The blackburnian warbler is a tiny songbird that weighs about the same as four pennies. Some of them are yellow, streaked with black and white. Others brandish a splash of tangerine across their face and throat. These birds typically spend their summers in the northeast US and some parts of Canada. In the winter, they fly down to South America, where they spend time in coffee plantations across Colombia, eating insect pests like spiders, aphids, ants, flies, beetles, and mosquitos alongside other migrating birds like tanagers and orioles. 

“Migratory birds are really important,” says Jill Deppe, senior director of the migratory bird initiative at the National Audubon Society. “In a single year, a single bird can eat enough insect pests to save a farmer 25 pounds of coffee per acre.” 

Many birds make incredible trips every year. The Arctic tern completes globe-trotting flights from one pole to another, clocking in 49,700 miles in a year; and the bar-tailed godwit holds the record for the longest non-stop flight at 7,000 miles.

It’s hard for most people to imagine what happens to birds after they leave backyards and city parks—where they go and what they get up to. But migratory birds serve as critical links between ecosystems half a world away. And losing them would have a devastating ripple effect

That’s why Deppe, Audubon, and other researchers, institutions, and technology vendors, built an interactive map, called the Bird Migration Explorer, helping non-scientist bird enthusiasts see a snapshot of the journeys these birds undertake, and understand their impact. It came online this week and is available in English and Spanish. Visit it here.

Birds photo
The explorer allows you to track bird migrations like you would track flights out of major airports. National Audubon Society

“What we have done with the Bird Migration Explorer is that we have brought all of the science together to show people how they are connected by migratory birds across the hemisphere, and show them the local actions they can take where they live have a hemispheric impact,” says Deppe. It also points out the importance of international collaboration in conservation efforts.

Synthesizing all the information they collected into an accessible, user-friendly tool was no easy task. Here’s how they did it. 

“We have lots of different types of data. Some are very precise, some are very coarse,” Deppe says. That data spans general range maps that appear in birding field guides, to genetics information, to connectivity, to seasonal abundance that birders have recorded in Cornell Lab of Ornithology’s ebird database to data from over 500 migration studies and more than 280 institutions. 

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“We have been working on this for four years, thinking through how to get different types of data into a single map that tells a story that makes the science understandable,” Deppe says. “We couldn’t do everything in one map. So you’ll see on the explorer we have a series of maps.”

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There are over 400 bird species with their own profiles. National Audubon Society

One map is focused on the movement of the birds. It integrates tracking data and overlays it on the abundance data, which shows how frequently a species of bird is spotted in an area. 

The second map is a map of the connections. It uses some tracking data and data on the locations of banded birds. “If you put a band on a bird and someone finds it somewhere else, you have a connection between those two points,” Deppe explains. This connection map also considers the genetic composition of the bird species. “It’s almost like, but for birds,” she says. “If you catch a bird you can look at its genetics and trace it back to a different location and atmosphere.” 

The third map shows where and when birds face the most conservation challenges—from climate change to light pollution to industry and agriculture practices.

To start, there are 458 species documented in the explorer. For 184 of them, the team gathered tracking data for the pathways of 9,000 individuals. 

Consider the bobolink, a common grassland species. The map shows the location of the bird at various times in the year. Select species are tracked with multiple technologies. For the bobolink, a few individual birds were tracked with a light-level geolocator device, but some were tracked through tags and an array of automated radio telemetry towers. The combination of the two allows researchers to see what specific areas are critical for the birds, and how they get there. 

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“We’re starting to use this new technology to reveal the bigger picture. And we can look at these birds across the year. This tells us where the important places are for migratory birds,” Deppe says. “Each type of data is a unique piece of the puzzle.” 

This kind of all-in-one-place information can also be used to influence local policy decisions and bring awareness to personal actions, argues Deppe. If you know that many migratory birds are passing through a large metropolitan area that you live in, like New York City, you might be more motivated to put out a potter of native plants on your balcony or argue for the preservation of a local green space park or ask managers of tall buildings to turn off lights at night during peak migration season.  

And because conservation decisions should be made based on the best available science, the team is focused on keeping the data on the site as up-to-date as possible. “People are publishing studies, tagging birds every day. There’s new information coming out,” Deppe notes. To this end, they’ll continuously reach out to data sources, and they aim to update the explorer every couple of months, so the visualizations pull in new information. Some information, like the ebird observations on abundance, will likely be updated on an annual basis, whereas tracking data might be updated more frequently. For scientists interested in working with specific data presented on the site, there’s a data provider panel on the lower right corner that shows the citations for every map.

Above all, ecologically, migratory birds are good indicators of the state of the environment. They’re like the canaries in a coal mine for climate change. “We have lost a lot of birds,” says Deppe. But we can reverse the damage. “We’ve seen some groups like waterfowls that weren’t doing well and we helped turn it around—it’s the one species that has been increasing in the last few years.”