Migration Patterns

Record breakers

The Arctic tern breeds in the far north and spends the northern winter in the Antarctic. Tracking studies show individual birds covering roughly 70,000 km in a year, the longest regular migration known. Sooty shearwaters trace a vast figure-eight around the Pacific Ocean between their breeding grounds in the south and feeding areas in the north.

Why they travel

Seabirds follow food. Plankton blooms, upwellings and seasonal fish runs move with the seasons, and the birds move with them. Many species breed where predators are few, then leave for richer feeding grounds once the chicks fledge.

How we know

For most of history, migration routes were pieced together from ringed birds found far from home. Today, lightweight geolocators, GPS loggers and satellite tags record a bird's route directly. Shared tracking databases now combine data from thousands of birds and hundreds of studies.

Flyways

Coastal birds use broad routes called flyways, such as the East Atlantic Flyway and the East Asian–Australasian Flyway. Stopover sites along these routes, such as tidal mudflats, are critical. Losing one can affect birds across half the planet.