Some of the birds in this photo gallery are year-round residents in this region of California, but many arrive for the winter only while others just pass through on their journey north or south.
Each year at least a billion birds migrate along the Pacific Flyway, which stretches from the North Slope of Alaska to the Pacific Northwest, California, Mexico, and Central and South America. But these birds are only a fraction of those that used the flyway a century ago. Some species, such as the Black-footed Albatross and the Least Tern, are in serious trouble, and even many common birds, such as the Western Sandpiper, have become far less common. Habitat loss, water shortages due to diversion for agriculture and development, diminishing food sources, and climate change all threaten the birds of the Pacific Flyway.