Nests of dried weeds littered the ground, and eggs and young were everywhere. The little ones were covered with white down, and the developing feathers on their wings were turning black. They squalled unremittingly, which squalling I decided was not so much on my account as because of a swarm of black flies that attacked them when the mothers flew away. I was hard put to it myself to keep these flies, large as pennies and as flat, from eating me alive. They slipped up my sleeves and trousers and their bite made a wasp-sting pleasure by comparison.
By rushing into a flock of _rabihorcados_ I succeeded several times in catching one in my hands. And spreading it out, I made guesses as to width from tip to tip of wings. None were under seven feet; one measured all of eight. They made no strenuous resistance and regarded me with cold eyes. Every flock that I put to flight left several dozen little ones squalling in the nests; and at one place an old booby waddled to the nests and began to maltreat the young _rabihorcados_. Instincts of humanity bade me scare the old brute away until I happened to remember the relation existing between the two species. Then I watched. With my own eyes I saw that grizzled booby pick and bite and wring those poor little birds with a grim and deadly deliberation. When the mothers, soon returning, fluttered down, they did not attack the booby, but protected their little ones by covering them with body and wings. Conviction came upon me that it was instinctive for the booby to kill the parasitical _rabihorcado_; and likewise instinctive for the _rabihorcado_ to preserve the life of the booby.
A shout from Manuel directed me toward the extreme eastern end of the island. On the way I discovered many little dead birds, and the farther I went the more I found. Among the low bushes were also many old _rabihorcados_, dead and dry. Some were twisted among the network of branches, and several were hanging in limp, grotesque, horribly suggestive attitudes of death. Manuel had all of the Indian's leaning toward the mystical, and he believed the _rabihorcados_ had destroyed themselves. Starved they may very well have been, but to me the gales of that wind-swept, ocean desert accounted for the hanging _rabihorcados_. Still, when face to face with the island, with its strife, and its illustration of the survival of the fittest, all that Manuel had claimed and more, I had to acknowledge the disquieting force of the thing and its stunning blow to an imagined knowledge of life and its secrets.