Norfolk Wildlife Trust (NWT) raised concerns about the popular Halloween decorations after animals were found tangled in the synthetic webbing.
The sticky nature of the decorations, usually hung over bushes and trees, makes it easy for birds’ wings to get stuck in – exhausting them and leaving them injured by the struggle.
Bob Morgan, NWT Conservation Officer at Norfolk Wildlife Trust, said: “It may be tempting to use plastic Halloween decorations, such as fake spider webs, to add some seasonal magic to your gardens, but they spell real danger for our precious wildlife.
“These non-biodegradable decorations are a choking risk for local species such as hedgehogs, foxes and badgers.
“They can also tangle up birds and bats and disrupt spiders from making real webs.”
Instead, the trust has suggested embracing the county’s natural spooky occurrences instead of the fake plastic ones.
“From dead man’s fingers fungi to barn owls hunting at dusk, there’s nothing weirder and more wonderful than the wildlife we find on our doorsteps,” Mr Morgan added.
“By choosing eco-friendly alternatives you can make sure your celebrations do not become a true nightmare for Norfolk’s amazing natural world.”