Millions of birds fly into the air in our country as soon as the fireworks start on December 31. Not only geese and ducks, but also other birds take to the airspace in large numbers. They stay on the blades for a long time. On New Year's Eve, there are on average a thousand times more birds in the sky than usual, with peaks reaching 100,000 times the normal number of birds. Even ten kilometers away from the fireworks, the effect is great. This is clear from the new Dutch research published this month in Frontiers in ecology and the environment.
The biologists who led the research, from the University of Amsterdam (UvA), have been sounding the alarm for years. It is one of the few groups in the world that uses weather radar – such as KNMI Radar – to investigate bird disturbances on a large scale. in Behavioral environment They reported in 2011 The birds remain in the air en masse for at least 45 minutes after New Year's Eve, with maximum density at an altitude of 500 metres.
Last year, researchers from Wageningen and Texel, also partly affiliated with the UvA, published Another notable study. Together with colleagues from Germany and Denmark, they analyzed data from hundreds of geese using a GPS transmitter. It showed that on New Year's Eve, geese fly an average of five to sixteen kilometers farther than usual, depending on the species – with outliers reaching hundreds of kilometres. During the first eleven days of January, geese spend an average of 10 percent more time foraging for food, to make up for the loss of energy. the magazine nature I picked up this article and released it late last year “Highlight the research”.
And now new research takes things even further. “Weather radar technology is improving rapidly,” says first author Bart Hoekstra of the UvA. “As a result, you can now see more detail – and thanks to better software, we can now also interpret that data better. You can now say more accurately: This is rain, and these are birds. This is important, because it often rains during New Year’s Eve.” New.
New technology also provides a lot of new information spatially. “This allowed us to compare weather radar data on the map with the results of bird counts, which are carried out in a very detailed and systematic way in the Netherlands,” says Hoekstra. As an example, he cites large-scale winter censuses of waterfowl, coordinated by the Sophon Bird Research Center in the Netherlands, and carried out by thousands of volunteers. But also bird populations in other areas, such as forests, meadows and cities. “That's great, because up until now we've been very focused on waterfowl,” Hoekstra says. We don't yet know how other birds react to fireworks. They now also appear to soar widely, although less so than waterfowl.
He also finds the large scale of the fireworks' impact alarming. “This effect peaks within the first five kilometres, but even at ten kilometres, there are still ten times more birds in the air on New Year's Eve than usual. This is really huge. Flying is one of the most energy-intensive activities for birds. So this is a “Very expensive to disrupt.” Hoekstra stresses that previous research on extra eating time in geese was limited to the first eleven days of January, but it may take several days before energy balance returns to normal.
Is all this reason enough to ban fireworks? “This is a political and social choice,” Hoekstra says diplomatically. We can only say: the impact is significant and widespread. “And it's not just the hour when we light the fireworks.”
Hoekstra points out that the Nature Conservation Act states that you may not disturb wild animals. “At least, not intentionally. So, if you know that something is causing such widespread disruption, you can draw your own conclusions from that.”
According to the researchers, a complete ban is not necessarily necessary; In their article, they argue for limiting fireworks to urban centers, or creating large fireworks-free zones around waterfowl areas. Hoekstra: “Think about the floodplains of major rivers. But also, for example, the Waterland district, the Biesbosch district and the Vichtplassen district.
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