Whistling Ghost

So I'm sat downstairs in my house, just about to go up to bed. Everyone else is upstairs and I hear this very distinctive tune coming from the kitchen. I was naturally freaked out by this at first but me, wanting to just rationalise everything, I merely said it was the wind or my brother whistling upstairs even though that would hardly make sense as I was sure I had heard it coming from the kitchen.

So I go upstairs and I don't really think any of it and I'm sitting in my room. It's about 11:30 now and it began again, this very distinctive whistle like a song or a tune. So now I'm sure this is my brother so I go to tell him to quit with the whistling as it was becoming annoying, but to my shock he was asleep! So I go back to my room a little freaked out and when the whistling begins again this time I actually start shaking. Literally everyone in the house is asleep and there's no way it could have been my parents. Their room is on the other side of the house and it sounded as if this whistle was coming from outside my room!

This continued to happen for 10 minutes so I plucked up some courage, went downstairs, checked all of the appliances, the TV, the oven, etc. I wanted some way of finding a logical explanation but I just couldn't find one. As I was downstairs the worst part is that the whistling sound was now coming from the living room. It's as if this sound was following me around the house. If I was freaked before I was now shiat scared. I ran upstairs, put my earphones in and tried to sleep.

The next day my mother said it was probably just the wind and, granted it was a rainy windy night, but this whistle was so loud and it was a distinctive tune. What the tune was I've no idea but there's no way that was the wind. I'm convinced that it was something paranormal. What was strange was that I've been in this house for 13 of my 16 years living and nothing like this has ever happened.

Tell me what you guys think. I'd really appreciate any input or ideas as to what it was.