Pelicans are among the largest and most recognizable aquatic birds in North America, known for their massive bills and impressive throat pouches. While often associated with warm coastal environments, many populations undertake extensive seasonal journeys. The precise timing and routes of these movements depend heavily on the species and their geographical location. These complex behaviors are driven by the availability of food and the necessity of reaching specific breeding sites.
Identifying the Migratory Pelican Species
The timing of pelican migration depends on the species, as only one of the two North American species is a long-distance migrant. The American White Pelican (Pelecanus erythrorhynchos) is highly migratory, traveling vast distances between its inland breeding grounds and its southern wintering range. These birds breed across the interior of the continent, from the Canadian prairies down to the Great Basin and Great Plains of the United States.
In contrast, the Brown Pelican (Pelecanus occidentalis) is largely resident and non-migratory throughout most of its coastal range. Only northern populations along the Atlantic and Pacific coasts exhibit seasonal movements. These movements are often short, erratic dispersal flights in response to localized food shortages or severe weather. Therefore, the discussion of calendar timing primarily concerns the American White Pelican.
Seasonal Timing of Migration
The American White Pelican adheres to a fixed calendar for its annual movements, with spring migration beginning as early as late winter. The northward journey to breeding colonies typically starts in February and March for the earliest arrivals in the southern U.S. states. Birds reach breeding sites in Utah and Nevada by March. Those flying further north to the Canadian prairies arrive later, usually in April or early May, often before inland lakes have fully thawed so they can secure nesting sites.
The southbound migration in the fall is generally more spread out than the swift spring movement. Pelicans begin departing northern breeding territories around September, continuing through October and into November. The main migratory pulse occurs during these two months, though some stragglers are observed as late as December in milder climates. Northern Brown Pelican populations also head south in autumn and return north in March and April.
Routes and Destination Factors
The geographical routes and destinations for migrating pelicans are determined by the location of their breeding and wintering grounds, creating distinct patterns east and west of the Rocky Mountains. Populations breeding east of the Rockies follow a corridor that takes them south and east, often utilizing major river valleys as navigational aids. Their primary wintering destination is the Gulf of Mexico coast, extending from Florida to Mexico.
Pelicans breeding west of the Rockies move predominantly southward toward the Pacific coast of California and Mexico. The trigger for the fall departure is the ecological pressure of dwindling resources and changing weather conditions. The freezing of northern inland lakes and rivers makes fishing impossible, forcing the birds to seek open-water foraging areas in the south.
The spring return flight is driven by the need to reach established breeding colonies. These colonies are typically found on isolated islands in large freshwater or saline lakes, which provide safety from terrestrial predators. During migration, pelicans often use rising columns of warm air, known as thermals, to gain altitude and glide long distances, conserving energy.