Scientific name:Fratercula corniculata
Aleut: Kageethah
Japanese: Tsunomedori (Horn-eye Bird)
Russian: Tupik, Toporik, Ipatka St. Lawrence Island: Kupruwuk

The Horned Puffin is primarily a bird of Alaska and the Bering Sea, extending its breeding range to northeastern Siberia and south to Forrester Island and Glacier Bay, just north of the borders of British Columbia. There is no known breeding location for this species in British Columbia, although it is frequently observed south of the Queen Charlotte Islands during the summer months and occasional sightings are made along the Oregon and Central Californian coasts in July. 276, 548

To the casual observer, a Horned Puffin may be mistaken for the Atlantic species, but it differs in several respects. It is a larger species and the bill differs markedly in shape and color. The eye markings are more pronounced and a strange, fleshy horn extends upward from the eye, giving the species its name,Fratercula corniculata. The male and female are identical in appearance.

Although it occasionally digs burrows like the Atlantic and the Tufted Puffin, the Horned Puffin primarily nests in rock cavities. ⁶⁴⁹ Arrival at the nesting grounds on islands in the Bering Archipelago peaks during the first week of June, and egg-laying extends to the end of the same month. ⁶⁴⁶ On Chowiet Island, Alaska, eggs were laid from 14 June to 9 July. ¹¹⁷ On Forrester Island, at the southern extent of its range, one might suspect slightly earlier egg dates.

It is not nearly as abundant as other puffins, totalling probably not more than 1,500,000 individuals. The Kodiak area of Alaska has 287 known colonies with at least 593,450 birds, creating the main center of distribution for the species. Of this number, 194,000 breed in the vicinity of the Semidi Island. ⁵⁷⁰ Over part of its range it is sympatric with the Tufted Puffin, even frequenting the same colonial area, although the Horned Puffin inhabits rocky parts. Nevertheless, the two species do occupy different niches. Foods, feeding times, and main feeding areas differ, despite some overlap.

Horned Puffins tend to feed close to shore in the tide rips of the littoral zone in and around the kelp beds. In the summer months, at least, feeding is concentrated, within 2 kilometers of their breeding sites. ⁵³¹ Like all seabirds the Horned Puffin is an opportunist, taking whichever prey is most abundant. Early in the season, when reproductive behavior makes polychaete worms plentiful, the Horned Puffin feeds upon them freely. Squid is also eaten, but while rearing young, slender fish such as Atka mackerel, capelin, sand lance, and Pacific cod comprise 85 percent of the diet. ⁶⁴⁹

An unfortunate phenomenon related to feeding is the high incidence of plastic fragments found in the intestines of puffins and auklets. Out of sixty-five puffin stomachs examined near Buldir Island of the Aleutian chain, thirty contained plastic fragments, of which eleven had only plastic, with no food items at all. ⁶⁴⁶ Other research records similar incidences elsewhere in the world. ⁴⁷⁰ It is thought that some of this plastic pollution may be ingested secondarily, having first been swallowed by prey organisms. Regardless of the source it is sufficient indication that man positively must stop dumping debris into the sea.

Michael Amaral, who studied the Horned Puffin on the Barren Islands, Alaska, observed courtship behaviour taking place among large rafts of birds on the sea, within easy view of land, between 29 May and 18 June.⁷ As with other puffins, it comes and goes from its breeding ground in irregular cycles, sometimes spending three to five days on the islands, and then leaving for an equal period. After about three weeks, it comes daily with greater regularity, and then egg-laying begins. Snow melt influences the time of laying on St. Lawrence Island, but cliff nesters get an early start. Both male and female take part in incubating the single white egg which is laid upon grasses and a few feathers gathered as nesting material. ⁵³¹ This habit of gathering nesting material sets the Horned Puffin apart from the other species which tend to lay their eggs upon the bare substrate.

The body weight of the adult varies from 435 grams to 754 grams, with an average of about 610 grams. In 1973 Spencer Sealy found that the birds on St. Lawrence Island lost less than 5 percent of body weight during the breeding season. ⁵³¹ This indicated a plentiful food supply that year and that little energy was expended in procuring it. By comparison, in studies of the Atlantic Puffin, Belopol'skii discovered almost an 11 percent loss in body weight. 61 It is obvious that food supplies vary with location and year, a factor which must be considered for a complete understanding of seabird requirements. The average egg weight on St. Lawrence Island is 57 grams, or 9.5 percent of the female body weight. ⁵³¹ Horned Puffins have two brood patches during the incubation period, which heats the single egg more efficiently by contacting both sides of the egg. The body temperature of adults averages 40.1° Celsius and the temperature at the brood patches is about 2° Celcius cooler. ⁵³¹ The incubation interval is 40 to 43 days with an average of 41.4 days. ⁵²⁷

The chick may be left alone in its burrow after Day 6 at which age it can maintain its own body temperature. The egg-tooth which protects the soft bill during the hatching process may persist until Day 29. This feature may be of value in estimating the age of a chick. Both parent birds cooperate in feeding the chick for thirty-six to forty-two days. The chick at this age has reached about 68 percent of its adult weight and is ready to fledge. ⁵³¹

Monitoring of Horned Puffin eggs on islands in the Lower Cook Inlet of Alaska in 1978 revealed that 25 percent of the eggs laid failed to hatch. But in the same locality and season, less than 8 percent of the chicks which hatched, failed to mature. This sample means that in 1978 on islands of the Lower Cook Inlet each pair of breeding adult birds successfully fledged only 0.6 chicks. ³¹⁷ In other words, it took ten adult birds to rear three young to the fledging stage. We do not know how many young birds survive the four to five years it takes to reach breeding maturity. Assuming that these figures are an average for the Horned Puffin, each adult bird would need to survive for about 8 years and breed for at least four in order to maintain population stability. Possibly, 1978 may have been an unusually poor year for breeding success at the colony studied, since at other localities the previous year, fledging success as high as 91 percent were recorded. ⁶⁴⁹ Fortunately, as has been found with the Atlantic species, the puffin may have fifteen or more reproductive years.

By the end of the first week in September, all young have fledged from the northern colonies and gone to sea. Although considered by some to be less pelagic than the Tufted Puffin, Horned Puffins have been observed scattered over wide areas across the Pacific Ocean. ^{11, 239}

The adult bird completes a postnuptial molt in November to December after which it is marked like the young bird, although the bill of the latter is less deep, less arched and lacks grooves or ridges. The yearling's bill is brownish, lacking the reddish tinge of the adult. Although subadults are sometimes seen near the breeding grounds, the Horned Puffin seldom comes to land until ready to breed. ⁵³¹ (See the Appendix, Figure 14 for growth comparison between Tufted and Horned Puffins.)