Isla Rasa: An Island Full of Birds in the Sea of Cortés

Isla Rasa is a tiny island in the Gulf of California, Mexico. It is the breeding site of 95% of the worlds population of Heermanns Gulls (Larus heermanni), and Elegant Terns (Sterna elegans) as well as a very large population of Royal Terns (Sterna maxima).



These migratory seabirds come from thousands of miles away. The gulls migrate from the Pacific coast from southern Canada to southern Mexico and the terns migrate from the South American Pacific. During the summer, after the birds have settled into the nesting areas, the island is literally covered with birds engaged in the timeless rituals of reproduction.

In the middle of the 20th century, excessive egg collection drastically reduced the seabird population. Fortunately several Mexican and US conservationists helped to classify the island as a protected area in 1964. One very passionate Mexican scientist, Dr. Enriqueta Velarde, is now at the helm of Isla Rasa conservation. In continuously conducting research on the island, she has not only helped protect the seabirds and provide us with valuable science, but she has provided a training ground for students interested in conservation.

Isla Rasa is barely a mile across and only one hundred feet at its highest point yet it is home to up to a million birds during nesting season.



In April and May of each year one of North America’s great concentrations of wildlife descends upon the island.

Elegant Tern (Google)
Elegant Tern (Google)


Heerman’s Gulls, Caspian Terns and 90% of the world’s population of Elegant Terns all fight for space and survival in a cacophony of wildlife.

Caspian Tern (Google)
Caspian Tern (Google)


Only a handful of travelers and researchers visit the island each year and the place is strictly protected as bird sanctuary.

Coronado Islands, offshore of the US-MEXICO border, Pacific Ocean, Baja California, Mexico
Coronado Islands, offshore of the US-MEXICO border, Pacific Ocean, Baja California, Mexico (Ralph Lee)


The islands remote location makes it ideal for the birds, but challenging for people.

Small ships with expert birding guides are the perfect way to visit Isla Raza with minimal disturbance to the birds.

isla rasa
Isla Rasa (Google)

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