U. aalge Skull Replica or Common Murre measures 4.4 inches, museum quality polyurethane cast. U. aalge Skull Replica is 2-part skull (separate cranium and jaw). Made in USA.
The Common Murre or U. 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.
The Common murre mainly eats small schooling forage fish 8 in. long or less, such as polar cod, capelin, sand lances, sprats, sandeels, Atlantic cod and Atlantic herring.
Capelin and sand lances are favorite food, but what the main prey is at any one time depends much on what is available in quantity.
It also eats some molluscs, marine worms, squid, and crustaceans such as amphipods. It consumes 1 1⁄16 to 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.
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.
U. aalge or Common Murres are fast in direct flight but are not very agile. They can maneuver better underwater, where they typically dive to depths of 100–195 ft. Depths of up to 590 ft. have been recorded.
They are a pursuit-diver that forages for food by swimming underwater using its wings for propulsion.
The breeding habitat is islands, rocky shores, cliffs and sea stacks. The population is large, perhaps 7.3 million breeding pairs or 18 million individuals.
Allopreening is common both between mates and between neighbors. Allopreening helps to reduce parasites, and it also has important social functions. Frequency of allopreening a neighbor correlates well with current breeding success.
U. aalge 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.
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.
U. aalge or Common Murres breed in colonies at high densities. Nesting pairs may be in bodily contact with their neighbors. They do not make a nest; their single egg is incubated on a bare rock ledge on a cliff face.
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 to10 minutes.
The eggs vary in color and pattern to help the parents recognize them, each egg’s pattern being unique. Colors 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. 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.
Eggs hatch after about 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.
Common Murre or U. aalge 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.
Both male and female Common Murres moult after breeding and become flightless for 1 to 2 months. Some populations have short migration distances, instead remaining close to the breeding site year-round.
