Last week, I posted about the two species of puffins we see in Alaska. These are the horned puffin (Fratercula corniculata) and the tufted puffin (Fratercula cirrhata). This week I’ll describe puffin nesting behavior and other facts about these interesting birds.
On Kodiak, puffins arrive at their breeding colonies in May. Breeding colonies are usually on cliffs along the shoreline or on small islands. The steep nesting areas not only help protect puffins from predators but provide a good take-off perch for these heavy birds with small wings. Horned and tufted puffins may nest in the same colony, and they sometimes also share nesting grounds with other alcids, and with glaucous gulls, glaucous-winged gulls, kittiwakes, and cormorants.
Puffins are monogamous and form pair bonds that last many years. Courtship takes place soon after they arrive at their breeding grounds. Mates sit on the water, and the male lifts his bill straight up while opening and closing his mouth and jerking his head. The female hunches over close to the water while keeping her head and neck close to her body. Then, the two birds face each other, waggle their heads and repeatedly touch bills while opening and closing their mouths.
Puffins nest underground. They have sharp claws on the toes of their webbed feet that they use to scratch out deep burrows, measuring three to four feet (1 m), into the steep hillside. At rocky sites with little soil, puffins nest in rock crevices or on cliff faces. Puffins may line their nests with grass, twigs, feathers, or even manmade materials. Mates often use the same nest year after year and may lengthen the nest each season. A female lays only a single whitish-colored egg, and the male and female take turns incubating the egg for 42 to 47 days. The parents put all their energy into this one offspring, and because of this, the success rate is high for a puffin chick to survive until it fledges. In a study, biologists determined 65% of the tufted chicks and 60% of the horned chicks in the study group survived until they left the nest.]
The chick hatches in July or early August. At birth, it is covered with down and its eyes are open. Parents take turns booding the chick until it can maintain a body temperature of 103.1⁰ F (39.5⁰ C); this usually takes six days. The chick remains in the burrow for the next 45 to 55 days, while the parents take turns watching and feeding it. The parents feed the nestling by catching small fish in their bills and dropping them on the ground in the nest or near the entrance of the burrow. When it is weaned, the chick leaves the nest between dusk and dawn to avoid predators. It cannot fly well at this point, so it either walks or flutters to the ocean where it remains. The parents do not accompany the chick, but they also leave the nest around this time. Young puffins head to the open ocean and remain there through their first summer. When they are two-years-old, they visit the colony during the summer. They are old enough to breed when they are three, but they are not certain to breed until they are four-years-old.
Not much is known about the lifespan of Pacific puffins, but they are believed to live 15 to 20 years in the wild. Tufted puffins have been known to live 25 years in captivity, while an Atlantic puffin survived 39 years in captivity.
With its heavy body, short wings, and webbed feet, a puffin is built more for swimming than for flying. A tufted puffin is the size of a crow but weighs twice as much and has short stubby wings. It must beat its wings 400 times per minute just to stay aloft. Not only is it difficult for a puffin to take off from the water and gain altitude, but it lacks maneuverability in the air, and crash landings and mid-air collisions between puffins are not uncommon. When a puffin takes off from the water, it usually remains close to the surface for a ways and may even hit the water with its wings and bounce off the waves to gain altitude. When flying, a puffin uses its feet to change direction. A puffin is much more graceful in the water, and when swimming, it uses its wings for propulsion and its feet for steering. On land, puffins walk in an upright position, using their claws to cling to slippery rocks and rough terrain.
Fights between puffins are common and occur when one puffin perceives another is invading its territory. The resident puffin threatens the intruder with an open bill that exposes its brightly colored mouth lining. It also shakes its head, jerks its head upward and back, and rocks its body from side to side.
Puffins feed in small flocks and can dive as deep as 262.4 ft. (80 m) to catch their prey. They feed on lipid-rich fish such as sand lance, capelin, and herring, and they also eat euphausiids (krill). When catching fish to take back to the nest, a puffin can carry a large number of fish crosswise in its bill with the heads and tails dangling from the sides of its mouth. It can hold several fish in its mouth and continue to catch more fish without losing any of them due to spines on its tongue and on the roof of its mouth that act as hooks to hold onto the prey.
Surveys in Prince William Sound suggest the horned puffin population in that area declined 79% from 1972 to 1998. Biologists believe this decline in numbers is due to major changes in the food base as a result of global warming. This fall, the bodies of 217 dead tufted puffins have been recovered on St. Paul Islands in the Pribilofs, and biologists have determined that the puffins starved to death. Their deaths, like the earlier deaths of horned puffins in Prince William Sound, were blamed on a shortage of food linked to higher-than-normal ocean temperatures in the Bering Sea. Biologists believe thousands of tufted puffins may die in this region this winter.
Puffins need a predator-free nesting area and an abundance of food. They are subject to predation by foxes, river otters, rats, eagles and other birds of prey. Ravens may attack nesting chicks. When traveling from the winter feeding area to their nesting grounds, puffins fly in large groups in a pattern that resembles a wheel, making it difficult for an eagle to attack an individual bird. Puffins are susceptible to oil pollution. After the Exxon Valdez oil spill, 162 dead horned puffins and 570 dead tufted puffins were retrieved from the oiled waters, but biologists believe several thousand puffins were killed by the spill. Puffins are also often caught as bycatch by gillnet and driftnet fisheries.