Balearic Shearwater
Encyclopedia
The Balearic Shearwater (Puffinus mauretanicus) is a medium-sized shearwater
in the seabird
family Procellariidae. It was long regarded a subspecies
of the Manx Shearwater
; see there for more on the Puffinus puffinus superspecies
; following an initial split it was held to be a subspecies of the "Mediterranean Shearwater" (Sibley & Monroe 1990) for nearly ten more years, until it was resolved to be a distinct species
, separate from the Yelkouan Shearwater
(Wink et al. 1993, Heidrich et al. 1998, Sangster et al. 2002). It is the last taxon
of the puffinus complex that was recognized as a separate entity.
It appears to belong to a group of Mediterranean and adjacent Atlantic species which includes the Yelkouan Shearwater
(Austin 1996) and one to three prehistorically
extinct taxa, Hole's and possibly also Olson's Shearwater and an undescribed form of unclear distinctness from Menorca (Alcover 2001). Hole's Shearwater may be the closest known relative of P. mauretanicus. The two living Mediterranean lineages had probably separated before the end of the Pliocene
(c.2 mya), as indicated by molecular differences and the Ibiza
n fossil Puffinus nestori from the Late Pliocene or Early Pleistocene
, which may have been the direct ancestor of the present species (Heidrich et al. 1998).
This species breeds on islands and coastal cliffs in the Balearic islands
. Most winter in that sea, but some enter
the Atlantic in late summer, reaching north to Great Britain
and Ireland
.
This species nests in burrows which are visited only at night to avoid predation by large gull
s.
This bird is approximately 35–40 cm long, with an 85–90 cm wingspan. It has the typically "shearing" flight of the genus, dipping from side to side on stiff wings with few wingbeats, the wingtips almost touching the water. This bird looks like a flying cross, with its wing held at right angles to the body, and it changes from dark brown to dirty white as the dark upperparts and paler undersides are alternately exposed as it travels low over the sea.
Apart from the less contrasted plumage
, this species is very similar to the Atlantic
Manx Shearwater and the Yelkouan Shearwater found elsewhere in the Mediterranean. There exists at least one mixed breeding colony of Balearic and Yelkouan Shearwaters, on Minorca
, and the species' winter ranges overlap in the Central Mediterranean; for scientific purposes at least, a combination of morphological
characteristics and DNA sequence
data is suggested to be required for identification of such birds to species (Genovart et al. 2005).
It is under severe threat from the development of holiday resorts near its breeding sites, and also from animals such as cat
s and rat
s. The discovery of Yelkouan Shearwaters in the Minorcan colony suggests that hybridization may also pose a problem (Genovart et al. 2005); the Balearic Shearwater is considered critically endangered
with extinction by the IUCN.
This is a gregarious species, which can been seen in large numbers from boats or headlands, especially on in autumn.
It is silent at sea, but at night the breeding colonies are alive with raucous cackling calls, higher pitched than the Manx Shearwater's.
The Balearic Shearwater feeds on fish
and molluscs. It does not follow boat
s.
Shearwater
Shearwaters are medium-sized long-winged seabirds. There are more than 30 species of shearwaters, a few larger ones in the genus Calonectris and many smaller species in the genus Puffinus...
in the seabird
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...
family Procellariidae. It was long regarded a subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of the Manx Shearwater
Manx Shearwater
The Manx Shearwater is a medium-sized shearwater in the seabird family Procellariidae. The scientific name of this species records a name shift: Manx Shearwaters were called Manks Puffins in the 17th century. Puffin is an Anglo-Norman word for the cured carcasses of nestling shearwaters...
; see there for more on the Puffinus puffinus superspecies
Superspecies
A superspecies is a group of at least two more or less distinctive species with approximately parapatric distributions. Not all species complexes, whether cryptices or ring species are superspecies, and vice versa, but many are...
; following an initial split it was held to be a subspecies of the "Mediterranean Shearwater" (Sibley & Monroe 1990) for nearly ten more years, until it was resolved to be a distinct species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, separate from the Yelkouan Shearwater
Yelkouan Shearwater
The Yelkouan Shearwater, Levantine Shearwater or Mediterranean Shearwater is a medium-sized shearwater in the seabird family Procellariidae.-Description and identification:...
(Wink et al. 1993, Heidrich et al. 1998, Sangster et al. 2002). It is the last taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
of the puffinus complex that was recognized as a separate entity.
It appears to belong to a group of Mediterranean and adjacent Atlantic species which includes the Yelkouan Shearwater
Yelkouan Shearwater
The Yelkouan Shearwater, Levantine Shearwater or Mediterranean Shearwater is a medium-sized shearwater in the seabird family Procellariidae.-Description and identification:...
(Austin 1996) and one to three prehistorically
Prehistory
Prehistory is the span of time before recorded history. Prehistory can refer to the period of human existence before the availability of those written records with which recorded history begins. More broadly, it refers to all the time preceding human existence and the invention of writing...
extinct taxa, Hole's and possibly also Olson's Shearwater and an undescribed form of unclear distinctness from Menorca (Alcover 2001). Hole's Shearwater may be the closest known relative of P. mauretanicus. The two living Mediterranean lineages had probably separated before the end of the 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...
(c.2 mya), as indicated by molecular differences and the Ibiza
Ibiza
Ibiza or Eivissa is a Spanish island in the Mediterranean Sea 79 km off the coast of the city of Valencia in Spain. It is the third largest of the Balearic Islands, an autonomous community of Spain. With Formentera, it is one of the two Pine Islands or Pityuses. Its largest cities are Ibiza...
n fossil Puffinus nestori from the Late Pliocene or Early Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
, which may have been the direct ancestor of the present species (Heidrich et al. 1998).
This species breeds on islands and coastal cliffs in the Balearic islands
Balearic Islands
The Balearic Islands are an archipelago of Spain in the western Mediterranean Sea, near the eastern coast of the Iberian Peninsula.The four largest islands are: Majorca, Minorca, Ibiza and Formentera. The archipelago forms an autonomous community and a province of Spain with Palma as the capital...
. Most winter in that sea, but some enter
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
the Atlantic in late summer, reaching north to Great Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
and Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
.
This species nests in burrows which are visited only at night to avoid predation by large gull
Gull
Gulls are birds in the family Laridae. They are most closely related to the terns and only distantly related to auks, skimmers, and more distantly to the waders...
s.
This bird is approximately 35–40 cm long, with an 85–90 cm wingspan. It has the typically "shearing" flight of the genus, dipping from side to side on stiff wings with few wingbeats, the wingtips almost touching the water. This bird looks like a flying cross, with its wing held at right angles to the body, and it changes from dark brown to dirty white as the dark upperparts and paler undersides are alternately exposed as it travels low over the sea.
Apart from the less contrasted plumage
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...
, this species is very similar to the Atlantic
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
Manx Shearwater and the Yelkouan Shearwater found elsewhere in the Mediterranean. There exists at least one mixed breeding colony of Balearic and Yelkouan Shearwaters, on Minorca
Minorca
Min Orca or Menorca is one of the Balearic Islands located in the Mediterranean Sea belonging to Spain. It takes its name from being smaller than the nearby island of Majorca....
, and the species' winter ranges overlap in the Central Mediterranean; for scientific purposes at least, a combination of morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
characteristics and DNA sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
data is suggested to be required for identification of such birds to species (Genovart et al. 2005).
It is under severe threat from the development of holiday resorts near its breeding sites, and also from animals such as cat
Cat
The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
s and rat
Rat
Rats are various medium-sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus...
s. The discovery of Yelkouan Shearwaters in the Minorcan colony suggests that hybridization may also pose a problem (Genovart et al. 2005); the Balearic Shearwater is considered critically endangered
Critically endangered
Version 2010.3 of the IUCN Red List of Threatened Species identified 3744 Critically Endangered species, subspecies and varieties, stocks and subpopulations.Critically Endangered by kingdom:*1993 Animalia*2 Fungi*1745 Plantae*4 Protista-References:...
with extinction by the IUCN.
This is a gregarious species, which can been seen in large numbers from boats or headlands, especially on in autumn.
It is silent at sea, but at night the breeding colonies are alive with raucous cackling calls, higher pitched than the Manx Shearwater's.
The Balearic Shearwater feeds on fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
and molluscs. It does not follow boat
Boat
A boat is a watercraft of any size designed to float or plane, to provide passage across water. Usually this water will be inland or in protected coastal areas. However, boats such as the whaleboat were designed to be operated from a ship in an offshore environment. In naval terms, a boat is a...
s.