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Masked Booby Sula dactylatra
The Nazca Booby Sula granti was recently split from the Masked Booby. Most published records were made before this split was made, so the distribution of the two forms at sea is still not fully known. Nazca Booby would be expected to be the main species on the Pacific coast and Masked Booby would be the one expected on the Caribbean coast. However, the distribution of the two forms is not as simple as this because Masked Boobies are also found in the Pacific. The main way to tell the two forms apart is by bill colour; Nazca Boobies have an orange coloured bill, while Masked Boobies have a yellow coloured bill. Bonta and Anderson describes them as uncommon off the Caribbean coast of Honduras, with no records before 1974 (when they were reported by Brown and Monroe, 1974). Land gives no records for the Caribbean coast of Guatemala. They are clearly an uncommon bird in the area, with Jones giving only four records for Belize, which is relatively well watched by birders.