[Illustration:  THE EMPERORS ROOKERY]

“The change here was immense.  Ross Sea was open water for nearly thirty miles; a long line of white pack ice was just visible on the horizon from where we stood, some 800 to 900 feet above the sea.  Large sheets of ice were still going out and drifting to the north, and the migration of the Emperors was in full swing.  There were again two companies waiting on the ice at the actual water’s edge, with some hundred more tailing out in single file to join them.  The birds were waiting far out at the edge of the open water, as far as it was possible for them to walk, on a projecting piece of ice, the very next piece that would break away and drift to the north.  The line of tracks in the snow along which the birds had gone the day before was now cut off short at the edge of the open water, showing that they had gone, and under the ice-cliffs there was an appreciable diminution in the number of Emperors left, hardly more than half remaining of all that we had seen there six days before."[19]

Two days later the emigration was still in full swing, but only the unemployed seemed to have gone as yet.  Those who were nursing chicks were still huddled under the ice-cliffs, sheltered as much as possible from the storm.  Three days later (October 28) no ice was to be seen in the Ross Sea:  the little bay of ice was gradually being eaten away:  the same exodus was in progress and only a remnant of penguins was still left.

Of the conditions under which the Emperor lays her eggs, the darkness and cold and blighting winds, of the excessive mothering instinct implanted in the heart of every bird, male and female, of the mortality and gallant struggles against almost inconceivable odds, and the final survival of some 26 per cent of the eggs, I hope to tell in the account of our Winter Journey, the object of which was to throw light upon the development of the embryo of this remarkable bird, and through it upon the history of their ancestors.  As Wilson wrote: 

“The possibility that we have in the Emperor penguin the nearest approach to a primitive form not only of a penguin but of a bird makes the future working out of its embryology a matter of the greatest possible importance.  It was a great disappointment to us that although we discovered their breeding-ground, and although we were able to bring home a number of deserted eggs and chicks, we were not able to procure a series of early embryos by which alone the points of particular interest can be worked out.  To have done this in a proper manner from the spot at which the Discovery wintered in McMurdo Sound would have involved us in endless difficulties, for it would have entailed the risks of sledge travelling in mid-winter with an almost total absence of light.  It would at any time require that a party of three at least, with full camp equipment, should traverse about a hundred miles of the Barrier surface in the dark and