Scientific name: Uria aalge
Danish: Atlantisk Lomvie
English: Common Guillemot
German: Trottellummen
Greenland: Agasiggugtoq
Japanese: Umigarasu (Sea Crow)
North American: Thin-billed Murre; Murre
Russian: Kara; Arra
St. Lawrence Island:Aqavoghanuk Welsh: Eligugs; Willocks

In Wales, fishermen refer to the cliff dwellings of murres as eligug walls, and because the sound made by the begging chicks resembles "Willou-willou", the young is called a willock. More generally the murre is called the guillemot in England, the name reserved for the "sea pigeons" in the New World. The North American name, murre, is also of British origin. It is attributed to Cornwall and is descriptive of the murmuring sound made by the adult bird. One can almost imitate the noise by extending the name and by rolling the "rr" as in "murrrrre." See the sonograph of a single murre growl in the Appendix.)

The Common Murre is present in very large numbers in both the Atlantic and Pacific oceans and in both temperate and Arctic seas. it is undoubtedly one of the most populous seabirds of the northern hemisphere, but there is evidence that the overall numbers have declined in recent years. Thirty-five years ago it was estimated that there were tens of millions of murres. Recent counts using more accurate methods indicate considerably lower figures, although in Scotland, Newfoundland and Labrador there are indications of gradually increasing populations once again.^{439, 255} Since murres breed at greater densities than other species they are difficult to count, and since colony attendance may vary with tide, weather, feeding conditions and stage of breeding, figures should be considered as estimates at best.⁵⁵⁸ Censuses made in the British Isles 1969-80 calculate that almost 800,000 pairs of Thin-billed Murres nest there.^{142, 439} Iceland has the highest population for the North Atlantic with the possibility of 1.6 million nesting pairs. In 24 colonies in Atlantic Canada, there are about 600,000 pairs more than half of which nest on Funk Island, Newfoundland.^{334, 432} Total for the entire Atlantic may exceed 8 million birds.⁴³⁹ A late seasonal thaw may have caused a major decrease from 60,000 birds in 1972 to about 15,000 in 1976 at colonies at Kongkok Bay, St. Lawrence Island, Alaska. Numbers also declined at Bluff, Alaska between 1979 and 1983.408 The estimated total for all of Alaska is about five million birds.⁵⁷⁰ In 1988 about 426,000 birds were counted at nesting colonies along the Oregon Coast.⁵²

During the last century, murre eggs were collected from the North American colonies to be sold as a substitute for hens' eggs. Collecting on the Farallon Islands near San Francisco almost decimated the murre colonies there and precipitated a shooting feud between two competing egg companies. Today on the Farallones, large areas formerly occupied by murres are now packed with Brandt's Cormorants. A few murres persist in small groups between the cormorants and in a few scattered larger colonies. Where once were hundreds of thousands of murres, the number now stands at only 20,500 birds.⁴ However, huge colonies may not be advantageous to seabirds since there is, at least in some situations, lower breeding success at large colonies compared with smaller ones. This may be due to less food availability near large concentrations of birds.²⁸⁷ Studies conducted by Tim Birkhead on Skomer Island, Wales indicate contrary evidence showing, due to higher security, that dense groups have higher breeding success than sparsely arranged groups.⁷¹ Successful breeders from dense areas tend to return to their breeding sites early in the Fall to defend the site and are more successful than those which return in the Spring to the edges of the colony. It is obvious that hundreds of thousands of murres in one location may have difficulty in providing sufficient food for rearing young, but when the population is not so large, murres maybe better off when they nest densely packed together than to sparsely arrange themselves.^{255, 256} Over a three-year study at Gannet Islands, Labrador, breeding success averaged 82 per cent for the Common Murre.⁸⁷

The murre is the largest of our living alcids, weighing on the average a little more than 1,000 grams and standing more than 50 centimeters tall. When guarding eggs and young, murres are not especially timid: at breeding sites on the Farallon Islands it is possible to creep to within a meter or two from incubating birds without soliciting more than a few extra bows and growls. However, before eggs are laid, murres are wary birds and leave their ledges in mass at the slightest disturbance. (See Figure 5 of the Appendix for spring and summer average weight changes in murres.)

This sleek, black-and-white, and rather elegant bird may be observed at many locations around our coasts where it congregates and breeds on rocks not far from shore. One such place is at Yaquina Head, Oregon. Another is at Cape Meares, near Tillamook, Oregon. Here, the whole process of breeding may be viewed with binoculars from the safety of of the mainland without the slightest disturbance to the colony. The mass of birds appear to the observer as bedlam and confusion - a growling din. But each bird knows exactly where its egg or chick is among the seething, clamoring hoard.

Winter plumage reflects more white around the head, neck, and wings than the nuptial dress of spring and summer. Variation between summer and winter plumage patterns occurs also in chicks within the same colony.⁸⁶ A narrow black line curving back from the eye shows that the bird is in winter dress. In British waters, fishermen call the wintering murre "herring bird" since they are always associated with shoals of herring which eat the smaller fish also preferred by the birds. (Figure 16 of the Appendix depicts annual molt sequence in murres.)

A varying percentage of birds of Atlantic populations sport a white eye margin coupled with a posteriorly directed, stylish stripe. These birds, which tend to associate together within a colony, are referred to as bridled, spectacled, or ringed.^{74, 296} No bridled specimens are found among Pacific Ocean populations. In European waters, the number sporting these white eye margins increases from France to Norway. Only 0.1 percent of the birds in France are spectacled, and in southern England and on the Baltic coasts, 1 to 2 percent. (In Scottish populations, 10 to 30 percent have this feature; the Faeroe Islands show 31 to 34 percent; Norway, 50 percent; Bear Islands, 53 percent; and on Soviet islands, 40 to 42 percent. Eighteen percent of the population along the coasts of Atlantic North America are bridled.⁵⁶⁴ There are recent figures to indicate that the numbers of the bridled form may be declining. 77 Possibly the name "guillemot" has been derived from the French word for quotation marks, "guillemet" and is inspired by these elegant eye markings.

Murres and other seabirds feed in large numbers, especially where upwellings and salinity variations attract abundant food resources. Regions where currents meet, where estuaries pour out their less saline water, where icebergs melt, and where temperature gradients occur in the sea are areas where abundant planktonic food items attract organisms of the entire oceanic food chain. Small fish are attracted here as are the larger fish which prey upon them. The birds are there for their share as is man with his net, though perhaps for more than his share: hundreds of thousands of murres and other seabirds perish annually in fishing nets. In pursuit of its prey, the murre is a most proficient diver. Ninety-five percent of its diet, as determined by extensive studies by Belopol'skii in Soviet areas, consists of small fish such as young polar cod and capelin. ⁶¹ In the western Atlantic, murres feed chiefly on capelin, sand eels, and to some extent on the young of commercial fish such as Atlantic cod, Greenland cod, and halibut.⁶¹³ At a Labrador location chicks were fed 78 to 80 percent capelin.⁸⁷ In Scotland during the breeding season,more than 80 percent of the fish brought to the young are sandeels.²⁵⁴ During the winter months in Alaskan waters 84 percent of their food is crustaceans.⁵²⁰

In the more temperate areas of its range, the murre gathers in flocks near the nesting grounds as early as the last week in December. Groups appear for a few hours then disappear again for days or weeks. In the eastern Atlantic murres pay their first visits to the breeding cliffs about the middle of March. During these early stagings they engage in activities of preliminary social importance: they swim in line, fence bill (jabbing) with neighbors, skitter over the surface, dive in unison, and occasionally make reconnaissance or "joy flights" along the cliffs or the shores which later become their nesting site. The murres sometimes fly to heights of over 1,000 meters in joy-flights. Some observers believe that these early season sporting assemblies may promote synchronous reproductive readiness necessary for successful brood-raising.⁶¹³ On cliffs the murre sits facing the wall with its short tail pointing toward the sea. When its young hatches, this position of the adult tends to prevent the young from prematurely plunging to the sea. But the murre also nests on low islands where it packs together wing-to-wing over acres of rock. Under such conditions, with about 500 square centimeters per nest, 200,000 pairs may nest on one hectare. Nesting in such close quarters causes frequent brief squabbles. They jab one another often locking bills and sometimes tumble together from their ledges into the surging sea below. Aggressive jabbing, however, most often gives way to appeasement postures.^{72, 609}

Soon after arrival at the colonies, pairs engage in mutual billing, nebbing neck feathers, and preening. Copulation may take place on the water but most often at the site where the egg will be laid. There always seem to be extra birds ready to grab an unguarded egg site; consequently, once a claim is staked out, it is seldom left unattended.

When prepared to mate, a female squats in a horizontal position with her head directed forward or tilted upward. When the male mounts, she opens her beak revealing the yellow color of her mouth and she tosses her head backward; her tail is erect while she utters ecstatic moans. With his wings fluttering, the male twists his tail downwards until the cloacas meet for sperm transfer, after which they sit preening side by side.

Bowing is a frequently observed mannerism of murres, and mutual bowing, mixed with billing and the displaying of the buccal lining, is also demonstrated by pairs after copulation. Bowing is also an indication of excitement or alarm among murres: any disturbance causes increased bowing.⁵⁸⁴ Perhaps the habit is developed from concern for the egg or chick which is usually protected between the feet. Inspection of the egg or chick would naturally involve a bowing motion. Each female lays a distinctive and colorful egg with varying backgrounds of pale green, blue, ivory, or light sand splashed with blotches of lilac, dark brown or black. The egg is finely tapered and averages about 104 grams which is close to 10 or 11 percent of the female's body weight.⁸⁷

By mid-May most eggs have been deposited. Color variations enable the adult murre to recognize its own egg.⁶⁰⁹ If an egg is left unattended, it may be quickly taken over by a neighboring pair that perhaps accidently lost their own over the edge of the cliff or to marauding gulls. However, such adoption occurs only among immediate neighbors and only if the egg resembles their own. Some eggs actually become glued to the substrate by accumulated coatings of guano, and many are eventually fatally buried beneath this pinkish lime. On Funk Island, Leslie Tuck counted 203 eggs out of the 659 lost by being buried in excrement and water. He also noted that birds nesting in the fringe area around the edge of the colonies attained only a 17 percent hatching success.⁶¹³ If the egg is lost, it may be replaced in fifteen to seventeen days, if it is still early in the season.⁶⁰⁹

Although the female tends to incubate more frequently at night than does the male they more or less equally share the incubation duties for thirty-two to thirty-four days.^{87, 639} For warmth, the egg is tucked on top of the webbed feet against the bare, vascularized incubation patch.⁶¹³ This habit sometimes leads to a hail of eggs into the sea below if the birds are flushed suddenly from their ledges. Eggs are sometimes even blown off ledges in stormy weather. When a murre egg is moved experimentally, the adults, upon returning, seek out their egg and after tucking it on top of the feet and against the incubation patch proceed to move it back to its original position.³¹⁰ Although the egg sometimes lose its shell in the latter stages of incubation, the chick may still complete its development within the tough shell membrane.⁶¹³

The developing murre chick imprints upon its parents and learns their calls while still in the egg. It has also been observed that breathing and clicking sounds of the chick inside the egg stimulates neighboring unhatched chicks to begin the pipping process. The phenomenon apparently facilitates synchronous hatching.⁶¹⁰ The fact that a chick imprints so strongly on its parents also lowers the incidence of communal care of chicks. The chick begs only from its parents unless orphaned. During his study of murres in the Gulf of St. Lawrence, R.A. Johnson reported that he never saw a chick older than four days of age beg from a strange parent, but this does not mean it never occurs.³¹⁰ (Appendix Figure 10 provides data on the growth of young murres and compares them with other species.)

A parent bird demonstrates selectivity when choosing fish for its young. It brings only small fish when the chick is small. It seems to know that small chicks must have only small fish and that larger chicks can swallow bigger ones. In the Atlantic, fish taken by the murre average 15 centimeters in length.^{254, 614}

The murre carries only one fish at a time, directed head inward with the tail dangling from the tip of the bill. Puffins, however, may carry several fish held sideways. A guillemot (Cepphus ) also brings only one fish at a time but holds it by the head with the tail dangling from the side of the bill. When a murre approaches its ledge with food, it makes an audible signal which brings the chick from under the wing of the incubating parent. The parents protect the chick between them, their wings lifted slightly to mantle their brood, and their heads bowed until the chick sees the fish.⁶⁰⁹ The protective hedge thus provided around the chick undoubtedly reduces the possibility of neighboring adults grabbing the food. The female feeds the chick more frequently than the male, but the male invests more time in the overall rearing.⁶⁴¹

At 18 to 25 days of age, depending upon latitude, weather, and food availability, a young murre is ready to fledge to the sea. At this stage, it weighs only one-third its adult weight, and body coverts, although still having considerable down clinging to them, are sufficiently developed to protect the juvenile from the cold sea. However, it cannot fly yet, the wing primaries still being small. Parent birds accompany the young bird over the edge or call to it from the sea mainly during the late evening hours, coaxing it to plunge from the rocks into the sea. The chick responds with a fearful excitement, loud, clear "watercalls," and a bobbing of the head toward the sea. Jeremy Greenwood has described the last moment on the ledge: "Suddenly the chick, stretching a little farther, raises its tiny wings over its back and pushes with its legs. In a fraction of a second it has gone, with the adult almost immediately behind."²²⁶ Chicks even leap from high cliffs and, for some perhaps too young to tolerate the cold water, it is a fatal move, as witnessed by the fact that up to 10 percent may be found floating dead in the surrounding sea the next morning. Occasionally some fall hard on fringing rocks and are killed, but being light-bodied and with the lift provided by their rapidly-beating wings, most descend successfully. It is a risky business all the way from the egg to fledging for surface-nesting alcids, but once safely in the water, a young murre has a good chance of reaching adulthood. Depending upon the nesting locations, chick loss varies from 20 to 40 percent.^{270, 617}

On low-lying islands like Funk, the birds follow traditional pathways over the rocks to the sea. The young walk with the adults in procession at dusk. Even idle birds join in or dash ahead to the sea to call the procession in. Chicks too young to go to sea are often prevented by adults from entering the water and instead are herded back to safety.⁶¹³ The young are convoyed out to sea by their parents where, without a single lesson they dive after fish and fly underwater almost as well as the adults. Fledging sucess in Common Murres is often as high as 82 per cent. ⁸⁷

At sea young murres are comparatively safe from predatory gulls, for a marauding gull cannot follow the underwater dive. Gulls tend also to forage near shorelines, seldom bothering small birds more than a few hundred meters from shore. The young murre is very much more at home in the sea than on land, although as one would expect, some end up in the bellies of large fish. In the Atlantic, angler fish have been known to eat alcids.

Like all members of the family, the murre uses its partly-extended wings in submarine flying. It moves through the water swiftly, its webbed feet trailing behind, acting as rudders in turning. Lowell Spring has presented an interesting study of the wing actions during twists and turns based on motion pictures made of murres in large water tanks.⁵⁷³ A murre is capable of regular horizontal U-turns,vertical "head-over-tail" turns, and hovering (see Figure 4). Hovering in water is useful when seeking prey which hides in crevices near the bottom. In the air, the adult murre can attain speeds up to 75 kilometers per hour.

After breeding, the adult murre is flightless for at least two weeks due to the postnuptial molt, during which it continues to accompany its young by drifting with the currents or swimming against it. By the time winter storms begin, old and young have grown their flight feathers and are able to seek favorable conditions on the wing. In areas where they are not forced by winter conditions to move, murres are more or less sedentary, although juveniles are apt to wander far and wide after they become strong fliers.

The murre is not as pelagic as the puffin and it tolerates warmer surface waters to at least 15° Celsius. In the Pacific it is abundant in winter off the shores of central California, and in the Atlantic it frequents the shores of Morocco and the Canary Islands. In brief, the murre is an opportunist even in winter: it moves to where suitable feeding conditions are available away from the areas blocked by ice. Occasionally it is driven toward land, and on rare occasions, winds have been known to blow it to inland waterways as far as the Great Lakes in North America. However, much of what is written about the winter activities of the murre and other seabirds is largely speculative. So few actual documented observations are made during winter months that we are confined to "perhaps and probably". Arctic breeding locations are usually adjacent to winter open water areas called polynyas where birds can survive. Otherwise to keep itself from being frozen in the Polar Basin, the bird would have to migrate to regions of relative warmth. Sudden cold spells are not as much a problem for Thin-bills which tend to range further south, as they are for the Thick-bill Murres.

Records from banding recoveries have been some help in obtaining empirical data, but the recovery of banded birds is slight compared to the large number banded. Although one may expect only about a 2 percent recovery rate, these returns, along with direct observation, give us some indication as to the probable movements of the species in winter. Leslie Tuck observed that in the Newfoundland seas, the murre is not usually found within 6 kilometers of the shore in winter.⁶¹³ However, at Pacific Grove, California, in early January many murres may be seen flying by just outside the breakers, nor are they uncommon in Monterey Bay during the winter months. Further north, along the inside waterways of Puget Sound and Georgia Strait, murres are frequently seen all winter.

In winter, the diet of murres on the Atlantic coast is 92 percent capelin. Exploitation of capelin by fishing industries on the Grand Banks and other areas, may spell trouble for the murres and puffins which depend heavily on this fish.⁴³⁴ Because murres tend to congregate in large flocks in feeding areas while other alcids tend to spread out, they are particularly susceptible to oil spills and to being caught in nets set for fish.

It is generally thought that the young murre first returns to the breeding grounds when about three or four years old. Perhaps some return earlier to observe the reproductive process from the loitering areas around the colonies. Loitering areas for off-duty rest periods away from the crowded incubation area, are also essential for the mature bird's physical well being.⁶¹³

Shameful stories have been written concerning man's exploitation of murre colonies without regard for conservation. The episodes have been especially appalling on both the east and west coasts of North America as exemplified in the histories of Funk Island and the Farallones. Because of egging on the Farallones between 1850 and 1880, the murre population was reduced to one-third its original size, and even though collecting was outlawed there at about the turn of the century, the murre population continued to decline. During the height of the egging, according to early records, an average of 600,000 eggs were harvested annually.¹¹⁴

In the Gulf of St. Lawrence, eggers removed 750,000 eggs annually from colonies along the northern shore of the estuary and by the end of the last century practically all colonies had been exterminated.⁶¹³ Even though they have been protected since 1920, the bird has made little or no recovery.⁴³⁴

In Newfoundland about 450,000 murres are still shot annually for sport and food.434 This is an increase over the 200,000 taken in the early 1950's. In England, the whites of murre eggs were once used to create the glossy surface of patent leather, and in Norway the yolks were used in the manufacture of soap.⁶¹³ Fortunately, bird colonies are not exploited for these purposes today.

On the Faeroes, it has been shown that, when treated as a natural resource and harvested carefully, murre colonies can tolerate limited exploitation. There was apparent decrease until recently in population sizes in the Faeroes after centuries of collecting. As many as 80,000 eggs of murres may be gathered in a week during the season and about a half million puffins are harvested annually. The meat is eaten, the eggs preserved for winter stores, and the feathers are used for pillows and quilts. Possibly owing to other causes, the murre population on the Faeroes has decreased by 10 percent in the last ten years. It has long been known that murre eggs contain more food energy per kilogram than beef or chicken meat. Perhaps if harvested scientifically, the murre could contribute in a limited way to the nutritional needs of mankind. I suspect, however, that the bird's reproductive potential is not that great. Since only one egg is normally laid and only one replacement made each season, there is little doubt that the species would be better off without man's predatory practices.

Where protected, some colonies have increased. In the Soviet Union, recently protected colonies have multiplied more than 25 percent in less than three years. Baltic flocks reduced to 20 birds in 1880 recovered completely when protected, to 15,000 in sixty years. Between 1936 and 1958 on Funk Island, the murre population increased from 10,000 pairs to 350,000 pairs, probably because cod fishing left more capelin for the birds.⁶¹³ The number has now reached 500,000 pairs but there is danger that alcid populations could crash because of present harvesting practices of capelin.⁴³⁴

Storms occasionally kill huge numbers of murres. An aerial survey after a five-day storm in the Aleutian Islands in 1970 revealed more than l00,000 dead murres scattered along a 725 kilometer section of coastline.³²

Chemical pollution is also a problem. We live in an age of plastics, and plastics are taking their toll. As some plastics decay or are burned, toxic chemicals known as polychlorinated biphenyls (PCBs) float off into the air to be deposited later on vegetation and on the surface of the sea. These substances subsequently accumulate in the organs of animals. Murres dying in large numbers have been tested for PCBs and have been found to contain over twice the amount found in healthy birds, indicating a strong possibility that PCBs may be responsible for the deaths.^{89, 91, 297, 472} It has been said that man should return to a completely agronomic society in order to save the world from destructive pollutants. Though this is highly improbable we, nevertheless, could dispose of our wastes in sensible ways. Considering all the facts, murres and other seabirds have plenty to contend with in order to maintain their status quo.

Fig. 4. Underwater motion of turns made by a Thin-billed Murre. The diagrams indicate three different types of turns executed by a murre in an aquarium as analyzed by a motion picture camera. 1. horizontal turn. 2. A half twist downward. 3. An almost complete somersault. The figures indicate the amazing agility and co-ordination of every body part in making the manuevers. Webbed feet act like rudders and the wing feathers bend and twist to provide control. Figures after Lowell Spring, 1971 (Used with permission).