Grosbeaks Eat Monarchs
It's easy to tell when a black-headed grosbeak ate a butterfly. The monarch's entire abdomen is missing. Grosbeaks do eat the cuticle. However, they prefer male monarchs who have 30% fewer toxins than do females. There are 37 bird species in the region that eat insects. Yet only the oriole and grosbeak prey on the millions of monarchs that visit Mexico every winter.