All fuzz and fat, the nestling is at this point quite defenseless and, to some both past and present, most delectable. Additionally, the strong fishy odor of the bird and its food is a sure lure. Wily predators drag eggs and chicks from burrows, ambush birds at tunnel entrances, and leave behind telltale signs of deadly deeds. Dogs mutilate carcasses, scattering feathers and limbs over a wide area. Rats leave eggshell pieces unevenly chewed, and eat and drink the contents.
Mongooses chew a small hole in the side of the egg and lick up the insides.
In 1995, a cat trapped in a petrel nesting area had petrel feathers in its gut. The condition of the remains fingered cats as the likely culprits. Although it is not known how long cats have roamed the subalpine, it is certain that continued predation will result in the petrel's extirpation. Its population has now dwindled and contracted to a relatively small number of birds that find their primary refuge within protected national park lands. Pet owners are a part of the solution when they neuter all cats that are let outdoors and take unwanted house pets to Humane Society shelters, rather than abandon them in the wild.