A warning that Chinese lanterns could be dangerous to animals and livestock has come from Surrey Wildlife Trust (SWT).
It follows an incident where the charity's officers found eight lanterns in a field where cows were grazing.
SWT said animals could get tangled up in lanterns or eat the sharp parts, which could cause injury or death.
The lanterns, made of paper, wire and bamboo, and containing a lit candle, can float for miles before landing.
James Adler, SWT grazing officer, said: "We are very worried about the real threat that these lanterns pose to livestock.
"Please think about the consequences of releasing these lanterns; whilst they may momentarily light up your party they create a long-term, potentially fatal threat to wildlife and farm animals."
The charity has also warned the lanterns pose a fire risk to heathlands which are home to rare plant and animals species, especially during warm and dry weather.