For millennia, herds, flocks, and schools have zigzagged the planet to find food, warmth, and a cozy place to procreate. Yet the natural instincts that tell animals where to zig and when to zag remain a total mystery to humans. How do butterflies that live for just weeks know to fly north—and when to stop? And what makes a bird start gorging on worms before it migrates?
These hive minds are coordinated by localized instincts. So it’s only fitting that animal migration now sits at the heart of the decentralized research economy, a burgeoning phenomenon driven by ordinary nature lovers, scientists, and millions of data entries. And it works like this:
Say you’ve hit the nature trails near your home in Texas. It’s early spring, and you spot a stunning black-and-tawny orange monarch butterfly up in a tree. Without missing a beat, you whip out your smartphone and snap a picture seconds before it flutters out of frame.
Next, you tap your Journey North app and upload the photo. Then you type in data about the current time, temperature, and location. Soon your butterfly pops up on a map that tracks the monarch’s 3,000-mile migration from Mexico to Canada, joining thousands of other entries.
Traditionally, the scope of scientific research has been restricted by time and distance, since researchers can’t be in thousands of places or track multiple species all at once. And even if they could put enough boots on the ground, finding the funding to do so is difficult. Citizen-driven research is changing this. Utilizing crowdsourced data, scientists can now make real-time observations on animal migration at a scale previously unthinkable.
“It’s really revolutionized the study of nature,” said Elizabeth Howard, founder and director of Journey North, an online education project that tracks the springtime migration of monarchs, birds, gray whales, and even frogs.
Howard started the project back in 1994, when email was just emerging. “Somebody had introduced me to this thing called the Internet,” she recalled.
Journey North was initially limited to classrooms but now includes the broader public. The site clocks 2,200 data entries a month from across North America and 2.4 million visitors a year, many through a free app for iPhone and Android users.
The crowdsourced data can’t tell us much about how or why species like monarch butterflies decide to flutter en masse across an entire continent each year. But the sightings do show how changes in temperature, climate, and other environmental factors like drought or destruction of habitat can impact their northern migration—and scientists can react accordingly.
Monarchs leave their home turf in central Mexico in the early spring, flying up through Texas and, eventually, to southern Canada. Within weeks, the butterflies lay their eggs on milkweed plants and die. The next generation carries the torch for a couple more weeks, before they too reproduce and drop off. It can take three or four generations of monarchs to complete the northern migration, which typically wraps up in the late summer. By contrast, it takes just one generation of monarchs to make the eight-month flight back down to Mexico.
This year, the Journey North data revealed that a chilly spring in Mexico and the southern United States had a dramatic impact on monarch migration. The cold snap meant milkweed plants were slow to sprout, and many first-generation monarchs died before they could lay eggs. Sightings in the northern US and Canada this summer have been rare. And this information arrived in real-time to the scientists.
Informal research is also providing clues on the impact of climate change. Allen Hurlbert, an assistant biology professor at the University of North Carolina, tapped 10 years’ worth of citizen birdwatching data for his 2012 study, the first to track birds from across the eastern US. He found that, on average, birds arrived at their destinations almost a day earlier for every Celsius degree of temperature increase. Such a change can negatively impact the health of bird populations.
His citizen sightings came from eBird, a science program run by the Cornell Lab of Ornithology and the US National Audubon Society. Hurlbert said he realized the database sightings “could be a potentially powerful source of information” when he saw how many people were contributing from across the country. Just last March, eBird participants logged more than 3.1 million bird observations at the peak of migration season.
Hurlbert believes it would be impossible to achieve the geographical scale that his study reached using traditional methods, such as attaching bands to individual birds. The professor plans to use eBird data for future studies on bird diversity across different terrains, like forested areas and urban sprawl.
Crowdsourced data, of course, comes with limitations. If you want to know whether birds that nest in western North Carolina face habitat degradation in their winter home in Brazil, for example, you’ll need to use more advanced technology like geolocators. However, these shortcomings continue to spur more ideas in the formal research community about what else to explore on migration and how to do so more effectively.
“Citizen science expands the eyes and ears,” said Howard of Journey North. And this helps us understand the flocks a touch better.