Dead cygnets spark pollution fears at city lake

Emily Price 

Calls have been made for an investigation into possible pollution in a popular city lake following reports of sick and dead cygnets.

A number of social media posts have highlighted concerns about the health and deaths of cygnets in and around Roath Park Lake in Cardiff in recent weeks, with one resident claiming two dead birds had been found within the space of two days.

One resident who waded into the lake to retrieve a dead cygnet described the water as smelling strongly of “sewage”.

“The water absolutely stinks. It’s worse than I ever imagined,” they said.

“A lady and lovely older gentleman watched over me and helped me out, although the smell brought tears to our eyes.”

The resident said they could not see any obvious physical injury to the young swan and claimed the condition of the water was responsible for the birds’ deaths.

In a separate Facebook post, another resident said the bird had been taken to a vet and claimed its death was “sewage related”.

They wrote: “The cygnet has been fished out by my friend who basically risked her own life to get him out.

“She did because we feel that the council is far too inept to investigate what is killing the swans and we are sure it’s sewage which the council refuse to clean and will happily leave the birds to die.”

The local said they would report the matter to Cardiff Council’s parks department and urged others concerned about the birds to do the same.

Some Facebook commenters questioned whether avian flu could have been responsible for the deaths, but the resident rejected the suggestion, saying they believed the cause was “quite clearly sewage related”.

They claimed this had been “confirmed by a vet”, based on the smell of the bird when it was taken to the veterinary practice and the condition in which it was found.

Dŵr Cymru Welsh Water told Nation.Cymru that its foul sewer network is not connected in any way to the watercourse at Roath Park.

Further concerns were raised by another visitor to Roath Park last week, who said a dead juvenile swan had been lying in an overhanging willow tree near the lake for several days.

They called for the bird to be removed, expressing concern that its decomposition could pose a risk to other wildlife.

Two weeks ago another local reported a sick cygnet “covered in flies, looking distressed and panting” near the boat house at Roath Park, adding that they had reported it to the RSPCA and Cardiff Council’s parks department.

The claims have prompted calls for the condition of the lake and the deaths of the birds to be investigated.

Roath Park Lake is a man made reservoir formed by a dam structure that is fed by the Nant Fawr stream.

Cardiff Council told Nation.Cymru it was not aware of any current pollution incidents affecting the lake but warned locals not to enter the water.

A council spokesperson said: “Bathing in Roath Park Lake was prohibited many years ago due to issues with the water quality and we would advise residents not to enter the water for any reason.

“If a member of the public sees a dead bird then this can be reported using the Cardiff Gov App or by calling 029 2087 2087 and our parks team will attend to remove it and, if appropriate, ensure testing is completed to confirm a cause of death.

“The Council is not aware of any current pollution incidents affecting the lake. Decaying organic matter present within the silt which naturally occurs in the lake can sometimes produce an unpleasant smell.

“The quality of the water that flows into Roath Park Lake is not something the Council has control over.

“However, we understand there are some long-term issues with unauthorised wastewater discharge entering the watercourses that feed the lake which continue to be investigated by the relevant organisations.”

Cardiff Council told Nation.Cymru it is not responsible for the condition of the water that flows into Roath Park’s lake and pointed us to Natural Resources Wales and Welsh Water.

A  Dŵr Cymru Welsh Water spokesperson said: “Our foul sewer network is not connected in any way to the watercourse at Roath Park.

“All our sewer assets in the area are operating as they should.”

Natural Resources Wales (NRW) said it had investigated several pollution reports in the Roath Park catchment over recent years and that they believe the issues are linked to wastewater from private properties being incorrectly connected to surface water drainage systems.

An NRW spokesperson said: “We continue working with Cardiff Council and Dŵr Cymru Welsh Water to investigate water quality issues in the catchment.

“We have carried out drainage surveys in the area to help identify pollution sources.

“However, this is a complex issue and pinpointing the exact source can be challenging due to the size and complexity of the drainage systems in the catchment.

“Anyone who suspects a pollution incident should report it to us via our online form at naturalresources.wales/reportit or by calling our 24-hour incident hotline on 0300 065 3000.”

The concerns come after Roath Park Lake was affected by an avian flu outbreak in December 2025, following reports of dead birds in the area and a confirmed case nearby in Cardiff Bay.

The Animal and Plant Health Agency confirmed that two swans found dead at the lake had tested positive for avian flu, while the RSPCA had to humanely euthanise several other distressed swans with suspected infections.

In early June, the overarching Avian Influenza Prevention Zone restrictions across Wales were completely lifted.

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