This story appears in the January 2018 issue of National Geographic magazine. For the care and feeding of its offspring, the common cuckoo outsources. When she’s ready to lay an egg, a female ...

2010). These and other cuckoo hosts appear to have evolved a simple rule of thumb to direct their behavior: "eject the egg unlike your own". But how does a bird know what its own eggs look like?

However the cuckoo catfish eggs develop quicker, hatching first, whereupon the catfish fry either eat the cichlid fry in the mouth of their mother to be, or cause her to eject her fry prematurely.

The U.S. Fish and Wildlife Service proposed today to protect Suckley’s cuckoo bumblebees under the Endangered Species Act. This decision comes in response to a petition and legal action by the Center ...