Wildlife lovers are calling for monitoring of animals after a bird was ensnared at the Wetlands.
A tweet from @Green_Balcony reported a visitor to Walthamstow Wetlands had seen a bird ensnared in discarded twine "left to suffer in the water".
The tufted duck caught in fishing wire on Thursday was rescued by rangers and returned to the Wetlands.
The ten reservoirs at the site offer a haven for overwintering wildfowl, such as pochard and gadwell, and breeding birds such as grey heron, tufted duck and little egret.
Additionally, swifts visit during the spring and kingfisher and peregrine falcon can be seen all year round.
A Walthamstow Wetlands spokeswoman said: "We had a report that there was a tufted duck caught in fishing wire today.
"The bird was rescued promptly by the rangers onsite and released in good health.
"This is an unfortunate, but rare, occurrence, and our onsite team monitor the wildlife onsite daily."
The Wetlands is a Site of Special Scientific Interest, part of the Lee Valley Special Protection Area and is on the Ramsar List of Wetlands of International Importance.