From 1999 to 2001 we made the first thorough bird surveys of Farallón de San Ignacio, an islet off Topolobampo, Sinaloa. The islet hosts 100–200 nesting pairs of the Red-tailed Tropicbird, about 1,200 Brown Boobies, 1,400–1,650 Blue-footed Boobies, and about 1,000 Heermann’s Gulls. The Double-crested Cormorant and Yellow-footed Gull nest irregularly in small numbers.