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Flight and Migration

Delve into the fascinating world of bird migration, from feathers and molting to the reasons behind these incredible journeys and the hazards they face. Learn about navigation factors, established flyways, and methods for studying migration patterns.

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Flight and Migration

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  1. Flight and Migration “If I had to choose, I would rather have birds than airplanes.” - Charles A. Lindbergh

  2. Feathers • Modified from epidermis – lots of keratin protein (as in scales, nails, skin, hair) • Function: • Insulation • Flight • Regulate body heat (endotherms) • Sexual display

  3. Types of Feathers • Down - irregular shape (dead air space) • Contour - give body a smooth, aerodynamic shape - some are specialized specifically for flight

  4. Feather Structure

  5. Molting • Feathers are a dead structure (analogous to hair in humans) • Molting essential to replace worn feathers • Kinds of molts • Complete (patchy look) • Partial (gradual) * Molt 1-2 times/year (lots of energy spent)

  6. Migration • Migration = the regular, seasonal shift of birds from one region to another (Instinctive) • Origins of migration: • Glacial era • Ancestral home in tropics • Went north to avoid crowding when breeding • Stimulus to start migration (“Biological Clock”) • Inherent in hormones, related to length of daylight

  7. Why Migrate? • Adequate supply of food (or enough daylight to find it) • Favorable climate in which to live • less stress on thermoregulation and young • Most migrations are latitudinal (N-S) • Some permanent residents – tropical birds • Some far north to far south (ex. Artic Tern 11,000 miles one way!!)

  8. Factors Used for Navigation • Topographical features • Position of sun (starlings and pigeons) • Star patterns • Magnetic fields • Prevailing winds • Sounds and smells

  9. Routes • Well established flyways • Blue Goose (James Bay Louisiana 5,000 km nonstop) • Ruby Throated Hummingbird (1000 km across Gulf of Mexico * Arrivals are often very precise and can range from slow (4 months) to fast (several weeks)

  10. Routes

  11. Hazards to Migration • Hunters • Planes • New predators • Storms • Population densities

  12. Studying Migration • Tagging/banding • Radar

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