Common murre | |
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Bird calls recorded in Pembrokeshire, Wales | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Charadriiformes |
Family: | Alcidae |
Genus: | Uria |
Species: | U. aalge |
Binomial name | |
Uria aalge (Pontoppidan, 1763) | |
Synonyms | |
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The common murre or common guillemot (Uria aalge) is a large auk. It has a circumpolar distribution, occurring in low-Arctic and boreal waters in the North Atlantic and North Pacific. It spends most of its time at sea, only coming to land to breed on rocky cliff shores or islands.
Common murres are fast in direct flight but are not very agile. They are highly mobile underwater using their wings to 'fly' through the water column, where they typically dive to depths of 30–60 m (100–195 ft). Depths of up to 180 m (590 ft) have been recorded.
Common murres breed in colonies at high densities. Nesting pairs may be in bodily contact with their neighbours. They make no nest; their single egg is incubated between the adult's feet on a bare rock ledge on a cliff face. Eggs hatch after ~30 days incubation. The chick is born downy and can regulate its body temperature after 10 days. Some 20 days after hatching the chick leaves its nesting ledge and heads for the sea, unable to fly, but gliding for some distance with fluttering wings, accompanied by its male parent. Male guillemots spend more time diving, and dive more deeply than females during this time. Chicks are capable of diving as soon as they hit the water. The female stays at the nest site for some 14 days after the chick has left.
Both male and female common murres moult after breeding and become flightless for 1–2 months. Some populations have short migration distances, instead remaining close to the breeding site year-round. Such populations return to the nest site from autumn onwards. Adult birds balance their energetic budgets during the winter by reducing the time that they spend flying and are able to forage nocturnally.
The common murre was formally described and illustrated in 1763 by the Danish bishop Erik Pontoppidan under the binomial name Colymbus aalge. [3] The type locality is Iceland. [4] The species is now placed together with the thick-billed murre in the genus Uria that was described in 1760 by the French zoologist Mathurin Jacques Brisson. [5] The genus name is from Ancient Greek ouria, a waterbird mentioned by Athenaeus. The specific epithet aalge is an old Danish word for an auk. [6]
The auks are a family of seabirds related to the gulls and terns which contains several genera. The common murre is placed in the guillemot (murre) genus Uria (Brisson, 1760), which it shares with the thick-billed murre or Brunnich's guillemot, U. lomvia. These species, together with the razorbill, little auk and the extinct great auk make up the tribe Alcini. This arrangement was originally based on analyses of auk morphology and ecology. [7]
The official common name for this species is Common Murre according to the IOC World Bird List, Version 11.2. [5] while Common Guillemot is used in the UK, [8] Ireland, [9] and often elsewhere in Europe where English is used as a second language. [10]
Five subspecies are now recognised: [5]
The spelling guillemot is of French origin, first attested by Pierre Belon in 1555, but derived from Old (11th century) French willelm, and matched by English variants willock (attested 1631), willick, will and wilkie, all from forms of the name William, cf. French : Guillaume, but ultimately onomatopoeic from the loud, high-pitched "will, willem" begging calls of the newly fledged young of the common guillemot. [12] The American name murre, also known from England (particularly Cornwall) from the 17th century, is by contrast, onomatopoeic of the growling call of adult common guillemots. [12] [13]
The common murre is 38–46 cm (15–18 in) in length with a 61–73 cm (24–29 in) wingspan. [14] Male and female are indistinguishable in the field and weight ranges between 945 g (2 lb 1+1⁄2 oz) in the south of their range to 1,044 g (2 lb 5 oz) in the north. [15] A weight range of 775–1,250 g (1 lb 11+1⁄2 oz – 2 lb 12 oz) has been reported. [16] In breeding plumage, the nominate subspecies U. a. aalge is black on the head, back and wings, and has white underparts. It has a thin dark pointed bill and a small rounded black tail. After the post-breeding moult, the face is white with a dark spur behind the eye, and there are often dark streaks on the flanks. [14] Birds of the subspecies U. a. albionis are dark brown rather than black, most obviously so in colonies in southern Britain. The legs and the bill are dark grey. Occasionally, adults have been seen with yellow-grey legs. In May 2008, an aberrant adult was photographed with a bright yellow bill. [17]
The adults moult into breeding plumage in December–February, even starting as early as November in U. a. albionis, and back into winter plumage soon after leaving the breeding colonies in July to August. The plumage of first winter birds is the same as the adult winter plumage. However, their moult into first summer plumage occurs later in the year than in adults. First year birds often remain in winter plumage as late as May, and their first summer plumage usually retains some white feathers around the throat. [14]
Some individuals in the North Atlantic, known as "bridled guillemots", have a white ring around the eye extending back as a white line. This is not a distinct subspecies, but a polymorphism that becomes more common the farther north the birds breed. [18]
The chicks are downy with blackish feathers on top and white below. By 12 days old, contour feathers are well developed in areas except for the head. At 15 days, facial feathers show the dark eyestripe against the white throat and cheek. [19] They jump from the breeding cliffs at 20–21 days old, long before being fully fledged, and are cared for by the male parent at sea. [14]
The common murre has a variety of calls, including a soft purring noise, but the main call of the adults, often deafening at large colonies, is a growling "murrrr"; the chicks have a food-begging call, a high-pitched whistle "willee", with considerable carrying power.
The common murre flies with fast wing beats and has a flight speed of 80 km/h (50 mph). [20] Groups of birds are often seen flying together in a line just above the sea surface. [14] However, a high wing loading of 2 g/cm2 [21] means that this species is not very agile and take-off is difficult. [22] Common murres become flightless for 45–60 days while moulting their primary feathers. [23] The sound of the wing beats of the murres are often described as similar to a helicopter.
The common murre is a pursuit-diver that forages for food by swimming underwater using its wings for propulsion. Dives usually last less than one minute, but the bird swims underwater for distances of over 30 m (100 ft) on a regular basis. Diving depths up to 180 m (590 ft) have been recorded [24] and birds can remain underwater for a couple of minutes.
The breeding habitat is islands, rocky shores, cliffs and sea stacks. The population is large, perhaps 7.3 million breeding pairs [25] or 18 million individuals. [1] It had been stable, but in 2016 a massive die-off of the birds in the northeast Pacific was reported. The birds seem emaciated and starving; no etiology has been found. [26] In general, potential threats include excessive hunting (legal in Newfoundland), pollution and oil spills. Cape Meares, Oregon is home to one of the most populous colonies of nesting common murres on the North American continent. [27]
Some birds are permanent residents; northern birds migrate south to open waters near New England, southern California, Japan, Korea and the western Mediterranean. UK populations are generally distributed near their breeding colonies year-round, but have been found to make long-distance migrations as far north as the Barents Sea. [28] Common murres rest on the water in the winter and this may have consequences for their metabolism. In the black-legged kittiwake (which shares this winter habit) resting metabolism is 40% higher on water than it is in air. [29]
The common murre can venture far from its breeding grounds to forage; distances of 100 km (60 mi) and more are often observed [30] though if sufficient food is available closer by, birds only travel much shorter distances. The common murre mainly eats small schooling forage fish 200 mm (8 in) long or less, such as polar cod, capelin, sand lances, sprats, sandeels, Atlantic cod and Atlantic herring. Capelin and sand lances are favourite food, but what the main prey is at any one time depends much on what is available in quantity. [30] It also eats some molluscs, marine worms, squid, and crustaceans such as amphipods. It consumes 20–32 g (11⁄16–1+1⁄8 oz) of food in a day on average. It is often seen carrying fish in its bill with the tail hanging out. [18]
The snake pipefish is occasionally eaten, but it has poor nutritional value. The amount of these fish is increasing in the common murre's diet. Since 2003, the snake pipefish has increased in numbers in the North-east Atlantic and North Sea and sandeel numbers have declined. [31]
The common murre nests in densely packed colonies (known as "loomeries"[ citation needed ]), with up to twenty pairs occupying one square metre at peak season.[ citation needed ] Common murres do not make nests and lay their eggs on bare rock ledges, under rocks, or the ground. Despite the high density of murre breeding sites, sites may vary greatly in their quality over small spatial scales. Pairs breeding at those sites of highest quality are more likely to be occupied by a breeding pairs at all population sizes, and more likely to successfully fledge a chick. [32] They first breed at four to nine years old, [33] but most individuals recruit into the breeding population at ages six or seven, [33] although birds may disperse (permanently depart their natal colony) if space is limited. Annual survival probability for birds aged 6–15 is 0.895, [33] and average lifespan is about 20 years. Breeding success increases with age up to age 9–10 to 0.7 fledglings per pair, then declines in the oldest age birds, perhaps indicating reproductive senescence. [33]
High densities mean that birds are close contact with neighbouring breeders. [34] Common murres perform appeasement displays more often at high densities and more often than razorbills. [34] Allopreening is common both between mates and between neighbours. Allopreening helps to reduce parasites, and it may also have important social functions. [35] Frequency of allopreening a neighbour correlates well with current breeding success. [35] Allopreening may function as a stress-reducer; ledges with low levels of allopreening show increased levels of fighting and reduced breeding success. [35]
Courtship displays including bowing, billing and mutual preening. The male points its head vertically and makes croaking and growling noises to attract the females. The species is monogamous, but pairs may split if breeding is unsuccessful. [36] [37]
Common murre eggs are large (around 11% of female weight [38] ), and are pointed at one end. The egg's pyriform shape is popularly ascribed the function of allowing the egg to spin on its axis or in an arc when disturbed, however there is no evidence to support this claim. [39] Various hypotheses have arisen to explain the egg's shape:
Eggs are laid between May and July for the Atlantic populations and March to July for those in the Pacific. The female spends less time ashore during the two weeks before laying. When laying, she assumes a "phoenix-like" posture: her body raised upright on vertical tarsi; wings half outstretched. The egg emerges point first and laying usually takes 5–10 minutes. [42]
The eggs vary in colour and pattern to help the parents recognize them, each egg's pattern being unique. [43] Colours include white, green, blue or brown with spots or speckles in black or lilac. After laying, the female will look at the egg before starting the first incubation shift. [42] Both parents incubate the egg using a single, centrally located brood patch for the 28 to 34 days to hatching in shifts of 1–38 hours. [38]
Eggs can be lost due to predation or carelessness. Crows and gulls are opportunist egg thieves. Eggs are also knocked from ledges during fights. If the first egg is lost, the female may lay a second egg. This egg is usually lighter than the first, with a lighter yolk.[ citation needed ] Chicks from second eggs grow quicker than those from first eggs. However this rapid growth comes at a cost, first chicks have larger fat reserves and can withstand temporary shortages of food.[ citation needed ]
Chicks occupy an intermediate position between the precocial chicks of genus Synthliboramphus and the semi-precocial chicks of the Atlantic puffin. [44] They are born downy and by 10 days old they are able to regulate their own temperature. [19] Except in times of food shortage there is at least one parent present at all times, and both parents are present 10–30% of the time. [45] Both parents alternate between brooding the chick or foraging for food.
Provisioning is usually divided equally between each parent, but unequal provisioning effort can lead to divorce. [37] Common murres are single-prey loaders, this means that they carry one fish at time. The fish is held lengthways in the adult's bill, with the fish's tail hanging from the end of the beak. The returning adult will form its wings into a 'tent' to protect the chick. The adult points its head downwards and the chick swallows the fish head first.
Alloparenting behaviour is frequently observed. Non-breeding and failed breeders show great interest in other chicks, and will attempt to brood or feed them. This activity is more common as the chicks get older and begin to explore their ledge. There has also been a record of a pair managing to raise two chicks. [46] Adults that have lost chicks or eggs will sometimes bring fish to the nest site and try to feed their imaginary chick.
At time of extreme food stress, the social activity of the breeding ledge can break down. On the Isle of May colony in 2007, food availability was low. Adults spent more of their time-budget foraging for their chicks and had to leave them unattended at times. Unattended chicks were attacked by breeding neighbour which often led to their deaths. Non-breeding and failed breeders continued to show alloparental care. [47]
The chicks will leave the nest after 16 to 30 days (average 20–22 days), [15] and glide down into the sea, slowing their fall by fluttering as they are not yet able to fly. Chicks glide from heights as high as 457 m (1,499 ft) to the water below.[ citation needed ] Once the young chick has left the nest, the male is in close attendance for up to two months. The chicks are able to fly roughly two weeks after fledging. Up until then the male feeds and cares for the chick at sea. In its migration south the chick swims about 1,000 km (600 mi). The female remains at the nest site for up to 36 days after the chick has fledged (average 16 days). [48]
Major oil spills double the winter mortality of breeding adults but appear to have little effect on birds less than three years old. [49] This loss of breeding birds can be compensated by increased recruitment of 4–6 year olds to breeding colonies. [49]
Nesting common murres are prone to two main sources of recreational disturbance: rock-climbing and birdwatching. Sea cliffs are a paradise for climbers as well as birds; a small island like Lundy has over 1000 described climbing routes. [50] To minimise disturbance, some cliffs are subject to seasonal climbing bans. [50]
Birdwatching has conflicting effects on common murres. Birdwatchers petitioned the UK government to introduce the Sea Birds Preservation Act 1869. This act was designed to reduce the effects of shooting and egg collecting during the breeding season. [51] Current concerns include managing the effect of visitor numbers at wildlife reserves. Common murres have been shown to be sensitive to visitor numbers. [52]
When common murres are feeding their young, they return with one fish at a time. The provisioning time relates to the distance of the feeding areas from the colony and the numbers of available fish. There is a strong non-linear relationship between fish density and colony attendance during chick-rearing. [53]
In areas such as Newfoundland and Labrador, the birds, along with the related thick-billed murre, are referred to as 'turrs' or 'tuirs', and are consumed. The meat is dark and quite oily, due to the birds' diet of fish. Eggs have also been harvested. Eggers from San Francisco took almost half a million eggs a year from the Farallon Islands in the mid-19th century to feed the growing city. [54]
Auks or alcids are a group of birds of the family Alcidae in the order Charadriiformes. The alcid family includes the murres, guillemots, auklets, puffins, and murrelets. The family contains 25 extant or recently extinct species that are divided into 11 genera. Auks are found throughout the Northern Hemisphere.
Seabirds are birds that are 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. The first seabirds evolved in the Cretaceous period, and modern seabird families emerged in the Paleogene.
Guillemot is the common name for several species of seabird in the Alcidae or auk family, part of the order Charadriiformes. In Europe, the term covers two genera, Uria and Cepphus. In North America the Uria species are called murres and only the Cepphus species are called "guillemots".
The Atlantic puffin, also known as the common puffin, is a species of seabird in the auk family. It is the only puffin native to the Atlantic Ocean; two related species, the tufted puffin and the horned puffin are found in the northeastern Pacific. The Atlantic puffin breeds in Russia, Iceland, Ireland, Britain, Norway, Greenland, Newfoundland and Labrador, Nova Scotia, and the Faroe Islands, and as far south as Maine in the west and France in the east. It is most commonly found in the Westman Islands, Iceland. Although it has a large population and a wide range, the species has declined rapidly, at least in parts of its range, resulting in it being rated as vulnerable by the IUCN. On land, it has the typical upright stance of an auk. At sea, it swims on the surface and feeds on zooplankton, small fish, and crabs, which it catches by diving underwater, using its wings for propulsion.
The common tern is a seabird in the family Laridae. This bird has a circumpolar distribution, its four subspecies breeding in temperate and subarctic regions of Europe, Asia and North America. It is strongly migratory, wintering in coastal tropical and subtropical regions. Breeding adults have light grey upperparts, white to very light grey underparts, a black cap, orange-red legs, and a narrow pointed bill. Depending on the subspecies, the bill may be mostly red with a black tip or all black. There are several similar species, including the partly sympatric Arctic tern, which can be separated on plumage details, leg and bill colour, or vocalisations.
The European shag or common shag is a species of cormorant. It is the only member of the monotypic genus Gulosus. It breeds around the rocky coasts of western and southern Europe, southwest Asia and north Africa, mainly wintering in its breeding range except for the northernmost birds. In Britain this seabird is usually referred to as simply the shag. The scientific genus name derives from the Latin for glutton. The species name aristotelis commemorates the Greek philosopher Aristotle.
The black guillemot or tystie is a medium-sized seabird of the Alcidae family, native throughout northern Atlantic coasts and eastern North American coasts. It is resident in much of its range, but large populations from the high arctic migrate southwards in winter. The bird can be seen in and around its breeding habitat of rocky shores, cliffs and islands in single or smalls groups of pairs. They feed mainly by diving towards the sea floor feeding on fish, crustaceans or other benthic invertebrates. They are listed on the IUCN red list as a species of least concern.
The pigeon guillemot is a species of bird in the auk family, Alcidae. One of three species in the genus Cepphus, it is most closely related to the spectacled guillemot. There are five subspecies of the pigeon guillemot; all subspecies, when in breeding plumage, are dark brown with a black iridescent sheen and a distinctive wing patch broken by a brown-black wedge. Its non-breeding plumage has mottled grey and black upperparts and white underparts. The long bill is black, as are the claws. The legs, feet, and inside of the mouth are red. It closely resembles the black guillemot, which is slightly smaller and lacks the dark wing wedge present in the pigeon guillemot.
The razorbill, razor-billed auk, or lesser auk is a North Atlantic colonial seabird and the only extant member of the genus Alca of the family Alcidae, the auks. It is the closest living relative of the extinct great auk.
The thick-billed murre or Brünnich's guillemot is a bird in the auk family (Alcidae). This bird is named after the Danish zoologist Morten Thrane Brünnich. The very deeply black North Pacific subspecies Uria lomvia arra is also called Pallas' murre after its describer.
The rhinoceros auklet is a seabird and a close relative of the puffins. It is the only extant species of the genus Cerorhinca. Given its close relationship with the puffins, the common name rhinoceros puffin has been proposed for the species.
Christopher Miles Perrins, is Emeritus Fellow of the Edward Grey Institute of Field Ornithology at the University of Oxford, Emeritus Fellow at Wolfson College, Oxford and His Majesty's Warden of the Swans since 1993.
Cepphus is a genus of seabirds in the auk family also referred to as true guillemots or, in North America, simply as guillemots. The genus name Cepphus is from Ancient Greek κέπφος kepphos, a pale waterbird mentioned by Greek authors including Aristotle. The English word "guillemot" is from French guillemot probably derived from Guillaume, "William". "Murre" is of uncertain origins but may imitate the call of the common guillemot.
The swallow-tailed gull is an equatorial seabird in the gull family, Laridae. It is the only species in the genus Creagrus, which derives from the Latin Creagra and the Greek kreourgos which means butcher, also from kreas, meat; according to Jobling it would mean "hook for meat" referring to the hooked bill of this species. It was first described by French naturalist and surgeon Adolphe-Simon Neboux in 1846. Its scientific name is originally derived from the Greek word for gull, "Glaros" and via Latin Larus, "gull" and furca "two-tined fork". It spends most of its life flying and hunting over the open ocean. The main breeding location is in the Galápagos Islands, particularly the rocky shores and cliffs of Hood, Tower and Wolf Islands, with lower numbers on most of the other islands. It is more common on the eastern islands where the water is warmer.
Uria is a genus of seabirds in the auk family known in Europe as guillemots, in most of North America as murres, and in Newfoundland and Labrador as turr. These are medium-sized birds with mainly brown or black plumage in the breeding season. They breed on the coasts of the northern Atlantic and Pacific oceans.
Brachyramphus is a small genus of seabirds from the North Pacific. Brachyramphus is from Ancient Greek brakhus, "short", and rhamphos, "bill". In English the species are named as "murrelets"; this is a diminutive of "murre", a word of uncertain origins, but which may imitate the call of the common guillemot.
A bird colony is a large congregation of individuals of one or more species of bird that nest or roost in proximity at a particular location. Many kinds of birds are known to congregate in groups of varying size; a congregation of nesting birds is called a breeding colony. Colonial nesting birds include seabirds such as auks and albatrosses; wetland species such as herons; and a few passerines such as weaverbirds, certain blackbirds, and some swallows. A group of birds congregating for rest is called a communal roost. Evidence of colonial nesting has been found in non-neornithine birds (Enantiornithes), in sediments from the Late Cretaceous (Maastrichtian) of Romania.
Bird eggs are laid by the females and range in quantity from one to up to seventeen. Clutch size may vary latitudinally within a species. Some birds lay eggs even when the eggs have not been fertilized; it is not uncommon for pet owners to find their lone bird nesting on a clutch of infertile eggs, which are sometimes called wind-eggs.
The term seabird is used for many families of birds in several orders that spend the majority of their lives at sea. Seabirds make up some, if not all, of the families in the following orders: Procellariiformes, Sphenisciformes, Pelecaniformes, and Charadriiformes. Many seabirds remain at sea for several consecutive years at a time, without ever seeing land. Breeding is the central purpose for seabirds to visit land. The breeding period is usually extremely protracted in many seabirds and may last over a year in some of the larger albatrosses; this is in stark contrast with passerine birds. Seabirds nest in single or mixed-species colonies of varying densities, mainly on offshore islands devoid of terrestrial predators. However, seabirds exhibit many unusual breeding behaviors during all stages of the reproductive cycle that are not extensively reported outside of the primary scientific literature.
Timothy Robert Birkhead is a British ornithologist. He has been Professor of Behaviour and Evolution at the University of Sheffield since 1976.
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