Murres

Can you imagine a seabird that can dive almost the length of a football field straight down below the surface of the sea; travels up to 6000 km a year in migration, covering up to 1000 km of that distance by swimming; leaps from cliffs up to 500 m high with half-grown wings at three weeks of age; can live up to 2S years of age; and provides half a million hearty meals for Newfoundlanders every year? This extraordinary bird is a murre, a common seabird found year-round off both the Atlantic and Pacific coasts of Canada.

Murres, and their close relatives the razorbills, dovekies, guillemots, and puffins, are members of a group of black and white, duckshaped seabirds called auks (or Alcidae). These birds spend almost all their lives at sea and dive beneath the surface to feed on fish, squid, shrimp-like crustaceans called krill, and even marine worms; in fact, they eat almost any marine life up to the size of a 30-g fish. Murres resemble small penguins on land and in the water, and they seem to fill the same ecological positions in the northern oceans that penguins occupy in the southern hemisphere.

Species' range

There are two species of murre: the Common Murre Uria aalge (often called the murre or Baccalieu bird in Newfoundland); and the Thick-billed Murre Uria lomvia (known as the Arctic turr or northern turr in Newfoundland). Although they are similar in appearance and are found all around the oceans of the northern hemisphere, the two species usually occur in seawater of different temperatures. The Common Murre is usually found in waters that are free of ice, whereas the Thick-billed Murre occurs almost year-round in colder areas where there is at least some floating pack ice.

Common Murres breed on coastal islands on the Pacific coast of Alaska, British Columbia, Oregon, and California; in the Gulf of St. Lawrence in Quebec; and on the coast of Newfoundland and southern Labrador. Very small numbers of Thick-billed Murres breed among these Common Murres on the Pacific and Atlantic coasts, but most breed in the Arctic regions of Canada, Alaska, and Greenland north of 60ºN. Here they are one of the most numerous seabirds of the northern hemisphere.

Appearance

Murres wear different feather coats, or plumages, at different times of the year. In summer they are black on the back, neck, and upper breast and glossy white below, and look as if they are wearing elegant dinner jackets. The back of the Thick-billed Murre is darker and shinier than the more chocolate-coloured feathers of the Common Murre. In winter, their colours are similar, but the throat, cheeks, and upper breast are also white, with the white extending up the neck to form a streak behind the eye in the Common Murre.

Both species have sharp, dagger-like bills that are flattened from side to side; however, as the name suggests, the bill of the Thick-billed Murre is shorter and stouter. The beak is black, and in summer the two species can be told apart by the distinct white line along the cutting edge of the top half of the Thick-billed Murre's beak. This line is rather faint in winter, when the white streak up behind the eye of the Common Murre is more useful for telling the species apart.

Two distinct forms of the Common Murre occur: the normal form and the bridled, or ringed, form. The bridled form has a white ring around each eye from which a 2-cm-long white line extends, something like a pair of glasses. The presence of the bridle is not related to the age or sex of the murre, but occurs in much the same way as eye colour in humans, and the two forms do interbreed. The proportion of bridled murres is lowest in the southern parts of the breeding range, where bridled birds may make up less than 1% of murres present, compared with a maximum of about 50% in some northern European colonies.

Adaptations for life at sea

Murres are not very good fliers. Because their wings are smaller than those of any other flying bird of their size, murres have to flap very fast to take off, taxiing across the surface of the water and often bouncing off the tops of waves before getting airborne. Although their rapid wingbeats give the illusion that they fly very fast, their speed is only about 60 km/h.

Because their tails are so short, their feet are used as rudders for flying and are spread apart for complicated maneouvres. Murres cannot turn sharply and may have difficulty landing at a colony on stormy days, often bumping into the cliff and circling back to make several attempts before successfully landing on a ledge.

Murres are even more awkward on land because their feet are placed far back on their bodies. They either shuffle along slowly on their haunches or patter erratically with wings flapping wildly. However, murres spend eight or nine months of each year continuously at sea, coming ashore only to breed, and then walking only short distances within their colonies.

Although flying and walking may not be a murre's specialties, swimming and diving certainly are. Unlike most of the ducks that propel themselves under water with their feet, murres dive by flapping their half-open wings, as if flying under water. This explains why their wings are so short, because water has much more resistance than air, and takes much more effort to move through. To support all this flapping, murres have very large breast muscles, which contribute a quarter of their body weight of about I kg, making them meaty birds for the dining table.

Outside the breeding season, murres probably do very little flying. They spend most of their time on or under the surface of the sea and can often be seen diving and chasing each other through the water near the colony. Murres have been recovered drowned in fishing nets set as deep as 180 m, and dives of 100 m appear to be common. It is difficult to think of a bird diving to such depths where the pressure is so great and to imagine how it finds its food in the darkness there. Murres may approach deepswimming schools of fish from below and attack them as they are silhouetted aginst the dim light far above.

Breeding behaviour

Most murres breed where predators such as foxes cannot reach them­­on small ledges on steep cliffs, on offshore stacks, and, in the case of the Common Murre, sometimes on flat rocky islets. Where the two species are found together, Common Murres generally occupy the broader shelves and tops of stacks, whereas Thick-billed Murres are confined to very narrow ledges.

Most murres breed in huge colonies, the largest in Canada being on Funk Island, 55 km off the northeast coast of Newfoundland, where over 400 000 pairs of Common Murres congregate in an area of about 10 ha. Imagine the noise of adults and their chicks calling and squealing, and the smell that results from the droppings of close to a million birds in that small area!

In Newfoundland, Common Murres return to waters near their colonies in March, and first land on them in April: Arctic-breeding Thickbilled Murres reach their colonies in May when the surrounding sea ice breaks up. Early in the season, the birds visit the colony only occasionally, but, as the date of egg laying approaches, at least one member of each pair stays at the breeding site.

No nest is constructedi the single egg is laid directly on the rocky ledge. The relatively large egg, weighing about 100 g, is incubated continuously by one of the parents, which take equal turns of one or two days sitting while the other is feeding at sea. To keep the egg warm, the bird tucks it under its feathers against the bare skin of the "brood patch" on the lower belly.

An egg may be dislodged from a narrow ledge, especially if birds are disturbed and fly off in panic. When an egg is lost, a second may be laid after about two weeks. Occasionally, if two eggs are lost in quick succession, a third may be laid, but this is the most the female is able to produce in one season. A chick hatched from a late egg may not have time to grow to fledging before the short summer ends.

The chick hatches after about a month and is covered with an insulating coat of downy feathers. The parents continue to brood the chick as long as it stays at the colony. One parent always stays with the chick while the other brings it food, usually fish weighing from 5 to 20 g, which it may gather as far as 100 km from the colony. In three weeks, the chick grows from about 70 g at hatching to about 250 g or a quarter of the adult weight, while it grows a set of waterproof feathers to replace the down coat.

At three weeks of age, the chick leaves the colony with the male parent in the late evening, so that by dawn it can be as far as possible from the predatory gulls found on the colony. At this age, it does not have proper flight feathers, just short, stubby wings that are not large enough to enable it to actually take off. In colonies on high cliffs, the chick hurls itself from its ledge and glides steeply down to the sea, closely followed by its parent. At breeding colonies on low islands, the chick and adult scramble on foot down to the water.

A Thick-billed Murre chick reared in one of the high-Arctic colonies has to make a long migration from its breeding grounds to the wintering area off Newfoundland. The first part of this journey, perhaps as much as 1000 km, is made entirely by swimming, because the young bird becomes able to fly only one or two months after leaving the colony. The chick continues to grow at sea and apparently starts to feed itself as soon as it takes to the water, although the accompanying parent also passes it additional food. The remarkable swimming migration of these Arctic murre chicks is unique among birds; no other species travels so far at such a young age, while still unable to fly.

Fall and winter

Between August and October, adult murres lose all their wing feathers simultaneously and are completely flightless for several weeks while they grow a new set of feathers. However, during this period they swim long distances to autumn feeding grounds­­for the high-Arctic Thick-billed Murres these are off west Greenland, while those breeding farther south move to the Labrador coast.

The population concentrates in the waters off southern Labrador and northern Newfoundland as the arctic pack ice moves south, and about four million Thick-billed Murres have probably reached this area by early winter. The majority of Common Murres have apparently moved farther south, to the Grand Banks off Newfoundland, Georges Bank off Nova Scotia, and beyond. Thick-billed and Common Murres that breed in Alaska also move southwards, many spending the winter in the coastal waters of British Columbia.

Murres that breed off the Atlantic coast are seldom seen with their chicks in the fall when they are well offshore. On the other hand, Common Murres that breed off Oregon and California actually move north into the sheltered waters of the B.C. coast. Here the adults and chicks can be seen in pairs, calling and feeding together, from vantage points along the coast or from coastal ferries. These birds feed on abundant fall herring stocks and leave the area by late winter to move offshore.

From November to March, Thick-billed Murres are common in the bays around the coast of Newfoundland, except where sea ice covers the surface, and as far out to sea as the edge of the continental shelf. We do not know how many murres concentrate inshore, but even where the birds are close to the coast, they generally feed in water more than 50 m deep. In winter, they occur in loose flocks ranging in size from a few birds up to several hundred, which are called "companies" by Newfoundland hunters.

When murres first arrive in Newfoundland waters in late fall, most continue to feed on young squid or small fish such as Arctic cod, Atlantic cod, sand lance, and capelin. However, as the surface waters get colder, these fish descend into slightly warmer but much deeper layers, making it harder for murres to feed on them. The birds then switch to feeding on small, pinkish, shrimplike crustaceans or euphausiids that swarm in high numbers near the surface in mid- to late winter.

Some murres may be driven inland during severe winter storms, and periodic "wrecks" of murres, usually Thick-billed Murres, have been recorded in the Great Lakes area and the eastern United States. These birds are usually weakened by initial starvation, and few survive to return to the ocean. In just one week of rough weather that prevents it from feeding well, a murre can "burn up" most of the thick layer of body fat it accumulates during better feeding conditions.

Causes of death

Murres can live a very long time. We know from tagging them with metal leg-bands that wild birds of both species have survived for 25 years. A few may live even longer, because the aluminum bands used 30 years ago may have worn through and fallen off the leg before the oldest birds carrying them had died. Stronger, stainless steel bands are now being used to give a better idea of their maximum life span.

Despite their potential life span, many murres fall victim to legal hunting quite young, often before beginning to breed at 5 years of age. Some are hunted as they migrate off the coast of Greenland, and Canadian native people shoot a few thousand near the colonies in a traditional food hunt each year.

Most murres die off Newfoundland and Labrador, where about 750 000 are shot each winter in the traditional "turr hunt". About half of these murres are young birds that have already reached full size, although they are still only four to eight months old. They can be distinguished from older murres in the hand because they have smaller beaks and lack the bony ridges that, on older birds, can be felt beneath the skin between the eyes.

Because these seabirds spend so much time on the surface of the ocean, they are very vulnerable to contamination by oil floating on the sea. Most murres that swim through a slick of oil are left with it smeared on their feathers. Birds contaminated in this way usually die. Some are killed by swallowing the toxic oil in the course of preening feathers to clean them. Most die because the oil mats the feathers together, destroying their natural insulation and waterproofing, and lets cold seawater penetrate to the skin. Surveys by the Canadian Wildlife Service in southeastern Newfoundland have found that up to 75~o of all murres found dead on beaches in winter have oil, mainly heavy bunker fuel oil, matting their feathers.

Near Newfoundland colonies, many Common Murres that dive to feed on capelin are drowned in gill-nets set for cod, which feed on the same schools of capelin. Large numbers of Thickbilled Murres migrating down the west coast of Greenland are similarly killed in salmon gillnets. Out of a total population of about six million Thick-billed Murres in the western Atlantic, close to a million die every year as a result of human activities: by hunting, oil pollution, and drowning in flshing nets. This is too many for a bird that only begins to breed when it is five years old, and then lays only one egg a year.

Murre conservation

Murres cannot be legally sold; however, in small fishing communities in Newfoundland and Labrador, hunters share their "turrs" with relatives and friends, and in most winters these birds still provide welcome variety to the diet in outport communities.

The murres were once hunted with muzzleloading single-shot guns from slow-moving fishing boats. Now most hunters use semiautomatic shotguns and small 5- to 6-m wooden or fiberglass speed-boats with powerful outboard motors that can travel almost as fast as the murres can fly. These changes have made the murres more vulnerable to the hunters. Because the meat they provide is no longer essential to ensure that fishermen and their families survive the winter, some of it is now sold illegally.

Common Murres make up less than 10% of the birds that are shot, and their numbers have increased dramatically in Newfoundland and Labrador over the past 30 years. However, on the north shore of the Gulf of St. Lawrence, numbers of Common Murres and other seabirds are still low due to illegal hunting and egg gathering.

Surveys at colonies in the Canadian Arctic have shown that numbers of breeding Thickbilled Murres have probably declined during the past 30 years, and some colonies in Greenland have been completely wiped out. Although the number of birds shot in Newfoundland and Labrador was not restricted in the past, when murres provided necessary winter food in isolated communities, controls are now needed to ensure that the murre populations can recover and the traditional turr hunt be maintained at an acceptable level.

With tens of thousands of birds crowded into a colony on a small island or headland, many could be killed if a major oil spill, or similar pollution incident, occurred nearby. Breeding areas are also very susceptible to disturbance by people visiting the colony, by boats passing close to shore, and by aircraft flying low overhead. Most damage is caused when the birds have eggs, because the adult murres panic and fly off, knocking some eggs from the breeding site and exposing others to predators. Gulls, for example, which are normally kept away by the stabbing bills of the adult murres, are quick to swoop in to pick up eggs or chicks that are left unprotected once the adult murres have left.

There are several places in Canada where one can watch murres without disturbing them. Large colonies can be seen from the dramatic cliffs at Cape St. Mary's on the Avalon Peninsula of southern Newfoundland, and from tour boats at Witless Bay just south of St. John's, Newfoundland, and at Bonaventure Island on the Gaspé Peninsula in Quebec. Murres can also be seen at sea, from ferries and coastal boats around Newfoundland and Labrador, and in the sheltered waters between Vancouver Island and the mainland of British Columbia and Washington.

Many of the most important murre colonies are now included in federal or provincial wildlife sanctuaries, but others still await such protection. If all of us­­hunters, and birdwatchers, fishermen, and tourists­­act responsibly and recognize the effects that our actions may have, we can help these fascinating birds to remain a familar part of our Canadian seascape.

Reading list

• Brown, R.G.B. 1986. Revised atlas of eastern Canadian seabirds, 1. Shipboard surveys. Canadian Wildlife Service, Ottawa. 110 pp.
• Brown, R.G.B., D.N. Nettleship, P. Germain, C.E. Tull, and T. Davis. 1975. Atlas of eastern Canadian seabirds. Canadian Wildlife Service, Ottawa. 220 pp.
• Freuchen, P. and F. Salomonsen. 1958. The arctic year. G.P. Putnam & Sons, New York. 438 pp.
• Gaston, A.J. and l.L. Jones. 1984. Guide to the seabirds of eastern Canada. Canadian Wildlife Service, Ottawa. 53 pp.
• Gaston, A.J. and D.N. Nettleship. 1981. The Thick-Billed Murres of Prince Leopold Island. Canadian Wildlife Service Monograph No. 6, Ottawa. 350 pp.
• Godfrey, W.E. 1986. The birds of Canada. Rev. ed. National Museums of Canada, Ottawa. 595 pp.
• Nettleship, D.N. and T.R. Birkhead. 1985. The Atlantic Alcidae. Academic Press, Orlando. 574 pp.
• Tuck, L.M. 1961. The murres. Canadian Wildlife Service Monograph No. 1, Ottawa. 260 pp.

	Canadian Wildlife Service - Hinterland Who's Who series Reproduced with permission of the Minister of Public Works and Government Services Canada, 1999. Copyright © 1999 Environment Canada. All rights reserved. Last update: 19 January 1999