New Issue: Science’s Impossible Questions. Read Now

Do Birds Really Migrate South for the Winter?

In a demonstration of the power of citizen science, millions of data points collected by laypeople helped generate stunning North American bird migration forecasts for more than 300 species

Join Our Community of Science Lovers!


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


As common wisdom has it, bird flocks in the Northern Hemisphere move from northerly locales in the summer to southerly ones in the winter. For many species, such as the White-throated Sparrow, this notion holds basically true. A closer look at the details of this bird’s movements, however, is much more intriguing, as you can see in this 25-second animation created by eBird, a citizen science project organized by the Cornell Lab of Ornithology and the National Audubon Society. For birders, the information offers a wealth of new insights. Ornithologists, too, can use such data to learn more about migratory behavior, the impact of climate on migration and variables affecting population sizes. In addition, such animations can be useful for conservation biologists and scientists in other fields seeking indicators of climate change as well as for studies of biodiversity shifts and other markers of evolution.

As you will see in the clip, these sparrows spend nearly all their time from June through September either in Canada or in northern areas of New England, New York, Wisconsin and Minnesota, along with Michigan’s Upper Peninsula. That's useful information at a simple level for fanciers like me. I won't go looking for any White-throated Sparrows where I live, in New York City, in the warm months. And strangely, these birds never foray far into Florida, my winter stomping grounds, although they can be found in large numbers at that time in eastern Texas and throughout Louisiana, Mississippi, Alabama and Georgia.

The animation is mesmerizing, and eBird has created such graphics for more than 300 bird species. Nearly as amazing, amateur scientists (maybe some of you reading this story) played a large part in creating them. Thousands of volunteers with the eBird project have been collecting and sharing up to millions of bird observations each month for the past 10 years. Without such armies of laypeople as observers, such data sets would otherwise be out of reach or impossible to obtain. (For more about this burgeoning field and its impact on science, read Hillary Rosner's feature, “Data on Wings,” in the February issue of Scientific American.) Those eBird data have been combined with remote-sensed information on climate, habitat, night flight calls and other variables to generate spatiotemporal exploratory models (aka migration forecasts) as well as more static “birdcasts” (weekly migration forecasts for birders focusing on seasonal species and the impact of weather), estimates of how far birds fly, and myriad other insights.

Journalist Robin Lloyd, a contributing editor at Scientific American, is president of the Council for the Advancement of Science Writing's board of directors. Follow Robin Lloyd on Twitter.

More by Robin Lloyd
Scientific American Magazine Vol 308 Issue 2This article was published with the title “Do Birds Really Migrate South for the Winter?” in Scientific American Magazine Vol. 308 No. 2 ()
doi:10.1038/scientificamerican022013-4bppwrPVktGQHCI0ODtSgB

Subscribe to Support Independent Journalism

Great science journalism requires human expertise, time, effort and creativity. And it costs money. That’s why I and the journalists here at Scientific American hope you’ll join our community.

When you subscribe, you are supporting staff and freelance journalists who are passionate about telling science stories that are true, important and compelling. Our editors and reporters are often experts in their fields, which means they understand the nuances of big discoveries and can untangle the breakthroughs from the hype. With a subscription, you are also supporting rigorous fact-checking to ensure the words we publish are precise and accurate. And you’re supporting original illustrations, graphics and photos that bring you closer to an advanced laboratory, an ice sheet in Antarctica or a space mission in orbit. You’re helping us craft other types of high-quality journalism as well: Our newsletters are carefully written, edited and curated by staffers you have or will come to know and love. Our Science Quickly podcast is based on original reporting, collaboration with editors and scientists and exacting production.

Subscriptions keep this engine running so we can continue to deliver thoughtful, rigorous and independent science journalism to you. In an era of viral misinformation, this work is crucial. If you value what we do, I hope you’ll consider joining us as a subscriber

Thank you,

Jeanna Bryner, Editor in Chief, Scientific American

Subscribe