I am somewhat of an expert on boys. I am bristling with (and sometimes at) brothers, swarming with sons and I have grandsons galore. I have worked for many years with cub scouts and boy scouts, I have a father, husband and son-in-law. I am surrounded by boys.
This truth I hold self evident: Boys make noise. That's not the same as saying that they are noisy. My boys aren't particularly noisy. They are just capable of making a lot of noise.
Girls aren't always quiet, but if they are making noise it's usually talking, sometime shrieking, and if you're really unlucky an awful lot of giggling. Boys will bang on things, make sound effects for toys cars, drop things just to see what happens, kick things just because they can - and then when you ask them to stop they'll look at you with innocence fairly dripping from their faces and say "what noise?"