Scientific name:Cepphus columba
Alternate name: Sea Pigeon
Aleut: Seemluch
Japanese: Umibato
Russian: Svistun; Kajurka

Although the Pigeon Guillemot is conspicuous all along the Pacific coast of North America, it does not congregate or nest in the spectacular numbers of some of the other alcids. It is limited instead to areas where a nook under a rock or a hole in a sandy cliff can provide shelter for a nest. More recently, it has adapted to man-made structures, nesting on the timber supports of docks, for instance. At Depoe Bay, Oregon, at least six pairs use the concrete ledges of the highway bridge that passes over the narrow entrance of the bay where human traffic is constant. At least a dozen pairs breed just a few feet from the beach on Battle Rock at Port Orford, Oregon, where their entire breeding cycle and behavior can be easily followed by interested observers.

While the species ranges around the north Pacific from the Santa Barbara Islands to the Kuril Islands, nobody has yet made an accurate estimate of their total numbers. We may assume that if there are 1,000 individuals for each hundred miles of coast, then 7,000 miles of coast might have 70,000 Pigeon Guillemots. Alaska alone has almost 34,000 miles of coastline: although not all is suitable habitat, there is ample room for a quarter million birds. Counts at known colonies in Alaska total 40,600 while the estimate for the state is 200,000. 570 About 2,000 birds inhabit the Farallon Islands, California near the southern extent of their range.⁴

Nonbreeders, possibly birds too young to breed, mix with breeding pairs, especially from dawn until about noon. Deferral of first breeding until about three or four years of age is the rule.⁴²² Depending on the nesting sites available, groups of three or four to twenty or more pairs may be seen in suitable and traditional areas accompanied sometimes by as many immature birds. Although these congregations appear early in spring, they seem to be in no hurry to lay eggs.

Because Pigeon Guillemots are limited by available nesting places they are flexible in their choice.¹⁷⁹ Practically every conceivable situation is used: rocky crevices, ledges with little shelter, burrows in sandy cliffs, under logs or rocks at the edge of islands, or under dense, matted vegetation. However, they prefer the rocky crevices or a position under a boulder. Cavities may be occupied for more than a month before the eggs are laid during this time the pair clears the cavity of debris and perhaps gathers small chips of rock to provide a base for the eggs. No additional nesting material is used and eggs may even be found laid on bare soil. The chief nest-selection criterion seems to be the need for at least a partial shelter overhead.

Unlike the puffin, which is a relatively silent bird, the Pigeon Guillemot engages in numerous vocalizations, variations on two themes described in several ways by different authors: (1) in an undisturbed group of active birds, the most common sound is a short "whist" (chip) or "tsip," (seep) and (2) upon approach of an intruder or a disturbance such as a passing boat, the warning or alarm scream "seeeoo" is rendered from an alert posture with the head raised, or in flight during a fly-by. The alarm is infectious, one bird alerting the others which also begin screaming. The sound is best imitated by a person whistling through the teeth. These two basic calls are used in varied combinations to produce all of the other vocal signals used in social activities.^{584, 604}

There is the twittering combination of the "whist" used by a pair of birds engaged in billing, and the long "trilled song," a type of greeting or recognition sound used between pairs or toward their young. This "trilled song" can be described as "sit sit sit seeoo, sit sit sit seeoo," the "seeoo" involving a rising and falling in pitch.⁵⁸⁴ It is a private family communication: when a guillemot utters this trilled song, the only response seems to be from the mate or the young in the nest. Douglas Nelson who studied in detail the vocalizations of Pigeon Guillemots suggests that is is to advertise territory ownership over long distances. ⁴²¹ Sometimes when a parent approaches the nest with food, it pauses close to the entrance of the nest, leans forward, stretches the neck and sings several bouts of this trilling call. Upon hearing their parent, still out of sight, the young begin a constant "cheep cheep cheep" but no sound can be detected from neighboring nests. The young, therefore, appear to recognize their own parents' voices. However, food is most frequently delivered without any ceremony. At other times the bird may deliver the fish, come out of the nest cavity, then utter a trilled call with no response from the chicks. This seems to proclaim territory and may encourage the mate to bring food. On one occasion one parent bird after trill-calling was seen to take a fish from its mate's bill and fly directly to deliver it to the young in the nest.⁶⁰⁴ Variations of the "trilled song" are made while mated birds are swimming close to each other on the water or sitting close together upon the shore. The song in these instances ends in periods of billing. It appears, then, that the "trilled song" may have three functions: to stimulate feeding, to assist in preservation of the pair bond, and to declare territory.

Even novice observers of Pigeon Guillemot behavior soon notice that groups swimming on the sea form lines and arcs. Line forming is common to several species of alcids. It is apparently a passive formation due to currents, wind and the spacing requirements of the birds themselves. When the space between birds is reduced, adjacent birds may aggressively strut and lunge at each other, beginning a chain reaction of fighting, splashing, skittering, shallow underwater chases, and aerial pursuits. This has been called the "water dance."¹⁶⁵ It is really not a dance like the dance of a crane or a grebe which involves action with the feet. Perhaps a better term is "water sporting." It is a very aggressive splashing with the wings, amusing to watch but confusing to interpret. The action usually ends as quickly as it begins, but not before the birds have dispersed. Gradually the lines reform and the action soon starts all over again.

On land, perching sites are aggressively defended. The aggressor struts with its tail cocked and with its wings partly spread, then lunges toward its opponent. Both male and female defend the position next to a mate from intruding birds. The lunge is a forward jab or aggressive peck toward the opponent and often ends in a wing-beating fight and a tumble to the water below, where an underwater chase follows. In the water they thrash and turn, each following the red legs and the white flashing wing patches of the other. In the air they reel and turn, swoop upward, make contact, and crash together into the sea where they skitter and splash until one gains adequate distance from the other. These aerial pursuits have been called "duet flights."¹⁶⁵ A better name is "duel flights" since the actual flight involves fighting not singing.⁶⁰² The pursued bird, in its attempts to throw off the chaser, makes sudden 90 to 180 degree turns in water or air. Within a few minutes after the end of a fight, they are both back peacefully occupying their positions on the rocks below the nesting cavities.

Sea pigeons are noted also for their unaccountable group flights around their territory. A group calmly sitting on shore suddenly takes to wing, flies a circle or figure eight once, twice, or three times, then lands again to shuffle, each for its original position on the rocks. Flying in circuits is also frequent: before delivering food to its nest, a bird will circle to check whether or not it is safe to approach the nest. While I was weighing a pair of chicks on Deception Island, a parent approached carrying a fish without first circling. At the last split second before landing at the burrow entrance, it spied me at the top of the bank among the salal bushes. It uttered a short, fearful cry, dropped the fish, and literally fell out of the air into the surge below. Upon surfacing, it skittered seaward to a safe distance, confused as to whether it should dive or fly to escape. One would guess that the next time this bird might approach its nest more cautiously.

Mated birds are affectionate pairs. Whether on the water or resting on land they spend considerable time billing, nebbing, twittering, circling, and trilling to each other. Copulation always takes place on land not far from the nesting nook, and it is heralded by the male "circling" while the female crouches with her tail up, her bill open revealing the bright red mouth and head thrown back in an "ecstatic display" similar to that seen in the Razorbills. During the actual copulatory act the female is passive most of the time, and in some cases she ends the act by rising and throwing off the male. Successful copulation ceases after the eggs are laid.¹⁶⁵

But this ecstatic display apparently is not necessarily associated with copulation, nor is it performed only by the female. This display is similar to, or maybe synonymous with, the "hunch-whistle," described by some observers as a form of aggression.^{165, 420} The hunch-whistle is often displayed when an intruding bird ventures too close to or between a mated pair. In these instances the display appears to be a signal of mated status. If the intruder remains, aggressive action in the form of "twitter-waggle" occurs, involving one or both mated birds drooping their wings and lunging toward the intruder. (See the Black Guillemot's "head-shaking," Chapter 7 and Table 10 in the appendices). The hunch-whistle exhibited by a single bird usually brings the mate to the scene to help drive off an intruder. The hunch-whistle also occurs when an unmated male attempts to mount a female by rushing her without the proper precopulatory procedure. In such instances the attacked female will move away from or lunge at the male. Douglas Nelson, who has studied their behavior probably more than anyone else, describes the hunch-whistle as entirely aggressive and exhibited mostly by males.⁴²⁰

"Twitter-waggle" is displayed on shore or sea. In this action the wings are drooped, the tail cocked and the head and neck outstretched. The crown feathers are erected, the head waggled from side to side with the bill opened producing an excited twitter. This can be an appeasement action often exhibited by an intruder (as in the sense, "let me stay") or the preliminary warning of the aggressive lunge in defense of position (as if to say, "This spot is ours, you get out.") Only rarely is it seen between mated birds.^{165, 584, 604}

Billing only occurs between mates. Rudy Drent has very aptly described this action.¹⁶⁵ "Whether on the water or ashore, the participants twist the head so as to direct the bill at that of the mate. A slight but definite waggling motion ensues, but the bills rarely touch, their tops continually passing and repassing one another. This movement is accompanied by a gentle twitter 'sit sit sit' punctuated at intervals by the 'trilled song' . . ."

Now that the birds are mated, the female is ready to lay her eggs in the prepared nesting cavity. A young female tends to lay only one egg while a more mature bird lays two. In rare instances three eggs have been found, but these are likely to be the contribution of more than one female.¹⁶⁵

Generally the two eggs are laid three days apart and incubation, shared variably by both males and females, lasts between thirty and thirty-two days. The eggs can stand short periods of cooling, even wetting by rain. As long as nothing moves the eggs from their original position, the owners will continue to incubate them. One morning, I found a set of eggs flooded by rain water on Williamson's Rocks, Washington, seven days prior to hatching time. In this instance the water seeped away quickly, leaving the eggs in their original position and allowing the adults to return to hatch them successfully. Another set was displaced about 15 centimeters by water and was consequently rejected. Incubating birds commonly leave the eggs periodically to bathe, preen, drink, and defecate. These interruptions are rarely longer than ten minutes, and usually they do not leave to feed until relieved by the mate.

In the San Juan Islands area, the earliest known egg-laying date is 18 May and the latest 29 June. However, these limits are apt to vary from year to year according to early or late spring weather conditions. It also appears that each female has her own egg-readiness period. In other words, the early egg-layers tend to be first every year, and the later ones characteristically late.

Pigeon Guillemot eggs vary in color from faintly marked creamy-white to heavily blotched greenish-gray. The blotches vary from black to dark brown to underlying patches of olive, drab gray, or lilac. All colors may be represented in a single egg while others are almost entirely white. Pigment patches may be limited to one or two large spots of dark brown. Others lack markings but show light lavender spotting below the surface layer of the shell.

Of seventy-eight eggs studied in the vicinity of the San Juan Islands, 46 percent failed to hatch. Because of frequent human disturbance at one colony in the same area, 63 percent failed to hatch. Here unbroken eggs were found on the sand below the bank where several burrow-type nests were located. When these eggs were replaced in the nest the birds rolled them out again. Either they recognized that the eggs were inviable or a new pair had taken over a deserted nest.⁶⁰⁴

At hatching the chick wears a thick coat of black down. After it has dried completely, it is a beautiful creature with alert beady eyes, pinkish feet and a prominent white-egg-tooth on the tip of the upper bill. It defends itself courageously with a strong impulse to peck which at the same time reveals the flesh-pink interior of the mouth.

Approximately twenty-four hours after hatching, the chicks are fed for the first time and development progresses rapidly. A parent bird stays with them day and night for three days, by which time temperature regulation is established. Once feeding begins, the chicks average 10 grams gain in body weight per day. The hatching weight of 29 to 50 grams is about 7 to 12 percent of the adult weight of 400 grams, which the chicks attain by the time they are thirty-three to forty days of age.

Both parents feed the young. For the first few days, considerable selectivity in the size of the fish is seen, the young being offered only small fish about 5 centimeters long. As the chicks grow the parent birds show less selectivity in the size of fish. Slender fish up to 18 centimeters long may be delivered and occasionally more than one fish may be carried. In the San Juan Islands area, a variety of species are used for prey. These include lamprey eels, stickleback, shiners, sand lance, various species of blenny eels, rockfish, sculpins, flatfish, and others. However, blennies and sculpins make up at least 70 percent of the fish delivered. ¹⁶⁵ On the Farallon Islands, records of twenty-four species of fishes, representing nineteen genera and ten families are preyed upon by Pigeon Guillemots.¹⁹² In other words, sea pigeons are opportunists, catching any slender fish of appropriate size to be found in littoral to benthic zones. The species of fish most commonly preyed upon are bottom dwellers. Unlike other alcids, guillemots use their feet as well as their wings for underwater motion. Use of the legs facilitates catching bottom dwelling prey.¹⁷³

The process of fish delivery usually lasts only a few seconds. The chick snatches the fish and swallows it head first with several gulps, then with a couple of satisfied cheeps it settles down to digest its meal. Extra-long fish may cause a chick to choke to death. Rudy Drent reported that a chick, almost old enough to leave the nest, choked to death on an oversized blenny. The fish was so tightly lodged that it could not be removed without slitting the young bird's throat. He also reported that a chick often rejects food brought by its parents. The most commonly refused fish are flatfish, which are too wide to swallow.¹⁶⁵ The young bird apparently has to learn to fold flatfish lengthwise before they can be swallowed. Adult birds carrying flatfish usually have them folded.

As chicks get older feedings become more frequent.^179b At three to five days of age, each chick may be fed only six or seven times a day. By Day 31, twelve to thirteen fish are swallowed. On the average, each chick consumes about ten fish per day. Bones and all are digested, and the feces are very liquid. Based upon ten meals of 10 to 12 centimeter sand lances weighing an average of 6.5 grams each, an approximate total weight of fish delivered each day is 65 grams. Activity of the young between feeding times is minimal and limited to sleeping, sitting, standing, defecating, preening, and stretching the wings when they have room to do so. Aggressive action between nestlings is rarely seen, although one observer suspected sibling cannibalism by a nestling Pigeon Guillemot.⁵⁰¹

By Day 20, more than half of the down has been replaced with contour feathers, giving the chick a rather shaggy appearance. It is now a mottled dark gray and white; the head, nape, wings, and dorsum being darker and less mottled than the breast, belly, and flanks. Often white feathering extends around the neck and lower cheeks. By Day 27 the egg-tooth has worn off and the juvenile has attained a sleek and trim appearance. All the young have left the nest by the time they are thirty-three to forty days old. (See the Appendices for a table of measurements of chicks compared to adults as well as a graph of growth rates. Table 10 and Figure 11).

When old enough to leave the nest, the young bird is on rare occasions coaxed out to the entrance with food.⁶⁰⁴ This has also been described in the Black Guillemot.⁶⁶³ While watching a nest in a sandy bank previously excavated so as to permit observation from the rear, I saw a juvenile coaxed from the burrow, an older chick already having left the burrow. This second juvenile, thirty-seven days old, was enticed to come to the burrow entrance to receive food by much twittering, trill calling, head swaying, and peering. But the parent did not release the fish until it had worked its way between the young and the nesting chamber, exposing the young one to the entrance while the vocalizations from the parent continued. The chick secured the fish, swallowed it, and after a nudge or two from the parent, the young bird dropped through the entrance and flew rather erratically and unstably to the water about 50 meters away. Once in the water, it splashed and dived, all the time making its way further out to deeper water using its wings instinctively to propel itself under water.⁶⁰⁴

The parents return to the nesting area for some time after the last chick leaves. They may even continue to bring fish to the nest cavity, and when not received, will swallow it or drop it near the nest entrance.¹⁶⁵

Once in the water, the juvenile becomes independent of its parents, although young birds may group together in small numbers to feed. Within two weeks of leaving the nest, it is able to fly well. In the San Juan Island region, young birds may be seen in the breeding vicinity after all of the adults have left the area in mid-September. In the Spring, yearlings may also be encountered among the nonbreeders around a nesting area and can be recognized by a few remaining white feathers on the breast and belly. The white wing-patch of the breeding plumage is also not as well-defined in the young bird as it is in adults. They probably do not breed until they are three or four years of age, but no information is available to precisely indicate this.

Fully developed, Pigeon Guillemots are excellent flyers. Broad wings allow for good maneuvering as demonstrated in their aerial chases and quick turns. In a good wind the bird even glides well. On the Farallon Islands, California, where the wind frequently blows at 30 knots, Pigeon Guillemots sport in the wind. I have seen them gliding down the leeside of the island, then laboring hard against the wind to regain the crest, turn, and glide again in a form of play. (For a summary of Behavioral Displays seen in the Pigeon and Black Guillemots, see Appendices, Table 10. Table 7 compares Guillemot extremities).