🦅 The Great Animal Migrations

What you’ll learn

1. The Navigator's ToolkitUnderstand the documented navigation senses animals use, from magnetic and sun compasses to stars, smell, and learned landmarks, and how they work together.Migratory animals navigate using multiple documented senses. Many read Earth's magnetic field, others use a time-compensated sun compass or a learned star compass, and some build maps from smell or memorized landmarks and routes. Lab and field experiments have teased these systems apart. The key lesson is redundancy: animals carry a toolkit of cues and cross-check them, so if one fails, others take over.
2. The Epic JourneysLearn the great documented migrations, including the Arctic tern, Serengeti wildebeest, monarch relay, salmon homing, and gray whales, and why animals migrate at all.The Arctic tern holds the record for longest annual migration, chasing summer pole to pole. Over a million wildebeest circle the Serengeti following the rains, monarchs reach Mexico across several generations, salmon return to their birth streams, and gray whales hug the Pacific coast. Animals migrate because seasonal shifts in food and safe breeding sites make the costly journey pay off.
3. Built for the JourneyExplore the documented physiology that makes extreme migration possible, including fat storage, organ remodeling, sleeping in flight, and riding wind and thermals.The bar-tailed godwit makes the longest nonstop flight, crossing the Pacific in over a week by storing fat past half its weight and shrinking unneeded organs. Frigatebirds sleep on the wing, often with half the brain. Migrants ride tailwinds and thermals to save energy, and endurance feats span turtles, tuna, and caribou. These animals operate at the edge of the possible, which also makes them vulnerable.
4. Timing and a Changing WorldUnderstand how migration timing is tuned to seasonal food, how climate change causes phenological mismatch and breaks stopover chains, and what the honest data show.Migration depends on precise timing, with animals often cued by day length to hit a food peak triggered by temperature. As warming shifts spring earlier, migrants can arrive out of sync, a documented mismatch that has driven declines. Journeys also depend on chains of stopover sites, where losing one link can strand a population. Many long-distance migrants are declining faster than residents, though some are adapting.
5. How We KnowLearn the documented methods behind migration science, from bird banding to geolocators, satellite tags, isotopes, and radar, and how tracking serves conservation.Migration science began with bird banding, which gave sparse data but established tracking known individuals. Light-level geolocators later let scientists follow small birds across whole journeys, revealing feats like the Arctic tern's true route. Satellite tags, stable isotopes, radar, and radio-tower networks now map animal movement in detail. This data underpins conservation, and genuine mysteries, like the monarch's navigation, still remain.

Questions this course answers

Grounded in trusted sources

• Cornell Lab of Ornithology
• Smithsonian Institution
• National Geographic
• Max Planck Institute of Animal Behavior

Every Wunder lesson is built from real, reputable sources — never invented.

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