Native, but invaders nonetheless
Deer are part of the ecosystem in natural areas
I don't have anything against any individual animal. The problem comes when it's in the wrong place—even if they're native to this area.
Part of the problem, I believe, is our pattern of growth. Where do we expect wildlife to go? We've taken all the land.
Some of the native invaders we have in our yard are:
Slugs and snails
Both native and introduced slugs are in the Northeast (and in other areas of the country). I've read that the native species are beneficial, which makes sense since ecosystems have evolved over millions of years to function efficiently.
I don't know which of our slugs and snails are native and which are introduced species, but I do know that they can be very destructive at least in a home landscape setting.
Slug or snail eggs
Toads will eat them, and although I suspect we have a good number of toads per square foot, in some years slugs become quite a problem. We try to make our yard as hospitable to toads as possible!
When we have a severe problem (I believe this tends to be the wetter summers), we devote some time to hunting down the egg masses.
Here, we've found them under the bark of our log edging.
Squirrels are in a "gray" area, so to speak. We don't mind a few, but usually there's more than a few, and they can often eat a lot more than we'd like. Squirrels are native, but more plentiful in a human urban environment than they would be in a more natural setting.
It's annoying when they eat the food I put out for birds, but this doesn't happen often since the baffle usually thwarts them.
The problem usually occurs when I have some longer feeders such as finch socks that hang below the level of the baffle. They grab onto those to get over the baffle, or sometimes the baffle slips down too far. All in all, though, not a serious problem in the bigger scheme of things.
Generally, when we see how much ingenuity and persistance they've shown to achieve their goal, we decide they're entitled to an occasional treat. It's just a money issue, since buying bird seed is expensive.
Seeing squirrels eating berries I planted for the birds, such as this pagoda dogwood (Cornus alternifolia), is more distressing.
We intend that these native berries to be nutritious food for the birds. One squirrel can eat more berries than many birds would eat, and the berries are in limited supply.
We don't mind if the squirrels eat the apples because our apples aren't very good. When we first planted the tree about 30 years ago, we didn't think much about pesticides.
Except for the first few years, we have never sprayed the tree, and you just can't have good apples without spraying I guess.
(There are some specific varieties that lend themselves to organic production, but not this one …)
We do mind that squirrels eat all of our pears, though, since the pears are good even without being sprayed. But we've given up. At least when they eat pears, they aren't eating our other garden produce, such as our tomatoes.
It's frustrating when they don't finish the fruit. The remains of their chewings are at the top left; the core, poised to drop on someone's head, is on the right.
One thing that distracts squirrels from raiding the bird feeders is throwing corn kernels under the arborvitae.
It gives them something to eat that isn't as expensive as the sunflower seeds I have in the feeder.