These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
The birds finding out about their shadows and being convinced that they're real. The episode has a number of funny moments, but one that stands out would be Chirp trying to feed her shadow because it "looks a little flat". Even the narrator thought it was funny!
Chirp: (drops some seeds onto her shadow) You simply must try these seeds from the forest. They are quite delicious!