Isla Rasa and Isla San Esteban
We awoke to a cacophony of bird sounds and a myriad of birds flying all around the ship, a surround-sound experience among pink-tinged clouds. During the night, we had moved from one remarkable bird island to one of the most extraordinary – Isla Rasa. Rasa (Spanish for flat, the island lives up to its name) encompasses only 142 acres, but is the breeding site for 95% of the world’s population of elegant terns and Heermann’s gulls – approximately 260,000 Heermann’s gulls and 180,000 elegant terns.
In the warm, early morning light, we boarded our fleet of Zodiacs to explore the island’s shoreline. Isla Rasa is a very important seabird breeding island where these terns and gulls return annually for courtship, mating, and to nest and raise their young. As we paralleled the rocky coastline, the sounds engulfed us. There were many Herrmann’s gulls along the shoreline, as well as pelicans, royal terns, osprey, American oystercatchers and Sally Lightfoot crabs. We watched as swarms of birds flew on and off the island. Thousands of hormone-infused elegant terns cavorted along the low rocks in a flurry of activity.
We were not the only ship arriving at Isla Rasa today. The Mexican Navy was bringing Enriqueta Velarde, the researcher who has spent the past 30 years studying Rasa, to the island along with supplies necessary to live there for the coming months of research. Her research data on the seabirds’ success and failures have been used to both predict and inform regional fisheries. The National Geographic Sea Bird lent assistance with Zodiacs shuttling boxes and boxes of supplies, and many, many containers of potable water, ashore.
After breakfast, the tide was high enough for us to enter the lagoon to go ashore. In broad, sandy open areas, thousands upon thousands of Heermann’s gulls had already established nests and were sitting on eggs, squawking at their neighbors, and occasionally fighting over nesting sites. Enriqueta gave us a briefing on the island and her long-term research here. We felt privileged to visit, as very few people ever get to see, much less land, at Isla Rasa. It was a stunning morning.
Early afternoon found us sailing to Isla San Esteban in beautiful calm waters. As we made our transit southeast from Rasa, sperm whales could be seen in many directions, logging on the surface. Once ashore on San Esteban, we carefully made our way along the rocky cobbled beach so as to not disturb the nesting yellow-footed gulls sitting on eggs. We entered the sandy arroyo to walk and look for the spiny-tailed iguana, and the endemic pinto chuckwalla lizard. We were very lucky to see them both as the late afternoon sun moved closer to the island’s mountain ridge.
We pulled anchor for the long sail south in absolutely flat calm seas. Pacific loons and Craveri’s murrelets with tiny chicks left skittering trails in the sunset light.
Ahhhhh, what a day.
