Fall migration has been underway for awhile now, starting as early as August for some birds. Of the 10,000 or so species of birds in the world, around 4,000 (40%) migrate. Birds migrate mainly due to the increase/decrease of resources and nesting sites. Factors that influence when a bird migrates includes genetics, day length, weather, and food supplies. Species that migrate may use annual migration routes, Earth’s magnetic field, the sun, and/or stars to help navigate their way.
There are 3 kinds of migrants: short-distance, medium-distance, and long-distance. Birds considered permanent residents do not migrate since they can find resources all year round. In North America, there are around 350 species of long-distance migrants who travel between North America and Central/South America.
Migration is a very dangerous time in a bird’s life. There are many hazards, and an individual bird may not make it through the migration. The migration of birds has been evolving over thousands of years and occurs all over the world.
Here are some of the world’s most spectacular long-distance migrants.
- Earlier this year, a 7-year-old female Arctic Tern broke the record for longest migration ever recorded: 59, 650 miles over her yearly migration from the coast of England to Antarctica and back. This is equivalent of flying around the Earth twice, with an extra 10,000 miles added to the trip. This trip was recorded by using geolocaters to track the bird’s position along their trip. Arctic Terns migrate through every ocean near almost every continent, and use global wind patterns. As geolocater technology improves, scientists estimate the this record will be broken.
- The record for the longest migration in a single flight is held by a Bar-tailed Godwit. This bird flew 9 days straight for 7, 145 miles from Alaska to New Zealand.
- Bar-headed Geese are the highest-flying migrants, who have been found flying 5 1/2 miles above sea level.
- The longest migration record used to be held by the Sooty Shearwater. They migrate around 40,000 miles round-trip from New Zealand to the Northern Pacific Ocean.
Other Fascinating Migration Facts:
- Before migrating, birds enter a state called hyperphagia. During hyperphagia, a bird’s hormones cause it to drastically increase its body weight in order to used stored fat as energy. Some birds may more than double their body weight before heading out to their new destinations.
- Many species of swifts, waterfowl, and hawks will mainly migrate during the day. Songbirds tend to migrate at night since the cool air help them fly more efficiently.
- While migrating, birds usually fly at speeds between 15-50 miles per hour. However, the Greater Snipe can fly at 60 miles per hour for up to 4,200 miles, making it the fastest flyer at long distances.
To learn more about bird migration, check out the following links:
Bird Migration Basics: The Basics of Bird Migration: How, Why, and Where by The Cornell Lab of Ornithology (www.allaboutbirds.org)
9 Awesome Facts About Bird Migration by Jhaneel Lockhart via the National Audubon Society (audubon.org)
If you want to learn more about the record-breaking Arctic Tern:
How a Tern Broke the Record for the Longest Known Migration by Sabrina Imbler for the National Audubon Society (article from June 2016)
Have you had any new migrants recently arrive in your area? Tell me about it in the comments below.