About 40 percent of the world's birds migrate in some fashion, whether it's a short flight to a warmer locale or a long and arduous trek. Like other animals that undertake migrations, birds travel to find places with more resources or when breeding requires it. Plenty of variables play a role in how and when birds decide to migrate, including the climate and the availability of food and other resources. Above all, it's a special balance for each species. As Cornell Lab of Ornithology explains, even hummingbirds can survive chilly temperatures provided there's enough food to go around.
Whether it's for their migratory treks - some of which are incredibly long - to their status as endangered species, these birds are special high-flyers.
1. Bar-tailed godwit (Limosa lapponica)
Measuring at most some 16 inches (41 centimeters), the bar-tailed godwit (Limosa lapponica) is not a large bird, but this species under takes a very long flight. In fact, the migration of the bar-tailed godwit is the longest non-stop migration of any bird on the planet. A 2007 study published in Proceedings of Royal Society B tracked birds migrating from New Zealand to China's Yellow Sea, a distance of around 5,950 miles (9,575 kilometers) at its shortest distance. The birds, however, flew more 6,800 miles over the course of nine days without stopping, following a longer path. At least one of the birds then flew from China to Alaska; that bird then flew from Alaska back to New Zealand.
2. Whooping crane (Grus americana)
This endangered bird is the tallest in North America, standing nearly 5 feet tall (1.5 meters). Though you might expect a taller bird like this to make a longer migration, the wild whooping crane population doesn't make a particularly long trek, but it is an important one. This population summers in Canada's Wood Buffalo National Park and travels south to Texas' Aransas National Wildlife Refuge for the winters, a journey of some 3,000 miles (4,800 kilometers).
Multiple reintroduction programs have attempted to establish populations in the continental U.S., with mixed success. These populations have at times been guided in their migrations by humans flying ultralight aircraft, but federal regulations have hampered these efforts. Now, a number of whooping crane populations spread throughout Texas, Florida Louisiana and other states are considered non-migratory, staying in these locales year-round.
3. Calliope hummingbird (Selasphorus calliope)
From the biggest to the smallest: The calliope humming bird is the smallest breeding bird in Canada and the U.S. at only about 3 inches (7 centimeters) long. These tiny hummingbirds make an impressive journey for their size, and that's not even for migrations. These birds breed high up, sometimes 4,000 and 11,000 feet (1,219 and 3,352 meters) high, often near mountains, while their nests are often about 40 feet from the ground.
According to the Cornell Lab of Ornithology, these hummingbirds travel some 5,000 miles (8,046 kilometers) round-trip every year, leaving central and southern British Columbia in the later summer to make their way south along the Pacific Coast and the American West to reach Mexico, where the entire population - an estimated 4.5 million - spends the winter.
4. Orange-bellied parrot (Neophema chrysogaster)
Only three parrot species migrate, but that number may soon become two. The orange-bellied parrot is a critically endangered migratory bird, with the International Union for Conservation of Nature (IUCN) estimating that there were just 14 birds living in the wild as of February 2017. Efforts are underway to save the species by breeding it in captivity.
These parrots don't travel far for their migration. They breed in South West Tasmania during the summer and fly over the Bass Strait to Australia, often settling in Victoria or South Australia in the winter, a distance of roughly 600 miles (966 kilometers).
5. Eurasian wryneck (Jynx torquilla)
The Eurasian wryneck - it gets half of its name from the ability to turn its head 180 degrees - is a woodpecker, albeit one with a shorter bill than other woodpeckers. As a result, the wryneck often reuses the holes of true woodpeckers for nesting instead of making its own.
The Eurasian wryneck, as the other half of its name suggests, has a large range, stretching across Europe and Central Asia. It's also the only Old World woodpecker that undertakes a long-distance migration. The European population will winter south of the Sahara, across a band of African countries from Sierra Leone to Ethiopia, a flight of almost 4,000 miles (6,437 kilometers), depending on the bird's starting point and destination. The population in Central Asia migrates south to India, Thailand and even southern Japan. These flights can be as long as 3,000 miles, depending on the bird's points of departure and landing.
6. Northern harrier (Circus hudsonius)
According to the Audubon Society's field guide, North America is home to only one species of harrier, and that's the northern harrier. This member of the hawk family has a large range that stretches from Alaska and some of the northernmost parts of Canada to the southern United States. While those populations in the southern U.S. tend to stay put - no reason to migrate when you're already in pretty consistent temperatures - the harriers that reside further north will fly as far as Venezuela and Colombia to winter, a trek of some 5,600 miles (9,012 kilometers) depending on where they begin their journey.
7. Sooty shearwater (Ardenna grisea)
This incredibly common seabird, the IUCN estimates a global population of around 20 million individuals, has a most uncommon migration length. According to a 2006 study published in the journal PNAS, or Proceedings of the National Academy of Sciences of the United States of America, the birds fly almost 40,000 miles (64,000 kilometers) over the course of 200 days.
The sooty shearwaters in the study left New Zealand during autumn in the Southern Hemisphere and flew to the North Pacific in the Northern Hemisphere. Birds would settle in Japan, the Aleutian Islands or California. On the way back to New Zealand, some of the birds stopped by Chile.
8. Northern wheatear (Oenanthe oenanthe)
The northern wheatear, like a few of the birds on this list, has a sizable range. They breed all across Eurasia and along both of North America's northern coasts. When it comes time to fly south for winter, the northern wheatear, regardless of their original starting point, heads for sub-Sahara Africa. In many cases, this flight involves traveling over oceans and ice, not exactly environments you expect to see songbirds.
These birds all take different routes to reach their destinations. "From the eastern arctic of Canada, wheatears traveled through Greenland to northwestern Europe before flying south to western Africa," the Cornell Lab of Ornithology writes. "Their western Arctic compatriots went the other way around the globe: they flew westward to Siberia and then diagonally across Asia to wind up in eastern Africa.
The birds that start from Alaska make a 9,320-mile (15,000 kilometer) trek just to get to Africa. When the wintering season is over, they do it all over again to get back.
9. Baer's pochard (Aythya baeri)
Baer's pochard breeds mostly in eastern Russia and northwestern China, though there are reports of them breeding in Mongolia and North Korea as well. Once winter settles in these regions, these ducks head south, flocking to eastern and southern China, northeastern India, Thailand and Myanmar.
These aren't particularly long journeys, but they are journeys that may stop soon. Baer's pochard is a critically endangered bird, with an estimated population between 150 and 700 mature individuals. The birds seem most vulnerable during winter, and that's because of hunters. Additionally, the loss of wetlands in their breeding grounds has also contributed to their decline.
10. Snowy owl (Bubo scandiacus)
The migratory habits of snowy owls are a bit of a mystery to us. They fly south when winter arrives in their northern Canadian and Arctic habitats, but sometimes they go far south - like, really far south. During the 2013-2014 migration, snowy owls were reported in Massachusetts, Virginia, Arkansas, Florida and even Bermuda. In 2012, one was even spotted in Hawaii, presumably because it stowed away on a ship. Tagged birds demonstrate that despite their southern exposure, they still make their way back to the Arctic Circle.
Snowy owls are more nomadic than migratory, leaving their traditional stomping grounds to hunt for food, but a lack of a food doesn't always seem to be the reason they push so far south. The owls spotted during the 2013-2014 irruption, a term used for unusual bird migrations, were all reported as being healthy. In short, we know they do this, but we don't know why.
11. Arctic tern (Sterna paradisaea)
If you're looking for a truly long flight, look no further than the migration of the Arctic tern. These small birds live in the Arctic Circle, but populations can be found in Massachusetts and England as well. The species has a convoluted and long trek to make it to breeding grounds along the Antarctic coast. Yes, that's right, the Arctic tern flies from the Arctic to the Antarctic every year. Round trip, the Arctic tern's flight covers 59,650 miles (95,997 kilometers), more than any other bird on the planet. (To put this flight in perspective, the Earth's circumference is only 24,901 miles.)
Top image: Birds fly in a group during sunset near the German nature reserve Alte Leine. Credit: Wernersen04/Wikimedia Commons.
Top image: Birds fly in a group during sunset near the German nature reserve Alte Leine. Credit: Wernersen04/Wikimedia Commons.
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