soulless, shelled crab-people are not given to scratch much—­at least, not in that way.  They were rats—­shore rats.  The last designation is necessary, for there are rats and rats, all bad, but the shore rat is the worst.  How many sleeping birds, wounded, tired, or unalert, die at his hands, or, rather, his teeth, in the course of a year would amaze anybody if known, and the shell-fish he relieves of life are legion.

The hard, horny carapace of a retreating crab scraped, in the dead silence, against the rock-bowlder on which the skua sat.  He made no move at the sound, the suggestive sound; but his feathers were shut down quite tight, and he looked far smaller than usual.  When birds shut down their feathers in that fashion they put on an armor coat, as it were, through which very little can pierce.  It showed that he was ready.

And you think that the mere shore crabs could be nothing to him.  But a few hundred ravening shore crabs, with their lives for sale—­all digging pieces out of you in the dark—­are not so easy a proposition to dispose of as people may think.  Try it.

One of the rats turned suddenly and faced towards him.  The skua could see its little, cruel eyes gleaming like gimlet-holes in the wall of a lighted room.  Then another, and another, and another did the same.

The skua was scarcely bleeding at all now, but he had left enough of a trail for them—­they who make a specialty of the job.  And they followed it.  Hopping grotesquely across the mottled, hurrying patches of moonlight they came, one behind the other, and without noise.

The skua remained as still as the bowlder he sat upon.  In that position, even peering closely, you would never have seen him, unless, like ourselves, you knew he was there.  But he was drawn together, drawn in all his muscles like a tense spring, and—­though this his persecutors could not know—­he was recovering from his hurts rapidly, with the wonderful power of recuperation of all the wild-folk, who pay their price for it in clean, hard living.

Then suddenly there was a scuffle below him in the dark.  One of the rats squeaked a little, acknowledging receipt of a crab’s pincers closed upon him, or her.  Followed the sounds of some scuttering, confusion, and the horrible slide and scrape of horny shells upon stone.  Then silence, and the skua knew that, in that wonderful way they have, the crabs, at any rate, were gone—­for the moment.

Remained, however, the rats, and one peered up over the bowlder the next instant, its eyes glinting in a momentary splash of moonlight fiendishly.  Also, his quick ears could hear the soft creepings of the others on every side of the bowlder, back and front.  They had surrounded him, and, like wolves, would now rush, and then—­and then——­ They had gone.

Yes, there could be no shadow of doubt about it.  There had come an instant’s furtive, hurried movement, a glimpse—­no, half a glimpse—­of hunched forms hopping through the dark, and they were no more.