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Avian migration

Twice a year, billions of birds cross North America, mostly at night. Florida is a runway, a fuel stop and a winter home.

Photo: Brent M. from Sedro-Woolley, usa · Wikimedia Commons
Four flyways and five migration routesA simplified map of North and South America with the Pacific, Central, Mississippi and Atlantic flyways shaded, and routes for the red knot, ruby-throated hummingbird, Arctic tern, sandhill crane and purple martin.PacificCentralMississippiAtlanticBradenton, FLred knot: Arctic Canada to Tierra del Fuego, about 15,000 km each wayruby-throated hummingbird: Eastern U.S. across the Gulf to Central AmericaArctic tern: Arctic to Antarctica along the Atlanticsandhill crane: Prairies to Texas and Florida (Florida also has its own non-migratory cranes)purple martin: Florida and the East to Brazilred knotruby-throated hummingbirdArctic ternsandhill cranepurple martin
The map

Four flyways, five routes

Birds funnel along coasts, rivers and mountain chains. Biologists group these into four flyways: Pacific, Central, Mississippi and Atlantic. Florida sits at the bottom of the Atlantic flyway, the jumping-off point for birds crossing to the Caribbean and South America. Dots move along each route; they stop under reduced motion.

Red knot NTNear threatenedRuby-throated hummingbird LCLeast concernArctic tern LCLeast concernSandhill crane LCLeast concernPurple martin LCLeast concernSwallow-tailed kite LCLeast concern

How do they find the way?

  • Magnetic sense: birds sense Earth's magnetic field, perhaps through proteins in the eye.
  • Stars: young indigo buntings learn the night sky's center of rotation (Emlen's planetarium experiments, 1960s-70s).
  • The sun: an internal clock lets birds use the sun's position as a compass.
  • Landmarks and smell: coastlines, rivers and mountain ridges; some seabirds use smell.

Florida as a stopover

In spring, warblers and tanagers crossing the Gulf land exhausted on the first coast they reach; when a cold front meets them, thousands can "fall out" at once at places like Fort De Soto Park near St. Petersburg.

Fuel

Before the Gulf crossing a ruby-throated hummingbird nearly doubles its weight in fat. Red knots time their May stop in Delaware Bay to the horseshoe-crab spawn.

Lights and glass

Night migrants are drawn off course by city lights and hit windows. Scientists estimate up to about a billion birds die from building collisions in the U.S. each year (Loss and others, 2014, est.). "Lights Out" programs and patterned glass help.

Not every bird goes

Florida sandhill cranes, Florida scrub-jays and northern cardinals stay all year. Some species are partly migratory: northern cranes winter here beside resident ones.

Watch it live. BirdCast forecasts each night's migration from weather radar (Cornell Lab and partners). eBird maps what birders see today. Audubon's Bird Migration Explorer follows hundreds of species.
Grades K–5

Where do birds go in winter?

Many birds fly south where it is warm and there is food. They find the way using the sun, the stars and a hidden sense of north. Some tiny hummingbirds fly over the whole Gulf of Mexico without stopping!

For classes
Grades K-2
The Nest: Count the birdsPreview
Grades 3-5
The Bird Aviary: Two habitats, one railPreview The Bird Aviary: Count properlyPreview
Grades 6-8
Ecosystems: Watch the Live CameraPreview Ecosystems: Crowded Cups and LimitsPreview
Grades 9-12
Ecosystems and the Human Body: Populations and carrying capacityPreview

Drawer: Zoo: Avian migration QR SGRVJH

Quiz: Avian migration quiz · 7 questions

Next door: Wetlands and coasts · Natural history: bird room

Sources

Checked November 2026. Figures marked (est.) are estimates; statuses are flagged in the catalog for re-checking against the live IUCN Red List before acceptance.

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