Nathan Fillion, a brilliant actor, coined this famously popular original phrase. "FTB", or "FEED THE BIRDS", is used as a way to congratulate, or give props to someone. Here is its meaning as he describes it on his NathanFillion on Twitter page:
"This is the new High Five. It is called: FEED THE BIRDS."
Nathan Fillion, the extraordinarily talented, hot, handsome star of "Firefly", "Serenity", and "Castle", just to mention a few of the fine roles of this Emmy-winning performer, also says "Feed the birds" in his show "Castle".
Nathan Fillion: "Just did a Feed the Birds in episode three of Castle. Also, tried to squeeze in obscure Firefly reference. Bam, said the lady."
Nathan Fillion: "First, an Emmy, dinner with friends, wrap it up with @thedanband. Let's call it a perfect evening. Feed the birds." (FTB).
Nathan Fillion: "Interesting. Guest star was supposed to call me Castle, but instead called me Captain. Feed the birds." (FTB).
Nathan Fillion: "I saw so many of you have donated to the Children's Hospital Triathlon... I'm thrilled. And touched. Thanks. Really, really thanks... you. Feed the birds, all of you. Extra feed. Extra birds."
Query: When you say "Feed the birds", are you the feeder or the fed?
Nathan Fillion: "The person getting props gets fed."