I’m an okay whistler but you should see me hum!
Yes. In fact, I can whistle the parts you hear on recordings perfectly. Stuff like Billy Joel’s “The Stranger” or The Scorpions “Winds of Change” for example.
I can, not always well, but I can.
I can but my range is limited so my ability to whistle a full tune is not great.
Semi-amusing anecdote about what might cause one to not be able to whistle: About 24 years ago, I was pregnant with my first child. My nephew, P, was about five years old. He was staying with my mother, and we were all going out to grab something to eat. P wanted me to carry him. My mother said “Honey, norinew can’t carry you, because she’s pregnant”. Once in the car, he wanted to go, well, I can’t remember where, but somewhere my body was telling me I shouldn’t eat just then. Mom said “Honey, norinew can’t eat there right now, because she’s pregnant”. A little bit later, he asked me to whistle something for him. I said “Oh, honey, I can’t whistle!” He said “What? Not cuz you’re pregnant?” 
I’m another one who can whistle - very well - in the normal embouchure - but can’t do the two-fingered piercing whistle. When I was a kid, for some reason only the naughtiest kids could do that.
I can also whistle without the embouchure, just by curling my tongue; I don’t think that’s uncommon.
My Dad also said whistling was only for boys.
It amused me. 
I can whistle, but my abilities vary randomly from day to day. Some days, I’m pitch perfect; others, not so much.
I haven’t yet figured out why (has nothing to do with degree of moistness in lips/mouth).
Anyone else encounter this?
mmm
I Was Kaiser Bill’s Batman…
I can whistle a tune through my mouth and also whistle most of a tune by blowing through my cupped hands.
I can also slap out a melody on my throat or knock one out on the top of my head.
Oddly, I can remember being a little kid in my parents’ kitchen and asking my mom how she whistled. So there was a time when I couldn’t do any of this.
And I’m the only one in my family who can’t whistle.
I not only can’t whistle, I hate it whan anyone around me does. Even the best whistler hurts my ears. I don’t think it’s simple jelousy, I didn’t like it when I was a baby, according to my family.
I can whistle like a motherfucker…and shit.
This here is the song that I learned to whistle to when I was a kid…the high notes and harmonies are pretty challenging.
Anyone that is a little older and a whistler will recognize this song…I had an old K-Tel record with this on it.
I can whistle with great enthusiasm. I do the Great Escape theme, or Monty Python’s Sit on My Face.
I can’t sing, though. Is there any correlation between ability in whistling and singing?
FoieGrasIsEvil, I’m totally going to learn that.
I can only whistle when I inhale. And I can’t snap my fingers either. I guess I just gotta be different or something.
I can’t really whistle a tune because I can only inhale so much before having to stop and breathe out which totally messes up the rhythm of a tune.
Never mind, more or less double post, brain not engaged.
LOL, there’s one stereotype that doesn’t hang, sorry! 
Seriously, I whistle all the time, and quite well, I think, to the point where when I was a kid my dad used to joke that someone would paint a picture of him and call it Whistler’s Father.
Three of my favourite achievements:
- the third Brandenburg Concerto;
- “Jesu, Joy of Man’s Desiring”;
- the penny-whistle part from “You Can Call Me Al.”
I can make a very weak sound by curling my tounge against the roof of my mouth. It is not what I would call a whistle, and I cannot vary the pitch.
I can, however, wiggle my ears - it really freaks people out to see an ear bob up and down a half-incg.
(there are tiny muscles running from the top rear of the canal at about 45 degree up and back - why/how I learned how to flex these I do not know)
me as well as a high pitch whistle (is there a different name for that).
Despite determined effort, I couldn’t whistle when I was young. I have an elevated palate, which might have something to do with it.
Now I can whistle equally well in or out.
ETA: I can’t do the fingers-in-mouth superwhistle, and I am incredibly jealous of people who can.