Beatles observation

Here's a Beatles observation for you: anytime there is non-lyrical melodious filler, you can be sure it's Paul, and never John. Any whistling, or "doo do doo", or humming--always Paul. I don't think there's even one instance of John doing this (or George, but I'm not as sure about that).

Examples:

• Mother Nature's Son ("doo do doo do doo do...")
• Your Mother Should Know ("da da da..")
  
• Fool On the Hill (instrumental verse; "oh oh oh ohhhhhh round round round...")
• Hey Jude ("na na na na na na naaaaaaaaaaaa...")
• Rockey Raccoon ("da da dada da daaaa"; "do doo do do dooo do")
• Honey Pie (instrumental segment/"I like this kinda, kinda muuuuuusic"; "oh ho ho ho ho hoo ho")
• I Will (humming)

I'm sure there's lot of other examples.

Anyway, if someone knows of a John song (or John part of a song) with similar melodious filler, I'd like to hear it.