Finder's Keeper?

So here’s the deal. This sweet green Fuji bike has been chained outside my sister’s apartment for like 2 years. Hasn’t moved—it’s deteriorating pretty bad, but it is such a cool bike. It has been chained to a street sign for at least two years.

How do I claim it? I’m guessing its owner moved or something and didnt feel like dealing with selling it/whatever—there are a million possible explanations, but the bottom line is that the bike is just sitting. This is NYC, so it’s kindof impressive it hasn’t been stolen! haha

Is there any way I can stake claim to it? Honestly, I came here first because I’m lazy—should I be looking up NY laws? Just looking for a quick answer—if need be, I’ll do the research. THanks!