Monarch Migration

Most surprising migration

You know those beautiful orange, black, and white butterflies — the monarchs? They’re one of the most famous and recognizable species. (They’re unfortunately an endangered species now, so if you see one, that’s a great sign!) They’re also incredible, flying from Canada and the northern United States each year all the way to Mexico and California, making a journey of up to 3,000 miles in several months.

Despite their small size, monarchs use a sophisticated navigation “system” to get where they need to go. To know which direction to fly, their bodies rely on the position of the sun, magnetic fields, and other environmental cues, though scientists aren’t entirely sure how they do it. It’s an especially amazing journey considering that no butterfly does the round-trip journey more than once (they just don’t live that long).

Monarchs are the only butterflies known to make a two-way migration like birds. They make the trip because they cannot survive the cold winters of northern climates. When they go back up north, the females lay eggs and then die. And the next generation somehow knows to make the journey south again.

Distance:

About 3,000 miles one way

Challenges:

Predators, weather, habitat loss, pesticides

Wildebeest Wanderings

Most Dangerous Migration and Largest Overland Migration in the World

You may not be familiar with the wildebeest, aka the gnu. They’re “ungulates,” uhn-gew-lahts, or hoofed mammals, and members of the antelope family. Every year, over a million wildebeests make the dangerous journey from Tanzania’s Serengeti to Kenya’s Masai Mara (and back again), following the seasonal rains and searching for greener pastures (that is, food). Along the way, they must cross raging, crocodile-infested rivers (yikes!) and avoid other predators like lions and hyenas (also yikes!).

People travel to the region just to witness this amazing migration, which is the largest (in terms of numbers) land migration of any mammal in the world. Seeing one-and-a-half to two million animals of this size traveling in a massive herd is supposedly truly spectacular. They spend the wet season (January to April) in the Serengeti and the dry season in the Masai Mara (July to October). And in between, they run, traveling some 500 miles in each direction. Scientists still don’t know how wildebeests know where to go on their journeys, but they think they are able to sense and follow the weather — and, of course, the growth of new grass. Some 250,000 wildebeests die during the migration, killed by predators or brought down by thirst and hunger before reaching greener pastures.

Distance:

Around 500 miles one way

Challenges:

River crossings, predators, thirst, and hunger

Tern Travel

Longest Migration

Artic terns are seabirds that spend their winters in Antarctica (when it’s actually summer there) and their summers in the Arctic (when it’s summer there, too). It’s confusing to think about, but that means the Arctic tern sees more daylight than any other creature on the planet.

To make such a trip, the birds must fly some 22,000 miles in each direction, riding the winds and thermal air currents (a stream of air rising from the Earth’s surface that is created by temperature differences between the air on the ground and the air higher up). These amazing birds can also fly for days without stopping, covering as much as 6,000 miles without taking a break.  That’s basically the length of the trip from Eretz Yisrael to the East Coast of the United States! Good thing these birds are excellent gliders so they don’t have to flap the whole time. Not surprisingly, terns are the record-holders for longest migration journey of any known animal in the world.

Terns can live for over 30 years, and they make that roundtrip journey during every single one of them, which means that they have amazing endurance. To avoid storms, strong winds, and certain predators, they fly high above the sea. If they do stop along the way, they eat small fish and squid to fuel their journeys. Terns have something called “biomagnetite” (by-oh-mahg-nuh-tight) in their brains. Researchers think this compound makes the birds sensitive to the Earth’s magnetic fields, which helps them navigate. They also follow the sunlight.

Distance:

About 22,000 miles one way

Challenges:

Storms, strong winds, birds of prey

Hummingbirds Take a Hike

Solitary Migration

Ruby-throated hummingbirds are one of the tiniest birds in the world, but that doesn’t stop them from making a major annual migration. They travel as far as from Canada to Panama on a journey that can span 2,000 miles. The tiny birds determine when to begin their trek based on the angle of the sun. They migrate in search of food and better weather conditions.

In the weeks leading up to their great journeys, they eat twice their weight in food, storing up fat for the trip. They really need all that energy; after all, they can beat their wings 50-70 times each second, with their hearts beating up to 1,260 times per minute.

Unlike most other birds that travel in large flocks, ruby-throated hummingbirds mostly migrate alone. Even juvenile birds on their first migration trip fly solo, with no guidance from any other birds. They’re just born with the instinct to head south. Research has shown that the same hummingbird can appear in the same location on the same day from one year to the next.

Most songbirds and many other species travel mostly at night, but hummingbirds migrate mainly by day, stopping to eat along the way. Hummingbirds can only reach speeds of up to 35 miles per hour, which isn’t much compared to other, larger birds (like the peregrine falcon, which can fly at 200 mph!), but is still pretty impressive for such a tiny creature. One part of their journey takes them over the waters of the Gulf of Mexico; during this leg of their trip, they’ll fly nonstop over 500 miles to reach the shore, a flight that usually takes 18-22 hours.

Distance:

Up to 2000 miles one way

Challenges:

Extreme weather

The Pfeilstorch

Back in 1822, in the German village of Klutz (yes, that’s really its name), a hunter shot a white stork out of the sky. When it came down, the hunter discovered the stork had already been shot by someone else. The poor bird had a 30-inch spear lodged in its neck (this bird did not have good luck). Not only that, but the spear was also clearly African in origin. That means the bird flew from Africa to Germany with a spear as long as six soda cans lodged in its neck. Ow!

Though the bird did not have a happy ending, its story helped people learn about migration. Until then, people had observed some kinds of birds appearing and disappearing at certain times of the year, but they had no idea where they went in between. The Pfeilstorch (arrow stork), as it became known, provided solid proof that storks travel as far as Africa on their off-seasons. The Pfeilstorch was stuffed and can still be seen today at the University of Rostock’s zoological collection (you know, if you’re in Germany or whatever).

Gray Whale Wayfaring

Longest Migration of Any Mammal

Several species of whales make incredibly long migrations each year, but gray whales are the record holders for the longest migration of any mammal on Earth. They travel 10,000-14,000 miles each year, journeying from the Arctic to Baja, Mexico, and back again. While they’re known to navigate by sight, they also use magnetism and the songs of other whales to find their way.

These gentle giants weigh more than 36 tons and reach 50 feet in length (a drop longer than a semitrailer). And they travel at only around five miles per hour (which is still faster than the average human walking speed). But that doesn’t stop them from going great distances in search of abundant food sources and a safe place to have their calves.

They cover around 75 miles per day on their journey, which typically takes two to three months on the southward leg and a bit longer on the northward one. During their journey, they face mostly human-related dangers, including getting hit by ships and boats, getting entangled in fishing nets, and getting sick from pollution.

Distance:

Up to 7,000 miles one way

Challenges:

People

Reindeer Ramblings

Migrations that move like one body, longest overland migration

Reindeer, or caribou, live in the northern parts of Europe, North America, Asia, and Greenland, and each year they take a journey that’s widely considered to be one of the world’s greatest animal migrations. We’ll call them caribou from here on, because although reindeer are the same, reindeer are typically domesticated (living with people), while caribou are wild.

Caribou voyage from the tundra (a large, barren region with no trees) to the forests, in search of food and a safe place to have their babies. And those babies have to be prepared to be up and running the day they’re born!

The migrating caribou herds can number in the hundreds of thousands, and the herds move in what appears like a carefully synchronized “dance.” People who’ve witnessed it say that the thousands of caribou together actually appear like one giant organism, moving in perfect time with each other. This is essential to their survival; when they see a wolf or bear, for instance, they will twist and turn as a group to give them the best chances of outwitting or outrunning the predator — and then they can suddenly break up, running in all directions, causing further confusion.

In addition to facing predators like bears and wolves on their journey, the caribou have to cross rivers, mountains, and swamps, face harsh weather, and more. And they face many human obstacles, like roadways, construction, and other infrastructure that can get in their way. They can travel up to 50 miles a day, navigating with a built-in “compass,” similar to birds, even traveling to places they’ve never been before.

Distance:

Around 750 miles one way

Challenges:

Predators, human infrastructure

Turtle Trips

Amazingly Specific Migrations

Green sea turtles, the largest species of hard-shell sea turtle, embark on a migration that’s amazing not only for the distance traveled (up to 1,200 miles each way, with some on record going 1,600 miles) but also for its specificity. Green sea turtles return to the beaches where they were born to lay their own eggs.

Scientists believe the turtles use the Earth’s magnetic field like a compass. Each part of the coastline has its own unique magnetic signature. The turtles somehow remember that “signature” and later use it to find their way “home.”

Though green sea turtles spend most of their lives in the water, when it comes time to lay their eggs, they’ll find their way back to the beaches where they hatched out of eggs themselves. They use their flippers to dig a pit in the sand where they lay their eggs, which they then cover with sand before returning to the water. When babies hatch, they journey out to the ocean and then come back as adults to lay their own eggs on the same beach where they were born, repeating the journey of their mothers.

Green sea turtles also migrate to find food. The main challenges green sea turtles face during their migration are caused by people, who hunt them illegally, accidentally catch them in fishing nets, unintentionally kill them with pollution, destroy their nesting grounds with construction, and so on.

Distance:

1,200 miles one way

Challenges:

People

Whether we’re marveling at the grace of a monarch butterfly or the power of a wildebeest herd, we can’t help but be awed by the amazing feats of animal migration. So the next time you see a flock of birds overheard or a butterfly fluttering by, think about the incredible journeys that brought them to your doorstep. How can we not appreciate the amazing creations Hashem put in our world?

(Originally featured in Mishpacha Jr., Issue 957)