Fireworks can cause stress to birds in the wild, a study of Greylag geese in Austria suggests.
Researchers fitted temporary transmitters to 20 wild Greylag geese at Almsee, a lake in Upper Austria which is close to villages that hold midnight fireworks displays to mark the new year.
The transmitters record the birds’ heart rate and body temperature, which are measures of physiological stress.
The study, led by Dr Claudia Wascher of Anglia Ruskin University, recorded that the average heart rate of the geese increased by 96%, from 63 to 124 beats per minute, in the first hour of New Year’s Day, from midnight to 1am.
Their average body temperature increased by 3% (from 38°C to 39°C) in the same time period.
Between 1 am and 2 am, after the fireworks had ended, the geese’s average heart rate was still 31% above normal while the average body temperature remained 3% higher than normal.
It took around five hours for the geese to display normal body temperatures, with average readings only returning by 5 am on January 1.
The wild geese in the study were part of a resident population at Almsee and the researchers found no evidence that age influenced their physiological response, indicating that geese do not become desensitised to fireworks over time, according to the researchers.
Lead author Dr Claudia Wascher, Associate Professor in the School of Life Sciences at Anglia Ruskin University, said: “Ours is one of the first scientific studies to examine whether fireworks disturb wildlife.
“There have been previous studies showing that fireworks can cause anxiety in pets, for example in dogs, but little research has been done into how animals in the wild respond.
“In Austria, New Year’s Eve fireworks begin at midnight and last for several minutes.
“We believe the increase in physiological stress recorded over a number of hours is a combination of increased physical activity caused by the geese taking flight while the fireworks are being set off, and psychological stress.
“This causes the birds to expend additional energy at a time of year when food is scarce.
“We need to carry out further research to conclusively tell whether the geese are responding to the noise or the light pollution from the fireworks, or a combination of both.
“Many people get a lot of enjoyment from fireworks but it’s important that we consider animals – both pets and wildlife – whenever planning a display.
“It’s clear from our study that we should certainly avoid using fireworks in areas with large wildlife populations.”
The research is published in the journal Conservation Physiology.