When a director makes a movie, there are often scenes planned--and even filmed--that end up on the cutting room floor during the editing process. There are various reasons: a scene doesn't fit in with the overall pacing of the story, time constraints, budget deficits to finish effects, etc. The same goes for a TED talk. I had originally written in some of the more surprising things I learned with my Barn Swallows, but my talk was three minutes over the my allotted time and I had to make some cuts that weren't contributing as much to the overall message.
So, I present to you one of my own deleted scenes, "fecal sacs". Watch the video below and then imagine in your head the narration I give for it:
Hopefully your food has settled from lunch because this part gets a little gross. Sometimes when we watch nature shows wildlife is often portrayed in a warm, fluffy way. But every once in a while I’d observer something peculiar. It turns out that nestlings don’t wear diapers. They have to grow so fast, however, that they have to be constantly fed. But that mess has to go somewhere.
What I didn’t expect is this: That’s right, mom and dad eat it. These nestlings’ digestive system are very immature when they first hatch and so most of the nutritional value of the bugs they're fed isn’t fully extracted. They defecate what are called "fecal sacs" that, for the first several days after hatching, are eaten by their parents. Since the parents are expending most of their waking moments foraging for food for them, they run their baby’s meals through a second time to get some of the value out of the food that they’re not directly eating because the nestlings are consuming most of the food they gather.
For additional information, here's an obligatory Wikipedia link to the fecal sac article.