In the Spring of 2017, after 400 birds crashed to their deaths in a single night by flying into a brightly lit high-rise in Galveston, Texas, Houston 爆料公社 and local partners quickly worked with the building owners to help shut off the lights for the remainder of migration season. By doing so, they surely spared the lives of many other migratory birds that are attracted to or confused by lights as they make their annual journeys north or south.
While this was a huge win, Houston 爆料公社 realized it could make an even bigger difference, says Richard Gibbons, conservation director of Houston 爆料公社. This past spring, the chapter to let homeowners and businesses know which nights would be most active for migrating birds. These alerts were based on a recently released tool from the Cornell Lab of Ornithology called , which uses observation data and doppler weather radar to predict and track bird migrations. 鈥淭his is not just me prognosticating, looking at tea leaves or something,鈥 Gibbons says. 鈥淭his is based on science.鈥
Upon its release, BirdCast's popularity with birders itching to see migrants was immediate, but as Houston 爆料公社 showed, it also has huge potential value as a conservation tool. This week, new research looking at the modeling used to predict migration patterns this spring, further supports this idea. Not only are the forecasts highly accurate, the researchers found, but BirdCast is able to reliably predict migration timing up to three days in advance.
The images from BirdCast should look familiar to anyone who鈥檚 watched a TV weather report. Fed by precipitation data, generated every few minutes from 143 towers country-wide, the instruments also pick up moisture-laden animals passing through the sky. 鈥淏irds are like large raindrops in the atmosphere,鈥 says , an ornithologist from the University of Oxford who works on the forecasts. These traces of wildlife are a nuisance to meteorologists, who have to edit them out of standard weather data, but a boon to anyone searching for birds.
Using new machine-learning techniques, Van Doren and , who studies bird migrations at Cornell, trained an algorithm to forecast migration activity using 23 years of radar data and bird observations. The findings show that migration largely happens in a few big bursts: Half of all migrants move on roughly eight nights of the entire season, Horton says. For spring migrations, their model closely predicts the intensity of migration actually observed, explaining about 70 percent of bird activity three days in advance. (The percentage jumps to 80 percent only a day out.)
In spring, a warmer temperature is the biggest predictor of which nights will see this flurry of activity. Different factors play into birds鈥 decisions to move in the fall, but the majority still take to the sky on fewer than 10 nights. Fall migration could be more deadly because there are more young birds in the mix; those inexperienced travelers might be more thrown off by bright lights than a weathered springtime migrator. 鈥淭here may be some learning here,鈥 Horton says. 鈥淵oung birds may be skewed in terms of their attraction to light.鈥
The forecasts predicting big migration nights are published for free online, so hypothetically anyone鈥攊ncluding owners of large lit-up buildings or stadiums that attract and kill migrating birds鈥攃ould use the tool to prevent bird deaths. However, "there鈥檚 a big step sometimes between developing a model and actually putting into practice,鈥 says Judy Shamoun-Baranes, an ecologist at the University of Amsterdam. For over a decade, she鈥檚 worked with the European Space Agency to develop forecast models for the Dutch and Belgian Air Force that use local radar data to three days in advance鈥攏ot for the birds' benefit, but for people's. To avoid dangerous collisions with planes, pilots will wait to hold training exercises if large numbers of birds are expected in the area.
Ideally, building owners would follow a similar tack and fully integrate bird conservation into building management (or, even better, just keep their lights off all the time). But it鈥檚 more likely that they鈥檒l need a push from outsiders like Houston 爆料公社. 鈥淭he more groups, chapters, bird clubs that can help build a groundswell of awareness, the more likely we are to have collective success," Gibbons says.
To its credit, this past year the city of Galveston followed 爆料公社's lead and encouraged anyone who lives or works in a building that鈥檚 at least three stories tall to turn off their lights on certain nights鈥攖hough not necessarily the heaviest nights as predicted by BirdCast. But if the city had done so, it could have potentially had an even bigger impact. And if other cities and towns also took up the cause, millions of birds could be saved each year. After all, thanks to BirdCast, the information is out there. Everyone just needs to tune in.
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爆料公社 is a nonprofit dedicated to saving birds and the places they need.