The human history of Alcatraz captures the imagination, but its natural history is just as fascinating. Long before people set foot on The Rock, it was home to thousands of nesting birds. In the 1770s, Spanish explorer Juan Manuel de Ayala named either this island or neighboring Angel Island—no one is sure—Isla de los Alcatraces, or “island of the pelicans,” due to its abundance of seabirds. Human activities from 1850 onward drove out the birds, but soon after Alcatraz Prison closed in 1963, the avian residents returned. Today, more than 5,000 nesting birds call Alcatraz Island home.
What birds you will see depends on the month of the year and what parts of the island are open to visitors. Seabird nesting season begins around February 1 and continues until August, although the greatest activity occurs between April and June. Depending on your timing, you might see courtship rituals, nest building, and/or parents rearing their young.
In February, Western gulls return each year to claim their territory and raise their young on the island’s historic parade grounds below the Alcatraz lighthouse. Gulls build more than 500 nests on Alcatraz each year, making this one of the largest nesting sites for Western gulls on the West Coast. By June, the crumbling concrete is covered with chicks.
In April and May, black-crowned night herons and snowy egrets build their nests in shrubs, trees, and bushes around the island. You can often see them near the parade grounds or along the island’s West Road.
For most birders, the coveted prize is a sighting of Brandt’s cormorant, a West Coast seabird that spends most of its life far out to sea, diving into the ocean for food. The male’s breeding plumage includes a gorgeous blue throat patch, which he shows off by pointing his beak up toward the sky. As many as 2,000 pairs nest on Alcatraz’s rocky outcrops every spring.
Want more? Walk anywhere on the island and you might get a front-row-center view of pelagic cormorants, Canada geese, and mallards. Pigeon guillemots are easily seen near the island’s dock; they nest in broken piles of concrete and masonry. You can spot plenty of songbirds, too: White-crowned sparrows, golden-crowned sparrows, and song sparrows make their homes in shrubbery and decaying concrete. Yellow-rumped warblers and Townsend’s warblers are also common island visitors.