Non-native bird invaders
Some birds imported from other continents escaped or were intentionally released. In fact, even birds from a different part of our continent can become problematic for our own native birds. For example, these house finches, native to the US West, spread through the Northeast after being released in Long Island about 50 years ago.
Pigeons are another non-native bird, but we seldom see them in our yard, even though we frequently see them just a few blocks from our home. The main invaders in our yard are house sparrows and starlings.
European house sparrows are the worst animal invaders in my yard, especially because they're here year-round. Large flocks of these birds eat huge amounts of food, and they aggressively crowd out other birds. Even worse, they compete for nesting spaces and are usually the victors.
Interestingly, they do have one parasite: cowbirds.
One interesting fact is that they actually aren't sparrows at all—they're weaver finches.
Song sparrow — a true, native sparrow that is a delight to have around
True sparrows, even though they tend to also be what are called "LBJs" (little brown jobs), are quite charming and often very beautiful once you learn to distinguish one from the other.
Some of our favorites are white-throated sparrows, white-crowned sparrows, song sparrows, and chipping sparrows, among others.
Even towhees and juncos are in the sparrow family. At first I was surprised to learn this since they're not a variation of brown markings, but they scratch for bugs in the same way as other more sparrow-looking sparrows.
Starling taking over house sparrow nest
This is what I call poetic justice!
After harassing and displacing so many other native birds, this house sparrow is helpless to combat this European starling when he tried to take over the house sparrow's nestbox.
These starlings sometimes arrive in large flocks, but fortunately we generally don't have so many at once, though even one is more than enough.
They compete for nesting areas with our native birds, and generally are unpleasant to have around.
This starling is eating the winterberries that our robins and Northern mockingbird rely on to help them get through the long winter.
Starlings are pretty aggressive and chase away other birds. Even worse, they tend to travel in large flocks and can strip the bushes bare, leaving little for our native birds.