Buzz
Migration isn't just about wildebeests or zebras dashing across the African savannah. Scientists are still puzzled by phenomena that shouldn't migrate in an organized way—like shifting sand dunes and rolling moss balls.
The way humans interact with animal migrations often leads to unforeseen consequences. From eagles causing a Russian research project to go bankrupt with text messages to reindeer halting a famous TV show, here are ten strange migration facts.
10. Some Migrations Devour Bones
A prime example of this is the endangered European eel. Each year, these creatures embark on an extraordinary 3,000-mile (5,000-kilometer) trek across the Atlantic to their breeding grounds in the Sargasso Sea.
Throughout their months-long journey, European eels undergo a dramatic transformation from juveniles to adults. This process requires vast amounts of energy, so you might assume they’d feast on whatever they can find. However, these migrating eels refuse to eat at all.
Instead, their skeletons begin to break down, releasing essential minerals and nutrients to sustain them. Remarkably, by the time they reach the Sargasso Sea, these eels have lost over 50% of their skull mass and 65% of their spinal structure. They are one of the few species, alongside humans, that experience bone loss during their lifetimes.
9. The 70-Mile Radar Mystery
Meteorologists are accustomed to seeing flocks of birds appear as blips on their radar. But in 2017, an enormous smudge, the size of a city, appeared on the radar at the National Weather Service’s Boulder office in Colorado. Initially, the baffled scientists believed it was a massive bird migration heading into Denver, spanning an impressive 70 miles (110 kilometers).
To their surprise, the blip was caused by butterflies. A massive swarm of painted lady butterflies. This was an unusual event, as insects rarely form large enough groups or exhibit flight patterns coherent enough to trigger such a radar signal. As for why they made a detour through Denver, it’s because Colorado has worked hard to cultivate plants and flowers, making the state a perfect butterfly haven.
8. When TV Stars Rebel
Recently, Norway has been swept by a “slow TV” phenomenon, where viewers tune in to watch incredibly uneventful scenes unfold in real time, such as logs burning, people knitting, or even a full 7-day train journey from Bergen to Oslo.
In 2017, one particular show caught the public’s attention. More than a million viewers followed the annual migration of reindeer from the north to the island of Kvaløya. The broadcast was set to feature 168 hours of live footage, culminating with the reindeer’s dramatic swim across the Kvalsundet Strait.
At first, the reindeer followed their path, allowing the camera crew to track them with snowmobiles and drones. However, at one point in a remote location, where the crew had to use flashing mirrors to communicate, the reindeer suddenly stopped and refused to budge.
To prevent the 31-person crew from freezing in the harsh wilderness, the TV station decided to evacuate them, opting to film the reindeer’s swim later, though it was now expected to happen several days behind schedule.
7. Project Lights Out Philly
Each spring and fall, millions of migratory birds travel through Philadelphia. Unfortunately, most of these flights take place at night, when the artificial lights of the city disorient the birds, leading them to crash into windows and buildings. In 2020, it was reported that as many as 1,500 birds lost their lives within a three-block area in downtown Philadelphia on a single night.
This situation inspired the launch of 'Lights Out Philly' in 2021. The initiative urged Philadelphia's tallest skyscrapers to switch off their lights at night. While participation was voluntary, well-known buildings like Liberty Place, BNY Mellon Center, and the Comcast Towers, among others, agreed to go dark. This project not only saves countless birds during their migrations but also helps reduce carbon emissions and conserve energy in the city.
6. A Human Migrated with Swans
In 2016, a biologist named Sacha Dench embarked on an extraordinary journey alongside endangered Bewick's swans. These swans travel annually from their breeding grounds in Russia to England, covering 4,500 miles (7,240 kilometers). Dench aimed to document their flight and understand why so many of them fail to survive the long journey. Using a motorized paraglider, she began her migration with the birds from the remote Nenets region in the Arctic Circle.
The incredible winter adventure spanned three months, during which Dench traveled through ten European countries with the swans before finally arriving in the west of England.
Although Dench led the research, she was not alone in this endeavor. She was accompanied by a two-person support team in a microlight aircraft, a group of scientists on the ground, and hundreds of volunteers along the swans' migration route who provided valuable sightings and information about the birds.
Dench, who earned the fitting title 'the human swan,' confirmed that the decline in the rare bird species was primarily due to human activities. Specifically, illegal hunting and the transformation of wetlands into agricultural land were the major contributors to their downfall.
5. A Fascinating Tree Migration
This is not a case of trees uprooting and wandering like the Ents from 'The Lord of the Rings.' However, tree populations can migrate as younger saplings grow in new, more suitable areas, while the older trees die off. Although forest ecologists had predicted that climate change would push tree species in the eastern United States northward, the trees seemed to have different plans.
For reasons unknown, forests are now heading westward. Over the course of 30 years, nearly 75% of tree species from the eastern regions have shifted west at an astounding pace of 9.5 miles (15.4 kilometers) per decade.
Even experts are at a loss. Research indicates that climate change only explains a small portion of this strange phenomenon. Other potential factors, such as invasive pests, human land use, and conservation efforts, might play a role. But as of now, the true cause of the great American tree migration remains an unsolved mystery.
4. Turkey Halted an Ibis Migration
In the past, Northern bald ibises roamed freely across Europe, migrating without restriction. However, in 2016, Turkey decided to intervene and stop one particular flock from migrating. While it may sound harsh, Turkish conservationists took this action after realizing that many of the birds migrating from Turkey to Syria never came back.
It’s easy to understand why. The ongoing civil war in Syria likely claimed the lives of most of the missing ibises. Yet, this species is now critically endangered, with dwindling numbers. Immediate action was necessary to improve their chances of survival.
The flock resides at a breeding facility in Birecik, where they were once free to migrate. However, after several unsuccessful returns for four consecutive years, only 200 remain, and they have since been confined within the sanctuary. The center has stated that the flock may only be released if peace settles in the Middle East, although they plan to keep some adult birds permanently to ensure the group's continuity.
3. Conversations Among Sand Dunes
Historically, scientists believed that sand dunes were isolated, mobile entities that occasionally collided with one another and consumed each other. Yet, recent research has uncovered a new understanding. Migrating sand dunes communicate with each other to prevent such collisions.
In an experiment, a rotating water-filled channel kept two underwater dunes in continuous motion for hours. When dunes of similar size (or slightly varying sizes) interacted, the leading dune would accelerate, pushing the other dune to decelerate. Upon reaching the opposite side of the circular channel, the leader would slow down, and the following dune would speed up slightly. They eventually adjusted their speeds to maintain equal distances apart while traveling at the same pace.
Researchers are confident that these same principles are applicable to land-based dunes. However, regardless of whether the dunes are found on land or the ocean floor, the precise mechanism of how they communicate with one another remains a mystery.
2. The Mystery of the Moss Balls
In regions like Alaska and Iceland, there exist peculiar clumps of moss, roughly the size of a softball, known as “glacier mice.” While their name is strange, it’s not what makes them interesting. These moss balls have a unique ability: they migrate. And they do so in groups. The usual suspects—wind, sunlight, or sloped terrain—are ruled out as the causes of their movement.
Yet, these green spheres don’t wander aimlessly. No, studies reveal that all the moss balls in a colony move in perfect synchrony. Each ball travels about an inch (2.5 centimeters) per day, always in the same direction at the same pace. The colony can even adjust its speed and direction as a unit. Scientists are certain these aren’t random movements, but the exact force behind this migration remains unknown.
1. How Migrating Eagles Led to a Financial Crisis
Not too long ago, Russian researchers set out to track the migration patterns of steppe eagles. Their goal was to learn more about these endangered birds so that better protection measures could be implemented.
A group of ornithologists outfitted 13 eagles with GPS-GSM trackers. These devices utilized GPS satellites to monitor and log the birds' movements, storing this data in internal memory. When an eagle entered an area with mobile network coverage, the data was automatically transmitted to the research team via text message. Given the modest budget, each message normally cost just a few cents.
However, some eagles traveled so far into foreign territories that the roaming fees skyrocketed nearly 25 times. To make matters worse, a few eagles remained in areas without coverage for extended periods. When they finally neared a network tower, the research team was overwhelmed with a flood of text messages, racking up hundreds of dollars in costs each day. The study quickly ran out of funds.
When the public caught wind of the situation, it sparked a few chuckles. Yet, generous donors rallied to the cause, raising over $5,000 to cover the expenses and keep the project alive.
