Also known as procellariidae, shearwaters and petrels are an enigmatic group of pelagic birds which are typically characterized by their tube-shaped nostrils. They dwell much on waters (easily adapted to oceanic environments) to the extent that they only come to land for breeding. Some of these birds are residents and like breeding only on islands, however others are long distance migrants.
Some of the species like those represented by procellarid group (the tube-nosed species) can be seen in expansive oceans across the globe but predominantly the southern oceans have become favorite homes of these beautiful creatures.
The Diving Petrels & Prions, Shearwaters, Fulmars and numerous species of petrel ranging from Westland Petrel to the Snow Petrel are some of the members of this group.
A good number of locations support multitude of sea birds, including half a million Sooty Shearwaters surrounding California in the northern summer, Monterey Bay shores, over three million Short-tailed Shearwaters that migrate to Tasmania from Japanese waters yearly. For sea-watchers in northern waters, autumn storms often foreshadow passages of wave-clipping shearwaters.
Whoever has been part of any oceanic voyage in southern ocean can testify about the varieties and densities of these beautiful seabirds. Unfortunately most of these species are less common, endangered and little is known about them. This implies that a lot has to be done to ensure their continued existence.
Most procellarids breed on offshore islands commonly within caves and burrows. The fact that these birds nest on the ground, they are subject to being attacked by land predators like snakes, cats, and dogs. An example of them is in Australian shores that often lose their young ones to snakes. Their continuous exposure to predators has resulted into decline in their numbers across the globe. Therefore, there is an urgent need to double efforts in as far as their conservation is concerned.
Apparently, a step towards conservation of these birds has been taken by some countries and conservation agencies whereby they have declared one historic breeding island that is free from predators. This has been done for the first time in the world for the past centuries and it is something that ought to be implemented in as many locations as possible. These beautiful creatures have to be preserved for future generations.
Movements.
A number of shearwaters migrate over long distances perhaps and interestingly some sooty shearwaters can cover long journeys in excess of fourteen thousand kilometer (about 8,700 miles) from Falkland Islands – their breeding places and travel as far as North Atlantic Ocean – off northern Norway. A study revealed that Sooty shearwaters migrate almost sixty four thousand kilometers (about 40,000 miles) in one year; which made them set a record of being the longest animal migrators ever recorded electronically.
Breeding.
Like stated earlier, shearwaters visit land only for breeding purposes, which is usually done in moonless nights in order to survive predators. In other words, they are nocturnal in their colonial breeding sites. They often make their breeding nests in burrows and are commonly identified by the eerie contact calls they give on their night time visits. It is in their nests that they lay white eggs. These eggs later hatch into notably short-tailed chicks (for some specific species) and sooty shearwaters are subject to “mutton-birding” where they harvest from their nest burrows for food.
Feeding.
Shearwaters mainly feed on fish, squid and some similar oceanic food. Some of these birds are usually spotted following fishing boats to take scraps, particularly the sooty shearwaters. They also follow whales to feed on fish disturbed by them. The most common feeding technique employed by these birds is diving (some dive to depths of about 210ft. / 70m)
Shearwaters and petrels in Uganda.
Out of seventy five (75) species of these birds in the whole world, only one (1) species is known to exist in Uganda.
