The first complete survey of the active volcano, Bogoslof Island, was accomplished from the ship Discoverer, H. B. Campbell, Commanding, during the 1935 season. The following paragraphs are from the Descriptive Report of the topographic survey.
Bogoslof Island consists of two islands, the main island and Fire Island (first called Grewingk) connected by a rocky bar which bares in spots at mean lower low water. Fire Island resembles a medieval castle which rises nearly perpendicularly from the water. The “mainland” consists of Castle Rock, the Plateau, and the Volcano. Castle Rock (pinnacle rocks) has two summits, sharp in outline rising at the southwestern edge of the plateau. The plateau ends in a vertical cliff along the beach but breaks away in a series of steps to the north. The volcano, a rounded mass of lava, is northwestward of Castle Rock.
Both Fire Island and Castle Rock are beginning to disintegrate and the movements of the nesting fowl start minor rock slides from time to time. The volcano is of more recent formation (reported by the Coast Guard cutter Northland in 1927). It is a mound of porous lava rock or cinders, 140 feet high, that has weathered but little and is still sharp and rough. Steam mixed with a trace of sulphur fumes issues gently from cracks near the top of the volcano. In a few places the rock feels warm to the touch.
The pond at the base of the volcano is salt water with some sulphur in it. The surface is 4 feet below high water, but a very high tide will cause the pond’s surface to rise about a foot. This height is not reached until several hours after the time of high tide. A very low tide does not affect the elevation of the pond. Gas from the volcano bubbles through the water near the southern shore of the pond. This gas has no odor. The surface temperature of the water measured several times during June, July, and August was 68° F. This is several degrees warmer than the sea water and much warmer than the average air temperature. On the warmest days all members of the party went in swimming. The bottom drops away from the shore at an angle of about 60°. There is a large amount of driftwood scattered along the shore of the pond. This undoubtedly was washed there during an extremely high tide when the water covered the low sand barrier between the pond and the sea.
The plateau of the island is a mixture of black sand, lava dust and cinders, and rock.
The beach is black sand except along the northern spit, where it is pebbles and small bowlders, and around the volcano, where it is rocky. The sand is unstable and shifts with the sea. The spit on the southeast end of the island hooks toward the west when the sea has been easterly for a continued period and toward the east when the sea is westerly.
There is a small patch of wild rye (Elymus mollis trin) and a narrow fringe of a low creeping vine along the easterly shore of the pond. Another very small patch of wild rye is on the plateau. There, are numerous small tufts of grass and a very short green moss on the plateau and the eastern slope of Castle Rock. The sea gulls spread the wild rye and other seed in making their nests and in a few seasons the plateau will be covered with grass and moss unless there is another volcanic eruption. At present the vegetation is too sparse to change the grayish black hue of the island as seen from the sea.
There was no fresh water on the island so drinking water was brought ashore in kegs. The washing was done in sea Water.
The island is used as a breeding ground by sea lions. There were hundreds of sea oils along the sand beaches of the island on June 1. At that date most of the sea lion calves had been born although there were a few born as late as June 16. A rough estimate would apportion the cows and bulls at about 20 cows to each bull. At this time of the season the bulls jealously guarded the cows, always staying between the cows and the intruders. Both bulls and cows would abandon the calves and get out of possible danger. The calves would make small effort to escape, but would bawl loudly when handled by anyone. When the calves were about 2 months old key became more wary although at 3 Months they could be approached when asleep. About the second week in July the bulls and cows began leaving until near the first of August there was only one cow for every 6 or 8 calves and about 50 bulls on the island. Each cow would herd about 6 or 8 calves, keeping them in the Water a good deal of the time evidently etching them the fine points of swimming and fishing. The roar and barking of the entire herd made a continual sound like an airplane a short distance overhead.
The herd was quiet for only a few of the very early hours of the morning. When the camp was first established the sea lions were very timid and wouldn’t allow one to get close to them, but as they became more accustomed to us they became more inherent; in fact, the rodman had trouble getting them to move so he could rod in the high water line without walking among them. I found it difficult to approach close enough to get close-up snapshots with a camera.
About 1,000 sea gulls (glaucous gull) were nesting on the plateau. The nests consist of slight hollows in the sand lined with a wisp of grass or a short piece of kelp. The gulls lay two or three eggs in a nest about June 1. They did not replace any eggs taken after the third week in June. One of the party placed a dozen eggs in one nest and the gulls had distributed the eggs so there were no more than three in any nest by the following morning. The eggs hatched the latter part of July. After the young had hatched, the gulls would try to rout intruders by swooping at them in a “power dive” and by setting up a great racket. Occasionally a gull would drop a murre egg near the intruder but this was more likely by accident than by intent.
The pallas murres arrived between the first and fifteenth of June. There were 50,000 of them by a conservative estimate nesting on the pinnacle rocks and Fire Island. They laid a single egg pushed against the side of the cliff.
The sea gulls preyed on the murres, stealing the eggs when the murres left them. The gull would sometimes break open the egg and eat it, but usually would carry it away in its beak or throat. When the young gulls were hatched the old ones swarmed around the murres to steal eggs. I’ve often seen a gull tug at the tail feathers of a murre to get it to move while a second gull would take the egg. The gulls would carry eggs in their beaks for a quarter of a mile to their nests. Early in August when the murres began to hatch, the gulls would steal the young murres and swallow them head first at a gulp or carry them away to feed to the young gulls. The murres would try to fight off the gulls from the young, but the gulls would hover around until their opportunity came to steal either an egg or a murre. The murres stopped laying eggs near the middle of August. The gulls would try to take the murres from one another while in flight and several murres would change captors in mid-air. A few fell to the ground and escaped for the moment. When the young murres grew so large that the gulls could no longer swallow them, the gulls would carry them away and decapitate them and eat all but the feathers and the breastbone. A few gulls that were killed were eaten by other gulls.
A few cormorant nested in inaccessible places on Castle Rock and Fire Island. A few sea parrots (tufted puffins) nested in the crevices of the volcano, hiding their eggs from the thieving gulls. Toward the end of August a large flock of sabine gulls came to the island and fished in the surrounding water. Nearly all of the birds had left the island by September 15. Swarms of furry covered flies infested the loose rocks around the pinnacle rocks. These were very sluggish even on warm days.
The murres were pestered by a tick about the size and appearance of a small wood tick. These became especially numerous the second week in August. As many as 100 were picked off the inner walls of the tent each day for a week. Several got on the members of the party but only one tick drew blood.
Bogoslof Island has a local reputation for shifting position rather frequently. This can be accounted for by two reasons other than faulty navigation. Although the island is small it presents a marked difference in appearance when viewed from different directions. Anyone glimpsing the island from different directions on widely separated occasions might believe the island to have changed. The charted positions of the shore lines of Unalaska and Umnak Islands in the vicinity of Bogoslof are in error by a few miles. A navigator taking his departure from different points on Unalaska or Umnak Island would obtain different dead reckoning position of Bogoslof Island which would create the impression that Bogoslof had shifted in position.
The position of Bogoslof may change the next time the volcano erupts, but that can be proved only after the next eruption. Until then it is doubtful if there will be any major change in the configuration of Bogoslof Island.