Fireworks are well-known to cause fear and anxiety in animals, and a new study shows wild birds are no exception.
Wild geese fly higher and further in response to New Year’s Eve fireworks. In the aftermath, the birds spend more time foraging and less time moving, most likely compensating for their efforts.
These are the findings of research published in Conservation Letters which tracked the movements of 347 wild geese over eight years in Germany, Denmark and the Netherlands in the period before and after New Year’s Eve.
Scientists from the Max Planck Institute of Animal Behaviour in Konstanz, Germany, and the Netherlands Institute of Ecology equipped adult geese – from four species white-fronted goose, bean goose, barnacle goose and pink-footed goose – with GPS transmitters contained in a backpack or neck band.
The researchers measured flight distance, roost site use, energy costs and foraging for twelve days and nights before and after New Year’s Eve.
The geese flew 5 – 16 kilometres further on average on New Year’s Eve, with extremes of up to 500 kilometres, averaged heights 40 – 150 metres higher than previous nights.
“It is shocking to see just how much further birds are flying on nights with fireworks compared to other nights,” says lead author Andrea Kölzsch.
The study used data on particulate matter (PM10) in the air as the most direct approximation of the amount of fireworks. During New Year’s Eve fireworks, particulate levels at roosting sites increased by between 324 – 655%.
“We find that birds are leaving their sleeping sites and choosing places further from people and with lower PM, which strongly suggests that they are trying to escape from the fireworks,” says Kölzsch.
There were two notable after effects. In the days following, the birds moved less and foraging increased, likely compensating for the energy used during the night of the fireworks.