kitties and such. No, I am totally making that up. But, like many animals, they are opportunists; if food is available, they will snack away.
Is that snow on this female cardinals beak or bits of brains? Pic by Charles Creamer.
Later in the day, when she and Lynnanne Fager looked out the bird window to see what species were there, they witnessed an amazing thing. Right out of a horror movie for rodents, a Northern Cardinal had grabbed the dead mouse and was eating its head. Now I have heard of zombies eating heads and brains and such, but not our chipper little cardinals! You can view the photos here.
Checking a few sources, I found out this is not the norm, but not unheard of. Birds of North America Online does not mention cardinals eating mice. They eat 29% animal matter, mostly insects, and also spiders, slugs, snails, centipedes and bivalves. 71% of their diet is plant based, mainly berries and seeds. They referenced a paper by W. L McAtee from 1908 called the Food Habits of Grosbeaks.