What are the appliques made from?

I would like to make several birdseed cakes. Obviously, I can not use fondant. But what would be similar to make a very safe and pliable type of bird play-doh that is safe for birds to eat? I would like to make tiny shapes from silicone molds. Any help would be greatly appreciated.

What could have been used (as seen in the photos) that would be safe for birds to eat?

I think these are adorable, but I want them to be safely ingested. Thank you!