To realize what this meant, we must remember that an Adélie penguin's eyes being only about twelve inches above the ground when on the march, his horizon is only one mile distant. Thus from Cape Adare he could just see the top of the mountain on Duke of York Island peeping above the horizon on the clearest day. In anything like thick weather he could not see it at all, and probably he had never been there. So in the first place, what was it that impelled him to go on this long journey to meet his friends, and when so impelled, what instinct pointed out the way? This of course merely brings us to the old question of migratory instinct, but in the case of the penguin, its horizon is so very short that it is quite evident he possesses a special sense of direction, in addition to the special sense which urged him to go and meet the Duke of York Island contingent, and I may here remark that when we were returning to New Zealand in the summer of 1913, we passed troops of penguins swimming in the open sea far out of sight of land,—an unanswerable reply to those naturalists who still maintain that migrating birds must rely upon their eyes for guidance, and this remark applies equally to the penguins we found on the northern limits of the pack-ice, some five hundred miles from the rookeries to which they would repair the following year.
| Mean date | Northern limit of pack | Miles from C. Adare | Southern limit of pack | Miles of pack N. and S. | Remarks |
|---|---|---|---|---|---|
| Feb. 3, 1839 | 68° S. | 190 | ? | ? | Balleny |
| Jan. 1, 1841 | 66° 30′ | 280 | 69° | 150 | Ross |
| Feb. 1, 1895 | 66° 15′ | 300 | 69° 45′ | 210 | Kristensen |
| Feb. 8, 1899 | 66° 0′ | 315 | 69° 0′ | 180 | Borchgravink |
| Feb. 27, 1904 | ? | 70° 30′ | ? | Scott | |
| Feb. 15, 1910 | nil | nil | Terra Nova | ||
| Mar. 13, 1912 | nil | nil | Terra Nova | ||
| Jan. 30, 1913 | nil | nil | Terra Nova |
Note.—Ross, Kristensen, Scott, Shackleton and Pennell all, however, found pack late in the season while trying to work west along the coast when only some forty-five to seventy-five miles north of Cape Adare, and all were turned by this pack.
According to Pennell, it appears probable that there is a great hang of pack in the sea west of Cape Adare and south of the Balleny Islands, and most likely it is here that the Adélies repair when they leave Cape Adare rookery in the autumn. I think, however, it is safe to assume that they seek the northernmost limits of the pack during the winter, as these would offer the most favourable conditions.
| Date | Longitude | Northern limit | Extends N. and S. Miles | Minutes of latitude Northern limit is N. of Cape Adare |
|---|---|---|---|---|
| Jan. 12, 1840 | 166° E. | 64° 30′ | — | 400 (Wilkes) |
| Jan. 3, 1902 | 178° E. | 67° S. | 140 | 250 (Discovery) |
| Dec. 31, 1902 | 180° E. | 66° 30′ | 60 | 280 (Morning) |
| Second belt | 69° | 30 | 130 (Morning) | |
| Dec. 20, 1908 | 178° W. | 66° 30′ | 60 | 270 (Nimrod) |
| Dec. 9, 1910 | 178° W. | 64° 45′ | 300 | 390 (Terra Nova) |
| Dec. 27, 1911 | 177° W. | 65° 20′ | 160 | 360 (Terra Nova) |
| Mar. 8, 1911 | 162° E. | 64° 30′ | 270 | 400 (Terra Nova) |
Fig. 8. “… And later, form the Beautiful Terraces of the Ice-foot”
Fig. 9. Penguins at the Rookery