Diving petrel
Encyclopedia
The diving petrels are seabird
s in the bird
order Procellariiformes. There are four very similar species all in the family Pelecanoididae and genus Pelecanoides (Lacépède, 1799), distinguished only by small differences in the coloration of their plumage
and their bill
construction.
Diving petrels are auk-like small petrel
s of the southern oceans. The resemblances with the auk
s are due to convergent evolution
, since both families
feed by pursuit diving, although some researchers have in the past suggested that the similarities are due to relatedness. Amongst the Procellariiformes the diving petrels are the family most adapted to life in the sea rather than flying over it, and are generally found closer inshore than other families in the order.
Diving petrels are plankton
feeders, taking mostly crustacean
prey such as krill
, copepod
s and the amphipod Themisto gaudichaudii
, also taking small fish and squid
. They have several adaptations for obtaining their prey including short powerful wings, a gular pouch for storing food, and their nostrils open upwards rather than forward pointing as it is in other tubenose
s.
(4-7 oz
). They are highly uniform in appearance, and very difficult to separate when seen at sea. They are best separated by the size and shape of their short bills
. The plumage
is shining black on the top and white on the underside. Their wings are short, particularly with regards to overall body size, and used in a highly characteristic whirring flight. This flight is low over the water and diving petrels will fly through the crests of waves without any interruption of their flight path. In the water these wings are half folded and used as paddles to propel the bird after its prey.
s nest in colonies on islands. One white egg
is laid in a burrow in turf or soft soil that is usually covered with vegetation, feather
s, or small rocks. They are nocturnal at the breeding colonies. It has a long period of parental care (around 45 to 60 days) in the burrow, but once the chick fledge
s out to sea it is on its own.
and the Magellanic Diving Petrel, have highly restricted ranges around South America
's coasts, whilst the Common Diving Petrel
and the South Georgia Diving Petrel range widely across the southern oceans, breeding on islands off New Zealand, sub-Antarctic
islands in the Indian Ocean
, and islands in the south Atlantic (like Tristan da Cunha
).
Diving petrels are among the world's most numerous birds, with Common and South Georgia Diving Petrels numbering several million pairs each. The Peruvian Diving Petrel, on the other hand, is threatened by guano
extraction, introduced species
and climate change
, and is listed as an endangered species
.
, and some taxonomic works treat them as such.
The four species are:
The evolution
and systematics of these birds is not well researched. Several populations were described as distinct species and while most of them are only subspecies, some may indeed be distinct. The prehistoric fossil record was long limited to very fragmentary remains described as P. cymatotrypetes found in Early Pliocene
deposits of Langebaanweg
, South Africa
; while this bird apparently was close to the Common Diving Petrel, no members of the genus are known from South African waters today.
In 2007, a humerus
piece from New Zealand
was described as P. miokuaka. This was found in Early/Middle Miocene
deposits and just as may be expected, it far more resembles diving petrels than any other known bird, but presents a less apomorphic condition.
Seabird
Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
s in the bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
order Procellariiformes. There are four very similar species all in the family Pelecanoididae and genus Pelecanoides (Lacépède, 1799), distinguished only by small differences in the coloration of their plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
and their bill
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
construction.
Diving petrels are auk-like small petrel
Petrel
Petrels are tube-nosed seabirds in the bird order Procellariiformes. The common name does not indicate relationship beyond that point, as "petrels" occur in three of the four families within that group...
s of the southern oceans. The resemblances with the auk
Auk
An auk is a bird of the family Alcidae in the order Charadriiformes. Auks are superficially similar to penguins due to their black-and-white colours, their upright posture and some of their habits...
s are due to convergent evolution
Convergent evolution
Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...
, since both families
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
feed by pursuit diving, although some researchers have in the past suggested that the similarities are due to relatedness. Amongst the Procellariiformes the diving petrels are the family most adapted to life in the sea rather than flying over it, and are generally found closer inshore than other families in the order.
Diving petrels are plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
feeders, taking mostly crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
prey such as krill
Krill
Krill is the common name given to the order Euphausiacea of shrimp-like marine crustaceans. Also known as euphausiids, these small invertebrates are found in all oceans of the world...
, copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
s and the amphipod Themisto gaudichaudii
Themisto gaudichaudii
Themisto gaudichaudii is an amphipod crustacean of the suborder Hyperiidea.-Relatives:The 260 species of hyperiid amphipods are large-eyed and planktonic amphipods, whereas gammarid amphipods have smaller eyes and tend to live on the sea floor. The handful of species of the genus Themisto are the...
, also taking small fish and squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
. They have several adaptations for obtaining their prey including short powerful wings, a gular pouch for storing food, and their nostrils open upwards rather than forward pointing as it is in other tubenose
Procellariiformes
Procellariiformes is an order of seabirds that comprises four families: the albatrosses, petrels and shearwaters, storm petrels, and diving petrels...
s.
Description and morphology
The diving petrels are small petrels that measure between 19–23 cm (7.5–9 in) and weigh between 120-200 gGram
The gram is a metric system unit of mass....
(4-7 oz
Ounce
The ounce is a unit of mass with several definitions, the most commonly used of which are equal to approximately 28 grams. The ounce is used in a number of different systems, including various systems of mass that form part of the imperial and United States customary systems...
). They are highly uniform in appearance, and very difficult to separate when seen at sea. They are best separated by the size and shape of their short bills
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
. The plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
is shining black on the top and white on the underside. Their wings are short, particularly with regards to overall body size, and used in a highly characteristic whirring flight. This flight is low over the water and diving petrels will fly through the crests of waves without any interruption of their flight path. In the water these wings are half folded and used as paddles to propel the bird after its prey.
Breeding
These birdBird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s nest in colonies on islands. One white egg
Bird egg
Bird eggs are laid by females and incubated for a time that varies according to the species; a single young hatches from each egg. Average clutch sizes range from one to about 17...
is laid in a burrow in turf or soft soil that is usually covered with vegetation, feather
Feather
Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds and some non-avian theropod dinosaurs. They are considered the most complex integumentary structures found in vertebrates, and indeed a premier example of a complex evolutionary novelty. They...
s, or small rocks. They are nocturnal at the breeding colonies. It has a long period of parental care (around 45 to 60 days) in the burrow, but once the chick fledge
Fledge
Fledge is the stage in a young bird's life when the feathers and wing muscles are sufficiently developed for flight. It also describes the act of a chick's parents raising it to a fully grown state...
s out to sea it is on its own.
Status and conservation
Of the four species two, the Peruvian Diving PetrelPeruvian Diving Petrel
The Peruvian Diving Petrel, Pelecanoides garnotii , is a small seabird that feeds in offshore waters in the Humboldt Current off Peru and Chile. Like the rest of the diving petrels it is a nondescript bird, with a dark back and pale belly, and blue feet, and can be separated from the rest of its...
and the Magellanic Diving Petrel, have highly restricted ranges around South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
's coasts, whilst the Common Diving Petrel
Common Diving Petrel
The Common Diving Petrel , also known as the Smaller Diving-Petrel or simply the Diving-Petrel, is a diving-petrel, one of four very similar auk-like small petrels of the southern oceans...
and the South Georgia Diving Petrel range widely across the southern oceans, breeding on islands off New Zealand, sub-Antarctic
Antarctic
The Antarctic is the region around the Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica and the ice shelves, waters and island territories in the Southern Ocean situated south of the Antarctic Convergence...
islands in the Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
, and islands in the south Atlantic (like Tristan da Cunha
Tristan da Cunha
Tristan da Cunha is a remote volcanic group of islands in the south Atlantic Ocean and the main island of that group. It is the most remote inhabited archipelago in the world, lying from the nearest land, South Africa, and from South America...
).
Diving petrels are among the world's most numerous birds, with Common and South Georgia Diving Petrels numbering several million pairs each. The Peruvian Diving Petrel, on the other hand, is threatened by guano
Guano
Guano is the excrement of seabirds, cave dwelling bats, and seals. Guano manure is an effective fertilizer due to its high levels of phosphorus and nitrogen and also its lack of odor. It was an important source of nitrates for gunpowder...
extraction, introduced species
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
and climate change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
, and is listed as an endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
.
Systematics and evolution
Some studies published on the phylogeny of the petrels suggests that the diving petrels are actually members of the family ProcellariidaeProcellariidae
The family Procellariidae is a group of seabirds that comprises the fulmarine petrels, the gadfly petrels, the prions, and the shearwaters. This family is part of the bird order Procellariiformes , which also includes the albatrosses, the storm-petrels, and the diving petrels.The procellariids are...
, and some taxonomic works treat them as such.
The four species are:
- Peruvian Diving PetrelPeruvian Diving PetrelThe Peruvian Diving Petrel, Pelecanoides garnotii , is a small seabird that feeds in offshore waters in the Humboldt Current off Peru and Chile. Like the rest of the diving petrels it is a nondescript bird, with a dark back and pale belly, and blue feet, and can be separated from the rest of its...
Pelecanoides garnotii - Magellanic Diving Petrel Pelecanoides magellani
- South Georgia Diving Petrel Pelecanoides georgicus
- Common Diving PetrelCommon Diving PetrelThe Common Diving Petrel , also known as the Smaller Diving-Petrel or simply the Diving-Petrel, is a diving-petrel, one of four very similar auk-like small petrels of the southern oceans...
Pelecanoides urinatrix
The evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
and systematics of these birds is not well researched. Several populations were described as distinct species and while most of them are only subspecies, some may indeed be distinct. The prehistoric fossil record was long limited to very fragmentary remains described as P. cymatotrypetes found in Early Pliocene
Pliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
deposits of Langebaanweg
Langebaanweg
Langebaanweg is a town on the southwest coast of South Africa, in Western Cape Province.It is the location of the air force base AFB Langebaanweg l....
, South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
; while this bird apparently was close to the Common Diving Petrel, no members of the genus are known from South African waters today.
In 2007, a humerus
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
piece from New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
was described as P. miokuaka. This was found in Early/Middle Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
deposits and just as may be expected, it far more resembles diving petrels than any other known bird, but presents a less apomorphic condition.