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Okay, so I've been writing this story about this guy named Alex who was created in a labratory (he has feline genes) and subjected to lots of horrible and abusive tests. He escaped when he was ten, thanks to a scientist named Marion. He and four other mutants: a avian boy named James, another feline girl named Tawni, and two shark kids named Eve and Daemon. They lived in an abandoned eagle's nest for six years, until Hunters (who do the lab's dirty work) found them and kidnapped Daemon. The other four followed them to L.A, where they met some members of the Ravencloud Organization (from a different story, maybe I'll post that later). Then, they were all captured by Hunters and taken back to the lab. There, they met Shane and Hehena, another avian-human and a genetically enhanced assassin. Alex was assigned to a scientist named Maeve and subjected to more testing. After two days, he and James were sent to the reject room to be killed. There, they discovered that Shane died during testing, and met a young girl named Cerulean, who is her butterfly larvae stage. Two of the Ravencloud Organization came and rescued them, and they are escaping on a dragon.

That's as far as I've written so far, and I suddenly realized that it sounded a lot like James Patterson's Maximum Ride...help! Is it?

i know I probably spelled plageurism wrong, but I didn't want to look it up...and what other stories?

Lilo and Stitch - an alien is created, he escapes, hides out for a while until he is hunted down and captured.
X-men 3 - a bunch of genetically altered people that are hunted down to be exterminated.
You can make a lot of comparisons if you think abstractly enough about anything smile

Personally I haven't read Maximum Ride (though I've heard it is amazing and that I should invest some time in it.)
I personally believe that your story would only be plagiarism if you follow Maximum Ride's plot line more then 75% of the time and the characters are all very similar. (and also if you were going to try and publish your story instead of just write it for the fun of it.)

You could maybe diverge from your plot by giving it some unexpected twist that makes it stray from Maximum Ride. You could alter your character's personalities to be different from Maximum Ride's characters. There are a lot of tiny things that you can do that add up to make a big difference.