Well, it depends on who you ask....
As you will find out, if you ask ten pigeon people the same question, you are going to get ten answers. And they will ALL be different.
But, I would say they are... But if I was questioned by the city, no, they aren't fowl... 
 
But, typically when a list of fowl is reviewed, pigeons do not exist on the list.
But, then fowl can also mean all birds, from hummingbirds to penguins.
So, I typically say they are, until it means fighting city codes. I know, I'm a hypocrite!