Ninja penguins. Y'know, it was just a matter of time... I mean, this is a comic book. And anybody who reads comic books knows you can't spit in these things without hitting a ninja.
They belong to Archibald Jax, a ronin clown, the bad guy. It's a small cadre of Rockhoppers. You can tell by the plumage (though the second from the right looks more like a viking magpie than a rockhopper ninja).

Wrong place, wrong time, birdbrains. I've got three words for the lot of you...
Come get some...