May 1, 2019

BirdCast: Birding in The Age of Technology

Posted by: Cohen Carpenter

BirdCast: Birding in The Age of Technology


For millions of years birds have transited the globe in search of resources, climate, and other ideal conditions to fulfill their life histories. As of yet, they are not giving us humans a verbal “heads-up, here we come” to let us know when, where, and exactly how many of them are going to move on a given night. Science and big data, however, are providing researchers and birders the opportunity to answer these questions with increasing accuracy.

We are in the midst of Spring Birding here on Little St. Simons Island, and we’re out every morning and afternoon listening, looking, ooh-ing, and ahh-ing. It’s the time of year when many species are moving from southerly wintering habitat to breeding grounds for the summer. Some passing through, some setting up to raise their young right here. We chose this time-frame for the event based on years of years of observation, knowing when we are likely to observe the greatest density and diversity. Since last year though, we have been able to predict bird movement at an even finer scale. So can you! BirdCast, a bird migration modeling and visualization technology created by the Cornell Lab of Ornithology and collaborators allows users to see details of the bird migration expected on a given night before retiring and, when they roll out of bed, the migration that occurred (most bird migration occurs throughout the night, when temperatures are cooler and darkness provides cover from some avian predators, with many species taking off within the hour after sunset).

How does it work? Weather radars.

The same doppler radar that informs you if you need an umbrella every morning also lets you know if you need your binoculars. Establishing correlations between weather and bird movement from 23 years of data from doppler radar, Van Doren & Horton, 2018, showed that those details like where, when, and how many, can be accurately predicted. Their models for doing so are now incorporated online into easy-to-read maps that use warmer coloration (red) to depict high-intensity expected migration and cooler coloration (blue) for low-intensity. Expected migration is based on weather conditions expected 3 hours after local sunset. See what tonight looks like in your area.

*^BirdCast visual showing expected migration for the night of May 2nd into the morning of May 3rd. Warmer coloration depicts high density migration expected, and cooler colors predict low density expected migration.


Using detections from the US weather surveillance radar network, BirdCast also provides live migration maps, showing real-time bird migration. This data is collected from sunset to sunrise, local time, and migration density is depicted using a color spectrum from black to white, with white being the highest density (50 thousand birds passing through a 1km transect per hour). Orange areas show the direction of bird movement, green dots show radar locations, and red dots show radar locations with no data available. Press the play button and watch any night’s migration unfold in 10-minute increments, dating back to March 20, 2018. See what last night looked like in your area.


*^Live Migration Map showing the bird movement on the night of May 2nd. Light indicates high migration density and dark indicates low density. Arrows indicate direction of travel. Green dots indicate locations of radars providing data. On the website, one can press "play" to see the migration as it occurred through the night in 10-minute increments.


For birders, these tools are incredible resources to have in our pockets for planning our next outing, but they have much broader implications for the science of ornithology and conservation efforts. This new data source will provide insight into bird migration as it relates to things like climate change, changes in a species population sizes, and human population data. This data can also be used to make decisions regarding the lighting of tall buildings at night, a major threat to bird populations resulting in hundreds of millions of bird deaths each year.

Kudos to the BirdCast team and all collaborating efforts for this amazing work!

What a time to be a birder.




  • Van Doren, B, M, & Horton, K, G, 2018. A continental system for forecasting bird migration. Science: Vol.              361, Issue 6407, pp. 1115-1118.
  • National Audubon Society, 2018Building Collisions Kill Hundreds of Millions of Birds per Year. Audubon            Press Room: January 30, 2018.

Return to Blog Home