New research has shown how extensively birds can be affected by New Year's Eve fireworks, with individuals being impacted up to 10 km away.
With data from weather radars and bird counts, an international team of researchers has revealed how many birds take off immediately after the start of the fireworks, at what distance from fireworks this occurs and which species groups mainly react.
The results of the study, which was published in Frontiers in Ecology and the Environment, prompted the researchers to argue for large fireworks-free zones.
On New Year's Eve, an average of 1,000 times as many birds are in the air close to where fireworks are set off as on other nights, with peaks of 10,000 to 100,000 times the normal number of birds. The effects are strongest within the first 5 km of fireworks, but up to 10 km there are still an average of at least 10 times as many birds flying as normal.
The results of the study prompted the researchers to argue for large fireworks-free zones (Jonathan Bull).
"We already knew that many water birds react strongly, but now we also see the effect on other birds throughout the Netherlands," said ecologist Bart Hoekstra of the University of Amsterdam.
"Birds take off as a result of an acute flight response due to sudden noise and light. In a country like the Netherlands, with many wintering birds, we are talking about millions of birds being affected by the lighting of fireworks."
Hoekstra's study looked at which species take off after fireworks and when this occurs. He used information from Royal Netherlands Meteorological Institute weather radars during both a clear New Year's Eve and on other normal nights.
He combined this with distribution data from Sovon – the Dutch Centre for Field Ornithology – based on bird counts by hundreds of volunteers.
"We already knew that many waterbirds react strongly, but it was still unclear how birds outside these waterbodies react to fireworks. Through the counts we know exactly where which birds are and using the radar images we can see where they actually take off because of fireworks," Hoekstra explained.
Using the data, Hoekstra was able to calculate how many birds take off immediately after the start of the fireworks, at what distance from fireworks this happens, and which species groups react.
The analysis makes it clear that in the study areas around the radars in Den Helder and Herwijnen alone, almost 400,000 birds take off immediately at the start of the fireworks on New Year's Eve.
Furthermore, it appears that larger birds in open areas in particular fly around for hours after and at remarkable altitudes.
The authors argue for fireworks-free zones in areas where large birds live. Hoekstra said "These buffer zones could be smaller in areas where light and sound travel less far, such as near forests. Furthermore, fireworks should mainly be lit at central locations in built-up areas, as far away from birds as possible. It would be best for birds if we moved towards light shows without sound, such as drone shows or decorative fireworks without very loud bangs."
Reference
Hoekstra, B, Bouten, W, & 7 others. 2023. Fireworks disturbance across bird communities. Frontiers in Ecology and the Environment. DOI: https://doi.org/10.1002/fee.2694
