Peruvian Booby

A Peruvian Booby preening its feathers near its chick on a small rocky island. Image taken off the coast of central Chile.

Boobies really do get the short end of the stick when compared to other seabirds. Even their common name shows a complete lack of respect for the bird. The name booby comes from the Spanish word bobo, which means clown or stupid fellow. There are a couple guesses as to why they were called this. Possibly because these animals were not easily scared off by humans and so were easy to catch by sailors looking for dinner. Another thought is because they have a really funny looking courtship dance, where they walk around lifting their feet up really high and throwing their heads back and clacking beaks. Whatever the case, no respect for the boobies.

Boobies are actually fantastic divers. Peruvian boobies will dive from 15 meters (~50 feet) in the air down into the sea. They dive so deep that they usually pass the fish they are hunting on the way down and instead catch them in their beak on the way back up. Because they dive so deep, they have access to fish that other sea birds can’t reach and so they are frequently the victims of piracy, or having their food stolen from them. In this case, the pirates are other sea birds that can’t dive as deep, such as gulls or pelicans, and are usually juveniles that aren’t very good at foraging yet. And frigate birds are some of the worst pirates as well. The scientific name for the behavior of stealing food from another animal is kleptoparasitism. Isn’t that the best word ever?

Boobies even get trouble from other boobies. Sometimes these birds will chase other boobies around until they regurgitate and then the chaser can steal the meal. Even when they’re chicks they have to worry about other boobies. And not just strangers, but their own kin!  Since boobies lay their eggs a few days apart, one chick is usually much larger than the other and in some species, the larger chick will eject its sibling from the nest, essentially killing it. What’s interesting is that blue footed booby parents will prevent their older offspring from killing the younger, while the masked booby does not. Scientists believe it’s parental supervision that is the difference because if you put blue footed booby chicks in a nest with masked booby parents, one chick will kill the other. And if you put masked booby chicks in a blue booby nest, the siblicide is not allowed. For the record, boobies are not the only birds that engage in siblicide.