Blue Footed Boobies

Two courting blue-footed boobies in a dwarf cardon cactus-fringed canyon. The males have noticeably smaller pupils than the females.

Tens of thousands of brown boobies nest on the island as well.

Blue-footed boobies atop walls from the old mining settlement

A female blue-footed booby and chick

A very young chick in a blue-footed booby nest

A blue-footed booby tends to its young chick

A female blue-footed booby with a downy chick

A male blue-footed booby outside a rocky crevice.

Boobies have asynchronous hatching, meaning the the first egg is produced (and thus first chick hatched) significantly earlier than subsequent eggs. This results in a size disparity between the chicks. The older chick will often harass the younger. This behavior is not stopped by the adults in the nest. Called facultative siblicide, it may result in the death of younger chicks, especially in times of food scarcity.

A downy blue-footed booby chick begging for food

A downy blue-footed booby chick stretching its wings over an unhatched egg in its nest.

Blue-footed booby nests in close proximity on a rocky outcropping

Female, downy chick, and an unhatched blue-footed booby egg. In all likelihood this egg did not hatch. It was a season of severe food shortage due to El Niño conditions, and the parent appeared to have disregarded it.

A blue-footed booby chick being fed

A male blue-footed booby performing courtship behavior.

Blue-footed and brown boobies in the sky above Isla San Pedro Martir. In a typical nesting year, one would expect to see tens of thousands of birds overhead at any moment. Due to El Niño conditions and a subsequent shortage of sardines (their primary food source), the island was eerily quite and had a very low number of active nests.

A blue-footed booby helps its chick preen their downy feathers.

Male and female blue-footed boobies during courtship behavior.

A blue-footed booby coming in for landing in a rocky canyon.

A blue-footed booby chick gular fluttering to keep cool in the heat of the day

A pair of blue-footed boobies with down stuck to their bills from a preening session.

A downy blue-footed booby chick tending its nest

A male blue-footed booby preparing to land among the cactus