The San Francisco Bay Area network of national parks supports over 250 different species of resident and migratory birds. Situated along the Pacific Flyway, the network hosts a variety of birds that stop to rest and feed on their amazing journeys. These transient populations range from equatorial regions as far south as the South American rainforests to polar regions as far north as the Canadian arctic. Bird surveys are one of the most widespread types of long-term monitoring in the United States. In addition to being common to most habitats, birds also function as a useful indicator of habitat extent and quality.