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APPENDICES.
birth to their young in autumn or winter months mostly far from Norway in the western parts of the North Atlantic "; if Collett had said "winter or early spring instead of autumn or winter," the agreement would be complete. It is possible that the genial conditions of climate which the majority of the blue whales, as well as humpbacks and probably finners, appear to seek for parturition may supply a stimulus necessary to excite sexual activity in the majority of the males and unimpregnated females; and the coincidence of parturition and pairing which apparently exists may be merely the result of a period of gestation of twelve months. As might be expected, having regard to its length, the observations on the ovaries of Nos. 43 and 198, made by Major Barrett-Hamilton, afford evidence of the polycestrous character of the sexual season. In the first case only one ovary was functional (cf., the discussion of the twin foetuses of the finners at p. 123 above); this ovary had six corpora lutea, one of which was large, swollen, and pro- vided with a distinct scar, a circumstance which, together with the congestion of the corresponding uterine cornu and the size of the uterus, led Major Barrett- Hamilton to think that No. 43 had been recently impregnated for the first time, although he did not find the fœtus; the five smaller corpora lutea furnish satis- factory evidence of as many periods of "heat" prior to the astrus which was apparently satisfied. No. 198 had three corpora lutea of moderate size, two in one ovary and one in the other; in this whale clearly both ovaries were functional, although it is doubtful whether impregnation had happened or not.
In each of the three cases of twinning recorded from the Finmark coast the twin fœtuses were of equal length and, therefore, in all probability, the products of a single pairing. In the instance from the Faroes recorded by Mr. Harvie- Brown, the difference in the length of the foetuses, assuming that the Faroe whale was really a blue whale and not a finner as I believe, indicates that a second pairing took place about twenty-four days later than the first pairing and resulted in the conception of the smaller fœtus.
No nursing females were seen by Major Barrett-Hamilton at South Georgia: from the report on whales captured off South Georgia, made to the British Museum by the Southern Whaling Company, it appears that that company killed a female 92 ft. long and her male calf 35 ft. long on 17th December, 1913.
The rate of propagation is probably the same as in the finners, viz., the female normally does not give birth to a calf oftener than in alternate years, the calf being weaned, in all probability, either before or immediately after the renewed impregnation of its dam.
MIGRATION.
The best account of the migration and habits of the blue whale appears to be that of Professor Collett (Norges Pattedyr, p. 586), and, as in the case of the finner, I have drawn my facts for this section of my report largely from this source. Plankton, of one sort or another, is the essential food of the blue whale, and I am not aware of anything else having been found in its stomach hitherto.
This whale spends a large portion of each year in migration. In the North Atlantic it moves, in the early spring, from the temperate, or it may be the sub- tropical, waters of the North American coast and, passing in a north-easterly direc- tion, along a course which appears to be largely in the Gulf Stream, it enters the Arctic Ocean, where it passes the suminer. The return migration takes place towards autumn.
As a proof that the migration extends from the New to the Old World one may quote the fact that on several occasions harpoons of American origin have been found in the bodies of blue whales caught at Iceland and Finmark; in the summer of 1886 one killed at Iceland was found to be carrying a harpoon which it had received while visiting the Finmark coast during the previous year.
As early as February the blue whale is seen migrating eastwards, off the coast of Newfoundland; in April (and sometimes in March) it is found at Iceland moving eastwards or north-eastwards; the most easterly of the migrating schools pass close to the west coast of Ireland and the Hebrides in May or June.
In the summer the species is (or was) found in the North Sea and the Arctic Ocean off the coasts of Greenland, Iceland, Spitzbergen, Bear Island, Finmark, and thence along the whole Murman coast to Novaja Zemlja and the White Sea.
APPENDICES.
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In the autumn, in August, or the beginning of September, the schools migrate from the eastern Arctic Ocean towards the west and south. The course which they follow traverses the open sea without touching the west coast of Norway or the North Sea, but it strikes along the western coasts of the Hebrides and Ireland though rarely touching the Faroes and Shetland. According to Mr. Haldane the course of the migration (probably both in the spring and in the autumn) follows approximately the meridian of 100 W. longitude, passing between Iceland and the Faroes and spreading out northwards of Iceland in an east and west direction; migrating blue whales are fairly abundant in the season to the west of St. Kilda, but they are decidedly rare in Shetland waters (see table at p. 148 below). At Iceland a good catch is often made as late as in August, but by September blue whales are rare there. In North British waters, according to Mr. Haldane, they are most abundant in July and August.
In October and November migrating schools appear off the coast of Newfound- land, where, however, scattered individuals may be found throughout the summer. Professor Collett says that it is probable that this species passes the winter in the open basin between the eastern United States of America and the Azores; since we have reason to believe (as discussed above) that the pairing and parturi- tion of the great majority of the blue whales take place in the winter and early spring, we may assume this region to be the chief scene of those events.
Collett describes the blue whale as being less gregarious than the finner; the individuals are relatively scattered and their progress somewhat slow. When arriving in great force a pair or a few individuals may be seen travelling in close company.
"They often come inshore, but not during on-shore wind; during storms they always seek the open sea. Although they often travel against the wind they prefer to keep in the lee (on the Finmark coast); if the pre- dominating wind in the summer is E. or N.E., a good catch has often been made west of the North Cape, while under continuous southerly or south- westerly winds these whales have stayed farther towards the east.
If the weather be calm and plankton sufficiently abundant they can remain in one neighbourhood for a long time, until driven away by a
storm.
Each school is wont to consist of individuals of similar age; in May, 1875, a company of large and full-grown whales stayed for fourteen days in the mouth of the Varangerfjord, whence they were driven by a breeze which lasted for several days; later the same ground was occupied by another school, which consisted entirely of smaller individuals" (Collett). Collett says that on the Finmark coast the blue whale was, in the sixties (when systematic whaling first began), an annual and numerous visitor, and Svend Foyn's first captures consisted entirely of this species, which at that time could be found far in the Varangerfjord.
"Since the eighties its visits have been less regular; the whales are no longer in the habit of showing themselves so far towards the east as formerly, and they have often stayed so far from land that it has been difficult to find them, or else they have apparently been quite absent.
"The blue whale seldom appears off the coast before the end of May or the beginning of June. In 1887 an individual was caught outside Sylte- fjord as early as 10th May, and it is stated that in the seventies, in the first period of whaling, the species as a rule arrived in the Varangerfjord about the 8th May. At this time marine Crustacea first became sufficiently plentiful here in order to afford food for this species.
"This migration always comes from the west or south-west; several times in the nineties harpoons of American origin (probably from New found- land) have been found in the bodies of blue whales killed off Finmark.
In addition new invasions can happen throughout the summer, but as a rule the chase is over by the end of July; sometimes schools can be seen in August, and individuals are met with exceptionally in the first half of September.
"In Norwegian waters it is found almost only off Finmark. On the Tromsö coast it shows itself already more rarely; and from Lofoten and southwards the blue whale seldom comes inshore voluntarily."