58 “TERRA NOVA” EXPEDITION. 
In every case where I was able to distinguish between the cock and the hen, 
the latter remained on or by the nest, and built it with the stones which the cock 
brought her, and I think the work is always divided between them in this way. 
After watching very carefully for some days, I came to the conclusion that 
pairing never takes place before the birds arrive at the rookery. All those in the 
long line that approached the breeding ground seemed quite independent of one 
another. 
During the march across the sea-ice on their way to the rookery, they use 
both the methods by which a penguin travels over solid ground; viz. : by walking 
and tobogganing (PI. II). It was most interesting to walk some way out along the 
approaching line, and then to stand and watch it stream past. 
First would come a string of birds toddling along, their little legs enabling 
them to advance only about six inches at each step; but, goimg at the rate of about 
130 steps per minute, they covered some two-thirds of a statute mile per hour. In 
the still aw their little wheezy respiration could be heard distinctly, and they 
seemed to be somewhat out of breath. 
Close on their heels would come another string, tobogganing on their breasts, 
and using their legs as propellers, the rate of progression being exactly the same as 
when they walked, so that the procession kept its formation as it passed over the 
ice. Every now and then those that walked would flop forward on to their breasts 
and toboggan, and those that tobogganed would as suddenly pop up on to their legs 
and walk. 
On October 19th nest-building was in full swing, with all the squabbling and 
thieving that has so often been described by different writers. 
Some of the birds seemed inveterate thieves, and collected most, if not all, of 
their stones in this way. Depredators, when caught, were driven off with great fury 
by those whom they attempted to rob, and were sometimes chased for some distance. 
It was curious to see the difference in the appearance of the fleeing thief and his 
pursuer. As the former raced away among the nests, doubling on his tracks, and 
attempting by every artifice to get lost in the crowd, and so rid himself of his pursuer, 
his feathers lay close back on his skin, giving him a sleek aspect which made him 
appear half the size of the irate bird who sought to catch him, with feathers ruffled in 
indignation. 
To the human eye there is not the slightest difference in the outward appearance 
of the cock and the hen. Even when a particular pair have been watched for many 
days, so that they are quite familiar to the observer, not the least distinction can 
be seen, though after some experience differences in their behaviour may be noted 
at once, whilst the muddy marks of the cock’s feet on the hen’s back, when these 
are present, serve to distinguish one from the other at a glance. 
Without cessation the stream of arrivals continued until October 30th, when it 
became intermittent, and two days later had stopped altogether. By this time the 
