The surface of the snow on the sea-ice varied continually, and over any very smooth patches the pedestrians almost invariably started to toboggan, whilst over “bad going” they all had perforce to walk.
Figs. [16], [17], [18] and [19] present some idea of the procession of these thousands on thousands of penguins as day after day they passed into the rookery.
Fig. 15. ON THE MARCH TO THE ROOKERY OVER THE SEA-ICE. SOME ARE WALKING AND SOME “TOBOGGANING”
When tobogganing, turning to one side or the other is done with one or more strokes of the opposite flipper. When fleeing or chasing, both flippers as well as both feet are used in propulsion, and over most surfaces tobogganing is thus their fastest mode of progression, but when going at full tilt it is also the most exhausting, and after a short spurt in this way they invariably return to the walking position.
By October 20 many of the nests were complete, and the hens sat in them, though no eggs were to be seen yet. In the middle of one of the frozen lakes rose a little island, well suited for nesting except for the fact that later in the season, probably about the time when the young chicks were hatched, the lake would be thawed and the approach to the island only to be accomplished through about six inches or more of dirty water and ooze. Until then, however, the surface of the lake would remain frozen, and was at this time covered with snow.
Not a penguin attempted to build its nest on this island, though many passed it or walked over it in crossing the lake. How did they realize that later on they would get dirty every time they journeyed to or from the spot?
Not far from this island another mound rose from the lake, but this was connected with the “mainland” by a narrow neck of guano-covered pebbles. This mound was covered with nests, showing that the birds understood this place could always be reached over dry land. Surely this was well worth remarking.
There was a part of the ice-foot on the south side of the rookery where a track worn by many ascending penguins could be seen, leading from the sea-ice on to the beach. The place was steep and the ice slippery, and, in fact, the track led straight up a most difficult ascent. Not ten yards from this well-worn track a perfectly easy slope led up from the sea-ice to the rookery. The tracks in the freshly fallen snow showed that only one penguin had gone up this way. Presumably the first arrival in that place had taken the difficult path, and all subsequent arrivals blindly followed in his tracks, whilst only one had had the good luck or independence to choose the easier way.