This is the post of a newbie birder. Lots of birds are involved, and hopefully all of them are correctly labeled.
We spent about four days in Mazatlán. Next stop, Isla Isabela, a tiny island considered the Galapagos of Mexico. The island is maybe half a mile by a mile and a half. It has an old research station that is now used by ecotours who come to the island for diving and snorkeling. Isabela is also the home to thousands of Magnificent Frigate Birds, boobies (Blue Footed and Brown), and Red-billed Tropicbirds, iguanas and a snake species that we didn’t see.
Also flying among the magnificent frigate birds were four red-billed tropicbirds. They were smaller and louder than both the frigates and the boobies, and they were easy to pick out overhead because they were frantically flapping their wings most of the time they were in flight. They must have flown circles around the boat for a at least twenty minutes.