This bird is a long way from its nest.

Filmed in 2010, the video shows a black-headed cardinal feeding seeds to very eager goldfish. According to the video's description, the bird would fly down as many as six times a day, depositing seeds into the open mouths of the fish.

It's a confusing sight for sure, as you're expecting the bird to be doing this behavior way up in its nest. So why is it on the shore of a lake, feeding fish?

Speaking to National Geographic, Princeton biologist Christina Riehl suggests it could be the bird's innate desire to mother. "My best guess is that the appearance of the goldfish's open mouth at the surface of the water is just similar enough in size and shape to the open mouth of a baby bird that it triggers the instinct in the adult bird to provide food to it."

"It's an amazing demonstration of how simple stimuli can trigger very hardwired behaviors, even in situations that seem obviously wrong to us," she says.

It's not the only instance in recent memory of inter-species feeding, either. In July, a lioness in Tanzania was spotted nursing a leopard cub, an "unprecedented" pairing.