Sharp-toothed Aliens Attack!!!!!

Camp Connell, Ca. - I am not making this up.
Something strange is eating my steps. There are teeth marks on what is left of the risers on the stairs, and I have been hearing strange gnawing sounds off and on recently.
Here's what it looks like at the entrance:

And then I started noticing that within a very short time after I put out feed for the birds in the neighborhood, it began to disapear. Like this:

And then I spotted this:

Using my keen investigative skills I figured out that aliens have penetrated the bodies of the normally benign squirrels in my area, and they are mounting a concentrated attack.
We have squirrels: grey squirrels, which are the biggest and lope around like foxes all around the house; ground squirrels, seen in the picture, which are the most voracious and can fill their cheek pouches with an endless stream of food types; Douglas squirrels, also known as Chickarees, which can eat 3,000 cones a year and often do; and assorted chipmunks, including the long-eared variety who clean up after their bigger cousins.
And we almost certainly have flying squirrels, though I have never seen one here. They only descend from the tree-tops at night, munching whatever they find including fungi, and then disappearing back into the heights before dawn. As a kid, my friends and I tried to tame them only to learn the basic Squirrel 101 lesson: squirrels bite.
Seen from one perspective they are cute little buggers, endlessly entertaining with their antics and scolding and squeaking.
But I think they are possessed by the devil, determined to eat my porch and drive the birds away.
The only thing worse are the feral cats that come around to hunt them, spawn of evil.
And then, I spotted these new guys, shortly after hearing my bird feeder rattle empty. to the ground.

If I don't re-appear in the next few days, call the secret Air Force UFO experts and tell them what happened.