Hurricane Helene Impacts Fall Bird Migration in the southern Atlantic Flyway

 As the southeastern U.S. recovers from the 5th Hurricane Helene in history, birds that were flying in the southerly end of the Atlantic Flyway are beginning to recover. Hurricane Helene began as a tropical storm in the Caribbean, and then gradually transformed into a Category 4 hurricane as it hit Florida. Members of the annual fall migration often encounter storms like these, although they rarely get stuck in them. BirdCast, a website partnered with the Cornell Lab, Colorado State University, and UMassAmherst, uses weather predicting technology to forecast bird migration  and I am going to show you, using BirdCast graphs, how Helene impacted the travel of birds.
 

Before we start analyzing the data, I am going to show you how to read the information in the slides below. On the first slide there is a number in green, 6,119,400. This is the amount of birds that are flying over the state of Florida. Beneath that, in smaller fonts, there is the estimated direction, speed, and altitude. The last graph will delve deeper into the direction and speed. On graph two, we see that 2,150,100 birds crossed Florida. This number is smaller than the previous amount because not all birds cross Florida in a single night. Finally there is a graph at the end which has lots of little arrows that point mainly down and a little to the left. This means they were heading south-southwest.

Florida bird migration data on the night of September 23, 2024

If I wanted to, I could do the same thing for this graph as the Florida graph, but that would take forever! So I am just going to point out the major differences. First, the birds are flying almost half as fast and pretty much half as high. I don’t know why they are doing this, it could have something to do with being inland, weather, etc. Now that we have covered the pre-hurricane migratory average let’s move on to the day the hurricane hit!

North Carolina bird migration data on the night of September 23, 2024

Hurricane Helene hit Florida’s Bend area on September 26 at 2:00 pm. It altered the migration of birds days in advance, but all birds were grounded as the hurricane came roaring ashore. Birds typically migrate across Florida in the millions, but on the night of Helene’s rampage across the southeastern U.S. only 700,000 birds fully crossed the state. A lot of them were probably hiding out from the storm and weren’t flying around, but take into account that there is a hurricane and some of the weather towers – which is BirdCasts main source of information – were blown away. Similar things were happening in North Carolina, the number of birds in flight dropped dramatically, only eight thousand of the state’s typical millions were successful at crossing the state. 

Florida bird migration data on the night of September 26, 2024

North Carolina bird migration data on the night of September 26, 2024

As the final data point, we will explore the night of October 1st, a couple days after Helene hit. The first graph illustrates the amount of birds in the sky that night compared to the historical average. The line is almost three times as high and the next graph will help explain why. The last slide shows some bumps that start getting higher and then drop down to the bottom of the graph before flattening out. All of a sudden, the graph spikes, almost to the top. This is because all 64,688,100 of the birds that were hunkered down took off on the same night. I will not show you North Carolina data, but if you go to the BirdCast website, you can see that the birds departure is slightly more staggered. The migration then smoothed out and returned to the normal numbers. Currently, the migration has died down a bit, but watching the migratory frenzy from Hurricane Helene was highly rewarding to study and then share with you.

This is my first time using data like this in a blog, so if it was confusing I would love to have some feedback. If you would like to, please share in the comments which parts you enjoyed and understood and what parts were a little – or a lot – confusing!