In what was thought to be birds picked up on the radar turns out to be butterflies!
The National Weather Service (NWS) in Boulder, Colorado, tweeted Tuesday an interesting radar signature in what they thought were birds.
Look at what's flying into Denver! Radar from last hour showing what we believe to be birds. Any bird experts know what kind? #ornithology pic.twitter.com/EAqzdMwpFU
— NWS Boulder (@NWSBoulder) October 3, 2017
After suggestions on the type of birds by enthusiasts, it wasn’t cranes, waterfowl, swallows or blackbirds after all.
During day r limited options for flocking migrating bird species (most migrate at night) but cranes, waterfowl, swallows, blackbirds possble
— Jeff Wells (@Bird_Wells) October 4, 2017
Instead, the NWS says the real flying creatures picked up on the radar were butterflies!
1/4: We believe migrating butterflies are the cause of yesterdays radar signature. Thanks for all the reports and sightings! #cowx
— NWS Boulder (@NWSBoulder) October 4, 2017
2/4: Insects rarely produce such a coherent radar signature. Migrating birds do all the time. #cowx
— NWS Boulder (@NWSBoulder) October 4, 2017
3/4 Things with big wings need to fly together in the same direction with the wind to generate that signature in ZDR (purple image). #cowx
— NWS Boulder (@NWSBoulder) October 4, 2017
4/4: Migrating butterflies in high quantities explains it. Today, the butterflies are staying close to the ground. #cowx #Science pic.twitter.com/rkpwmPRnsi
— NWS Boulder (@NWSBoulder) October 4, 2017
And while the NWS says that insects rarely produce such a coherent radar signature, this was one of those rare times where migrating butterflies in high quantities explains it.
If you noticed the influx of butterflies over the last few months, you are not alone.
Painted lady butterflies make their migration to warmer climates typically from late summer into fall in search of their food source.
“You will see more or less butterflies migrating each year depending on the prior weather conditions (i.e. more rain > more plants > more caterpillars > more adult butterflies),” said Sarah Garrett, a Curatorial Lepidopterist at the Butterfly Pavilion in Westminster, Colorado. “From what we have seen the last week it has been a productive summer!”
Favorable Temperatures Lead To Increase in Painted Lady Butterflies