Bird migration is a fascinating phenomenon that involves birds undertaking long distance journeys across continents or oceans in order to find areas with more favorable conditions or resources. Many species of birds migrate huge distances every year, some traveling thousands of miles between their breeding and wintering grounds. But just how long are these marathon flights that migratory birds undertake?
How far do migratory birds travel?
The distances covered by migratory birds during their annual migrations can be astounding. Here are some examples of extreme migratory journeys:
- The Arctic tern flies from its Arctic breeding grounds all the way down to the Antarctic coasts every year, undertaking a round trip of around 44,000 miles.
- The bar-tailed godwit flies non-stop for 6,800 miles from Alaska to New Zealand without pausing.
- The tiny blackpoll warbler flies non-stop for up to 90 hours and 2,300 miles over open ocean from New England to South America.
- Swainson’s hawks migrate over 6000 miles between North America and South America annually.
- Red knots fly thousands of miles between the Canadian Arctic and South America every year, one of the longest migrations in the bird world.
As these examples show, migratory birds are capable of astonishingly long migrations spanning thousands of miles between their seasonal habitats. Their extreme endurance allows them to fly such huge distances every year.
How long are migratory bird flight times?
In addition to the huge overall distances, migratory birds can fly incredibly long durations without stopping during their migrations. Some of the longest recorded non-stop flight times include:
- Bar-tailed godwits – 8 days of non-stop flying over the Pacific Ocean on their Alaska to New Zealand migration.
- Great snipes – up to 4 days of non-stop flying over the Indian Ocean between Africa and India.
- Blackpoll warblers – up to 3 days non-stop over the Atlantic Ocean between Canada/US and South America.
- Brent geese – 3 days non-stop from Svalbard to Scotland (1800 miles).
- Ruby-throated hummingbirds – up to 26 hours non-stop over the Gulf of Mexico.
These extreme non-stop flight times demonstrate the incredible physiological capabilities of migratory birds. Their muscles, fat stores and oxygen carriage abilities allow them to fly for days without stopping to rest or feed.
How fast do migratory birds fly?
Migratory birds need to maintain certain flight speeds in order to complete their long journeys in time. Different species fly at different airspeeds depending on their body size and wing shape. Here are some typical airspeeds of migrating birds:
Bird Species | Airspeed (mph) |
---|---|
Arctic tern | 25-49 |
Barn swallow | 17-25 |
Bar-tailed godwit | 37-50 |
Ruby-throated hummingbird | 25-38 |
To maximize flight range and efficiency, migratory birds seek to take advantage of helpful tailwinds that boost their ground speeds. However, even without wind assistance, their airspeeds help them cover huge distances rapidly.
How high do migratory birds fly?
Most migratory birds do not fly at extremely high altitudes, as they try to balance energy use against wind patterns and other factors. Some typical migration flight altitudes include:
- Geese and ducks – <2000 feet
- Songbirds – 1000 to 5000 feet
- Wading birds – up to 5000 feet
- Raptors – 500 to 6000 feet
However, some migrating birds have been recorded flying at much higher altitudes, such as Whooper swans at 29,000 feet and Ruppell’s griffon vultures at 37,000 feet!
In general, larger birds like raptors, storks, and waterfowl tend to fly higher than smaller songbirds. But weather conditions also play a major role in determining flight altitudes.
Do migratory birds fly continuously?
While some migratory bird species can fly for extreme durations without stopping, most birds cannot fly continuously all the way between their seasonal ranges. Instead, migration involves intermittent flying and stopping.
On migratory journeys, birds utilize various stopover sites to rest and refuel. The distances between stopovers depend on the species and conditions, but may range from 25 to 375 miles for small birds. Migrating birds exhibit different flight behaviors during migrations:
- Short hops – Flying short distances between multiple rest stopovers.
- Long endurance flights – Flying for extended distances non-stop over barriers like oceans and deserts.
- Intermittent flights – Alternating between flying and stopovers to gradually progress along migration route.
While remarkable long flights get the most attention, shorter hops between rest stops are actually the most common migratory behavior for land birds over land areas. Shorter flights allow refueling and rest to sustain the overall journey.
What affects the flight distances and times?
Many different factors influence how far and long migratory birds can fly:
- Fuel stores – Body fat provides energy for flights. Birds may double their body weight before migration to build fat stores.
- Weather – Wind patterns can help or hinder flight. Some birds wait for favorable tailwinds before migrating long distances.
- Stopover habitat – Abundant food resources allow refueling for next flight stage.
- Predation – Some birds make risky non-stop flights over oceans and deserts to avoid predators at stopovers.
- Navigation – Innate abilities and mental maps help birds stay on course during long flights.
Because migration is such a metabolically demanding activity, birds have evolved optimal strategies to balance flight times and distances with energy use and stopover refueling requirements.
How do young birds handle migration?
Young migratory birds making their first journeys display amazing navigational abilities despite their inexperience. However, juveniles do often follow somewhat different migration strategies compared to adults:
- More frequent short stopovers to rest and orient.
- Slower flight speeds and shorter daily flight distances.
- Less direct routes and more deviations from main course.
- Delayed fall migration starts until energetic needs are met.
Additionally, some young birds skip migration entirely in their first year, staying in the breeding grounds year-round until they are capable of making the full journey as adults.
Effects of climate change
As climates change, migration patterns are also being affected. Some observed impacts linked to warming temperatures include:
- Earlier spring arrivals and later fall departures from breeding grounds.
- Shorter migration distances for some species as winter ranges shift.
- Greater survival threats for birds still making long migrations to traditional wintering areas.
Migratory birds serve as an indicator of climate change. Tracking shifts in migration timing and ranges gives scientists insights into the ongoing effects of climate warming on natural systems.
Conclusion
The extreme long-distance flights undertaken by migratory birds are an amazing feat of endurance. While a few species can fly for days at a time without stopping, most birds fly for shorter durations interspersed with stopovers to rest and feed. Optimal migration strategies involve balancing energetic needs and fuel stores with travel speed, stopover habitat availability, weather patterns, predation risks and navigational capabilities. Climate change is now altering migration patterns and posing new challenges for migratory birds.