bats

Bats eat a lot of bugs — up to two-thirds of their body weight in insects daily for some species. There's an unexpected side effect of all that insect eating, though. Bat scat is described as "sparkling with insect exoskeletons." Generally the words "sparkling" and "feces" aren't found together, unless you have a toddler that's gotten into a jar of glitter.

It's a diet of insects that puts the shine in bat guano. Insects' exoskeletons, or hard outer coverings, are made of chitin. Chitin is chemically a lot like plant cellulose; it's difficult to digest, and passes through a gut relatively unchanged. If you eat a lot of shiny insects, you are going to produce Twinkle Turds.

Toads have been known to eat bats, although usually only when they happen upon one opportunistically, said Rachel Page, a researcher at the Smithsonian Tropical Research Institute in Panama who wasn't involved in the present finding. However, some toads and frogs will systematically wait outside of caves and catch bats as they emerge from the roost at night, Page wrote to LiveScience in an email. This has been seen in Australia, she said.
However, bats are not always the victims in this animal-eat-animal world — certain species, like fringe-lipped bats (Trachops cirrhosus), have been known to eat toads.

His relationship with Robin makes sense now too.