Funny idea, but a little bit too simple really. I feel if the picture isn't cartoonish, those speech bubbles ruin it every time. Better choice would be to put the text on the lower part of the image, if at all. The shadow isn't very accurate, but It would be almost a straight line like with the bird really, because of the sign orientation.. don't know if it really matters here.

lol...

you could change the one on the sign to a flying seagull

If the bird is smart enough to look at a sign and think.. "what does that mean ?"... It's gonna know what 60 means.
Also, it appears to be looking at the back of the sign at a pole.

I agree with elficho about the sign....or else you can also make the sign of no stading like we have no parking sort of thing....Would be better...But a nice try....

LOL ,funny!

nice