are found in all the oceans. The Northern Fulmar has a southern hemisphere counterpart.

• Albatross are found in the Pacific, Indian and Southern oceans.

• Frigatebirds are found in the Pacific, Atlantic Indian and Tropical oceans. They are piratical scavengers.

• Tropicbirds are only found in the Tropical Oceans.

• Gannets favour coastal areas and are found in the Atlantic ocean, North Sea, African and Australian coastal regions.

• Boobies favour island coasts and are found in the Pacific, Indian and Tropical oceans.

• Auks, Murres (Guillemots), Razorbills and Puffin are found in coastal areas of the Northern hemisphere whereas Penguins are found in coastal areas of the Southern hemisphere.

• Terns found in marine and inland waters, Skimmers catch fish near the water surface by skimming the surface with their dagger shaped beaks open.

• Small Gulls tend to be surface feeders but the Large Gulls have become scavengers taking whatever food is available, both at sea and on land. Jaegers and Skuas are pelagic, piratical scavengers as are the Frigate Birds of the southern oceans.

Plunge Divers and Swim Pursuers.

The way in which these birds have evolved to feed in a very similar manner, albeit in different oceans of the world, has resulted in them looking alike and behaving in a similar fashion. Ornithologists call this Convergent Evolution.

What these birds have in common is the ability to dive and swim pursuing fish by sight. They are a disparate group of unrelated predators which have evolved with different shaped beaks enabling them to specialse in catching different kinds of prey. On the one hand we have the dagger beaks of the Tropicbirds and Terns, used to spear or grip their prey, compared to the somewhat Parrot-like beak of the Puffin which can hold a mouthfull of sand eels caught by pursuit in the sea. These are the two extremes.

  • Penguins had become flightless, with a body form close to that we know today, by about 70 mya. They are now only found in the Southern Hemisphere where they favour cold waters.
  • Loons can be considered to be the Northern Hemisphere counterparts of the Penguin. They tend to prefer fresh water lakes. Both have their feet placed well to the rear of the body so that, on land, they stand vertically but look very ungainly. The Loons probably evolved about 50 mya.
  • Tropicbirds which are only found in the tropical oceans probably evolved at about the same time as the Loons. They plunge dive taking prey with their dagger beaks usually close to the water surface.
  • Petrels, Shearwaters, Storm Petrels and Diving Petrels are widespread. The Northern Fulmar (which is a Petrel) has a southern hemisphere counterpart.
  • Auks, in which I include Murre, Guillemot, Razorbill and Puffin, tend to favour the cooler waters of the Northern Hemisphere. It appears possible that Auks and Gulls shared the same ancestor and that the two diverged about 30 mya.
  • Gannets and Boobies are sea birds which have taken plunge diving to a new level. They appear to have evolved about 20 mya.

Returning to the Petrels the Magellanic Diving Petrel (Pelecanoides magellani in family Pelecanoididae) and order Procellariiformes and the Little Auk (Alle alle in family Alcidae) and order Charadriiformes appear almost identical in appearance. The former is found in the Southern Ocean and the latter in the North Atlantic Ocean. Evidence suggests that the Diving Petrel might have evolved before the Little Auk.

  • Brown Pelican is a punge diver but the other Pelicans find it easier to scoop their prey into the pouch below their lower mandible.
  • Terns seem to have evolved after the Auks and Gulls perhaps 20 mya. Some Terns hover before taking their prey just below the water surface.
  • Skimmers have surely evolved from the Terns. They skim the water surface scooping fish from the surface with their lower mandible.