Winged wonders and maiden flights

Monarch butterflies undertake one of the longest migrations of any insect. Every fall, millions of them leave their summer breeding grounds in the northeastern U.S. and southeastern Canada to travel more than 3,000 miles south to the mountains of central Mexico. Here they will spend the winter months before beginning the journey north again in February or March. Monarchs are the only butterflies known to make a two-way migration like some bird species―but, unlike birds, the monarchs’ journey north will span three to four generations.

From December to January every year, scientists estimate the number of monarch butterflies that have made the annual migration to Mexico by calculating the area the butterflies cover when millions gather in the mixed pine and fir forests in the mountains of central Mexico. But habitat loss and climate change threaten to disrupt the monarch butterflies’ migration pattern, as well as the species’ very existence. In 2022, the International Union for the Conservation of Nature (IUCN) added the migratory monarch butterfly to its Red List of Threatened Species, listing the embattled butterfly as Endangered.

Every year between October and December, an estimated eight to ten million straw-colored fruit bats arrive in Zambia’s Kasanka National Park after a journey of thousands of miles that scientists believe is the world’s largest migration of any mammal species. Once in the park, the enormous colony departs en masse every evening at sunset from their swampland tree roosts in search of fruit and berries, returning to roost again by dawn. The bats play an important role dispersing seeds each night, which helps new trees to grow. Like the migrating monarch butterflies, straw-colored fruit bats are threatened by habitat loss driven in large part by deforestation, though legal efforts are being made to curb deforestation along the park’s borders.

Adélie penguins migrate around 8,000 miles every year, skirting the edges of the sea ice as it expands and contracts with the seasons to ensure they are never without food, light―and a safe place to rest. Penguin parents’ journeys in search of food can be long and sometimes treacherous for the waiting chicks: In any given year, as many as 80 percent of Adélie penguin chicks may never reach their first birthday due to predation by seabirds or desertion by parents. With a life span ranging from 11 to 20 years, these penguins are long-lived, and an already large and increasing population means the Adélie penguin is listed as a species of Least Concern by the IUCN.

The globe skimmer is the most widespread of dragonfly species, and is found on every continent except Antarctica. This dragonfly is believed to make the longest nonstop migratory flight of any animal (adjusting for size). The globe skimmer travels an estimated 11,200 miles every year on an intergenerational journey that crosses the Indian Ocean from India to East Africa in the fall, with the next generation embarking on the return trip in spring. Scientists believe these small dragonflies employ a mix of flapping and gliding techniques, taking advantage of wind patterns to complete their journeys, which include a nonstop flight of 2,000 miles across open ocean each way.   

In the speed over distance stakes, great snipes win the race. Each year, the birds leave summer breeding grounds in Sweden and fly more than 4,000 miles to sub-Saharan Africa. Great snipes have been recorded flying at up to 60 miles per hour, and though most of the birds fly at a height of around 19,000 feet, one great snipe reached a record-breaking 28,500 feet. Little surprise, then, that they lose half of their body weight during the journey.    

When it comes to sheer distance covered in a single flight, the bar-tailed godwit is unmatched. Migrating from the Northern to Southern Hemisphere every fall―and back again in the spring―these shorebirds regularly cover upward of 6,000 miles in a single flight. In fact, in November 2022, a team of scientists recorded the longest known nonstop bird migration when they confirmed that a four-month-old juvenile bar-tailed godwit flew an astonishing 8,425 miles in 11 days, leaving its breeding grounds in Alaska in October to follow the sun―and summer―to Tasmania, Australia.

The arctic tern is the undisputed champion when it comes to long-haul flying. Weighing in at a diminutive 3.2 to 4.2 ounces (90 to 120 grams), these endurance specialists are estimated to cover 25,000 miles each year, flying from pole to pole to follow the summer season. Researchers now suspect they fly much farther—an arctic tern was recently recorded to have covered a staggering 59,650 miles in a year—the equivalent of circumnavigating the globe twice with an additional nearly 10,000 miles in change. 

Human-driven climate change is impacting animal migrations everywhere. Reducing carbon emissions from aviation is crucial if we’re to achieve the United Nations’ call for net-zero carbon emissions by 2050. One solution is electric flight—and commercially viable electric flight is now a reality. Eviation has developed an aircraft with around four tons of battery built into its fuselage. The aircraft made its successful maiden flight in September 2022, and is expected to be able to cover 250 nautical miles in a single flight. 

As part of its commitment to reaching net zero emissions by 2050, logistics company DHL has ordered 12 Eviation Alice cargo planes capable of loads up to 2,600 pounds. The planes, expected to be delivered in 2027, will be used on feeder routes, which connect to routes that carry heavier traffic. The company already generates 86 percent of its electricity from renewable sources, and is electrifying its ground fleet of vehicles, as well as using sustainable aviation biofuels, building carbon neutral warehouses, and training more than 70,000 of its staff to become certified GoGreen specialists. 

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