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. On October 21 many thousands of penguins arrived from the northerly direction, and poured on to the beach in a continuous stream, the snaky line of arrivals extending unbroken across the sea-ice as far as the eye could see. [Illustration: Fig. 16. PART OF THE LINE OF APPROACHING BIRDS, SEVERAL MILES IN LENGTH (Page 28)] A great many now started to climb the heights up the precipitous side of Cape Adare and to build their nests as far as the summit, a height of some 1000 feet, although there was still room for many thousand more down below. What could be their object, considering the wearisome journeys they would have to make to feed their young, it is impossible to say. It might be the result of the same spirit which made them spread out in little scattered groups over the rookery when only a few had arrived, and that they prefer wider room, only putting up with the greater crowding which ensues later as a necessary evil. There is, however, another explanation which I will discuss in another place. At 9 P.M. it was getting dusk, and the rookery comparatively silent, although on some of the knolls two or three birds might be seen still busily working, toddling to and fro fetching stones. The other thousands lay at rest, their white breasts flat on the ground, and only their black beaks and heads visible as they lay with their chins stretched forward on the ground, whilst in place of the massed discord of clamour heard during the day, the separate voices of some of the busy ones were distinct. A fine powdering of snow was falling. It would be difficult to estimate the number of penguins that poured into the rookery during the following day. There was no evidence that any pairing had taken place on or before the march, and the birds all had the appearance of being quite independent.