In few forms of life are the factors of survival so perfected. Observers in Tasmania, Australia and New Zealand have watched flocks of the "Muttonbird" surpassing in numbers former congregations of our Passenger Pigeon. Flinders saw one such assemblage that he thinks numbered about 150,000,000 birds! It seems incredible that a species laying only one egg a year can increase to such multitudes.

The egg is laid in burrow, the parents all leave the nesting area before dawn because they are helpless on land. Gulls and other enemies are frustrated, and their life tenacity is extraordinary. Before leaving the home entrance is covered with grass and mortality among young is nil. Longevity must be another important factor. The half million young salted down by half castes in Tasmania seem to have no effect on the number.

The birds come to their island apartments in absolute silence. About 7:30 P. M. when the majority have arrived there is a sudden outburst of gurglings, groans and hoarse laughter — like lost spirits celebrating return to earth! Na-kwa-kwa is the Maori name, representing the call notes.