Time for truth: free-roaming dogs are harming nature

Dogs on leads sign on a gate into woodland at Blickling National Trust in Norfolk

At the National Trust Blickling Estate, I look across the lake to the stately home. A Grey Heron is poised like a statue on the grassy bank. Jackdaws gather in the treetops, and I hear a Song Thrush. Two Great Crested Grebes dive close to the reeds where I saw a nest last year, opposite the bank with the ‘No Dogs’ sign the size of a beermat. As the sun sets, the parkland is peaceful. There isn’t a free-roaming dog in sight. But this is rare.

I can see why dogs are popular pets. Their companionship is good for mental health, they keep us active, and some people may even foster a closer connection with nature through walking their dog. Dogs are part of the family, so we want to give them a good life, and this includes exercise outdoors. But what about the impact on nature of 13 million dogs kept as pets in the UK?   

The number of dogs in the UK is trending upwards, with a surge seen during the pandemic. Since then, we’ve seen an increase in irresponsible behaviour by people walking dogs. Stories on social media reflect the frustration and desperation many of us feel about free-roaming dogs disturbing water voles along riverbanks, chasing waders and flushing nesting birds. But just how much of a threat are free-roaming dogs?

Free-roaming dog chasing wild geese in a field
Free-roaming dog chasing geese by Gisela Merkuur on Pixabay

Free-roaming dogs kill wildlife

Unlike cats that roam all hours predating birds and small mammals, dogs aren’t usually associated with killing wildlife. But a study of dog-wildlife interactions says unleashed dogs are a serious threat where encounters with wildlife are most likely. Published in Biodiversity and Conservation, the study analysed reports of dogs killing or harassing wildlife. It found that dogs attacked and killed 95 species, mostly mammals and birds. Over 90% of attacks were caused by free-roaming dogs in the presence of their owner in urban and peri-urban areas. 

Most dog attacks caused their victim’s death. The study found that even leashed dogs attacked wildlife, highlighting the need for dog walkers to be alert. With different laws and cultural views, the frequency of owned dogs roaming varies between countries. Likewise, the number of strays and feral dogs. But this study shows the potential for all dogs to harm and kill wildlife.

In the UK, local Red Squirrel populations are affected by dogs off the lead as The Wildlife Trusts explains. Even if free-roaming dogs don’t catch squirrels, the chase depletes their energy and causes stress. This can affect survival in winter when food is harder to find. In summer, squirrels may abandon their nest when chased by a dog. Young or sick hedgehogs are also vulnerable to dog attacks, likewise, adders, other reptiles and amphibians too.

Free-roaming dogs disturb wildlife

The Wildlife Trusts reports issues with dogs

With free-roaming dogs causing problems on their reserves, The Wildlife Trusts urges pet owners to keep wildlife and livestock safe. Bedfordshire, Cambridgeshire and Northamptonshire Wildlife Trust found unleashed dogs caused 40% of wildlife disturbances. This compares to 5% by dogs on leads. Lancashire Wildlife Trust reports dogs scaring ground-nesting birds and chasing livestock. 

Somerset Wildlife Trust has restricted dogs to public rights of way at two more reserves in the Avalon Marshes. “There have been increasing instances of dogs swimming in the lakes after sticks have been thrown into water. Dogs are disturbing birds and other wildlife including several instances of ground nesting birds abandoning nests after being disturbed by dogs. Fragile habitats have been trampled, wildlife killed, birds disturbed and chased, and grazing animals harassed and bitten.” Restrictions must be frustrating for responsible dog owners, but a blanket rule is easier to enforce.

Sign on a nature reserve coastal path asking dog owners to keep dogs on leads

Naturalists raise awareness of roaming dogs

While images of dogs on social media platform X mostly show their cute poses and playful nature, there is a growing awareness of the impact of free-roaming dogs on nature thanks to campaigners like Ian Denton and Jo Cartmell. Posting @NearbyWild and @WaterVole, Jo is especially concerned about water voles living along a riverbank in her local patch. Dog owners ignore signs, so roaming dogs cause constant disturbance to this small mammal, now rare in the UK.

Dogs disturb birds nesting on Norfolk’s beaches

With open public access, beaches can be more difficult to regulate. Around the UK, teams of wardens and volunteers are set to protect beach-nesting birds from the onslaught of visitors. At Winterton-on-Sea and Eccles beaches, the RSPB protects Little Tern colonies with electric fencing. At Holme Dunes, Norfolk Wildlife Trust’s signs along the coastal boardwalk alert people to birds nesting in nearby habitats.

However, restricting dogs’ freedom is contentious. Compliance can be problematic, especially among seasonal visitors who aren’t familiar with the local wildlife. Dog walkers pass large signs to keep dogs on leads at Holme, saying they didn’t see the sign. At Holkham National Nature Reserve, roped areas protect Shore Larks and Snow Buntings in winter and Little Terns in summer. But while birdwatchers with dogs know how important it is to keep dogs on leads, the wider public seem oblivious. Or defiant.

RSPB sign on the beach asking dog owners to keep dogs on leads to protect nesting birds

Rare Little Terns and Ringed Plovers in peril

When volunteering as a Little Tern warden, some dog walkers told me their dog wouldn’t hurt a fly. Others said they can do as they please in a public place. Many people aren’t aware that birds see free-roaming dogs as a threat. Birds waste energy when flushed from eggs or chicks, which are then exposed to the weather and wild predators. Adults and fledglings on the shoreline are flushed every time a dog is off the lead.

Ringed Plovers fare worse. Their nest scrapes are unlikely to be within electric fencing, so eggs are easily trampled or eaten by dogs. Chicks freeze when they hear a parent’s alarm call, but this works against them when the threat is a dog. To protect Ringed Plovers, dogs will be banned from a section of beach on Landguard Nature Reserve. Dogs may not be the main threat, but we need to minimise threats to maximise red-listed birds’ breeding success.

National Trust parklands overrun by dogs

A similar disturbance problem occurs inland. At Felbrigg and Sheringham National Trust, the electrifying Skylark is heard over meadows in summer skies. Signs ask visitors to keep dogs on leads. However, there is no sign in the meadow at Blickling where skylarks sing and dogs roam. It is expected that people will read the small print on notice boards, asking that dog waste is placed in bins and dogs are kept on leads around livestock. No mention of wildlife.

A tiny sign by the lake shows a dog crossed out (not exactly friendly or informative). Yet this lake is bordered by reeds, wildflowers, scrub and trees, a wonderful habitat for all kinds of birds. Over the past several years, I have enjoyed birdwatching in peace. However, this is becoming more difficult as the number of free-roaming dogs increases and fences are removed to give people wider access. More access often means less wildlife. And when dogs enter lakes and rivers, disturbance isn’t the only problem.  

Dogs compound environmental pollution

There are many causes of environmental pollution – crop pesticides, mega-farm animal waste, and transport and manufacturing waste to name a few. But the pollution related to dogs needs more attention.

Faeces and urine affect plant diversity

While many dog walkers might think dog waste is harmless, a study in Belgium says otherwise. The volume of dog faeces and urine deposited in nature reserves around Ghent created nitrogen and phosphorus levels that would be illegal on farms. Researchers say this is likely to be reflected across Europe due to the number of domestic dogs. High nutrient levels over-fertilise natural habitats, which allows dominant plants like nettles and hogweed to crowd out the variety of plants that wildlife depends on. Picking up dog poo and disposing of the bag responsibly removes most of the phosphorus but only half the nitrogen, the remainder being in the urine.

Flea, tick and worming treatments pollute watercourses

A study in 2020 revealed that toxic insecticides used in flea and tick treatments harm aquatic ecosystems in England, killing aquatic insects and, in turn, affecting the fish and birds that depend on them. Imidacloprid, which belongs to a class of pesticides known as neonicotinoids, was found to be present in English rivers in concentrations that exceed safe limits for wildlife. To show the scale of toxicity, Prof Dave Goulson says one flea treatment of a medium-sized dog with imidacloprid contains enough pesticide to kill 60 million bees.

Graphic showing the cycle of how dog flea and tick treatments pollute waterways
Flea treatment study in Science of the Total Environment February 2021

Scientists urge vets to cut treatments containing fipronil and imidacloprid, often used as a preventative treatment. These toxic chemicals, banned from use on farms since 2018, reach watercourses via sewage treatment works. Chemicals enter drains when owners wash their hands after treating or stroking their pets, or wash contaminated clothing and bedding. Once applied, chemicals remain in the skin, hair and excretions. Another route of contamination is when treated dogs enter ponds, rivers and lakes.

Worming treatments are also problematic. Many worming treatments tackle different parasites, including worms, fleas and mites. These products usually contain a combination of drugs, including imidacloprid. Worming treatments are often given in tablet form, but drugs can still be excreted in faeces or urine. 

Experts want toxic pesticides in treatments banned

Buglife first reported high levels of neonicotinoids in rivers in 2017, but the Government has taken no action. Buglife and environmental and veterinary organisations have sent an open letter asking the Government to ban five toxic pesticides. Pesticides in pet treatments don’t just harm wildlife, they affect human health too.

In a briefing paper, Imperial College London researchers consider the impact of flea and tick treatments on wildlife against the benefits (or not) to humans and dogs. Dr Andrew Prentis says: “Concerned cat and dog owners should talk to their vets about what is best for their pet, what is safe for the environment and whether such regular preventative treatments are needed. In the same way that we only take antibiotics when we’re ill – not every month – we may need to apply the same principle to parasite treatments for our pets.”

Many businesses thrive on the soaring numbers of dogs (and cats) and our affection for them, which drives sales of pet food, pet care products, and veterinary treatments. Even trusted online veterinary dispensary Animed promotes monthly flea and tick treatments in newsletters and blog posts without a word on the environmental impact.

There are natural ways to help our pets. Natural flea treatments include lemon juice or apple cider vinegar with specific herbs. Natural ways to eliminate worms from a dog’s gut include pumpkin seeds.

Dogs (and income) before wildlife?  

Over the past few years, I’ve seen changes at Blickling NT that seem negative for wildlife. The National Trust has partnered with pet food maker Forthglade in a Dogs Welcome project. Each National Trust property is awarded a paw rating. Blickling is a three-paw attraction, welcoming pooches into the café and giving them access to most of the parkland. Heritage properties are costly to maintain, so I appreciate they want to attract visitors. But the National Trust is also a partner in the Save Our Wild Isles campaign. Wildlife has already been pushed out with agricultural intensification, urban expansion, and “easy-to-maintain” gardens. To support wildlife in managed habitats like Blickling, we surely need areas where dogs can’t roam free.

Are people aware of the Canine Code?

The Canine Code is promoted on the Blickling NT website, but it isn’t displayed in the reception area or on notice boards. The code asks for close or effective control. This means “being able to recall your dogs in any situation at the first call; being able to clearly see your dog at all times (not just knowing they have gone into the undergrowth or over the crest of the hill); not allowing them to approach other visitors without their consent; and having a lead with you to use if you encounter livestock or wildlife, or if you are asked to use one.”

This code would exclude many of the dog walkers I see at Blickling. Owners watch their dogs leap into the lake, scattering geese and ducks, adults and young alike. I’ve seen a flock of Jackdaw alight from a field in winter, using up precious energy. There was no obvious reason until a dog came bounding from the vegetation. The owners were way down the path, chatting and oblivious. Jackdaws are not a threatened species, but dogs can’t tell a Jackdaw from a Skylark or a Curlew. Dogs off the lead can easily get out of control when they see wildlife, farmed animals or other dogs, especially when several dogs are being walked together. Dogs may be domesticated, but they are wolves at heart.

Dumping plastic bags of dog mess

When I see plastic bags of dog poo dumped behind trees, tossed into brambles, or audaciously left hanging from branches, I feel anger towards the polluters. Bags marketed as biodegradable or compostable often contain plastics, which don’t break down when left out in the open. Instead, they disintegrate into microplastics. The safest way to dispose of dog waste is in a bag made of cornstarch composted at home. Clearly, there are many responsible people who use the dog waste bins, otherwise, we would be knee deep in dog mess. I meet dog owners who care about wildlife and keep their dogs on leads, and I am thankful.

How can we encourage responsible behaviour?

The problem of wildlife disturbance and pollution is out of control, but there are ways to increase responsible behaviour.

  • Stay informed on sustainable pet ownership via websites like Pet Impact (set up by two pet-owning veterinarians) and spread the word!
  • Encourage dog walkers to follow the guidelines for dog waste and leads, setting an example as dog owners by using bins and keeping dogs on short leads during the breeding season.
  • Provide friendly, eye-catching signs to inform people about wildlife and restrictions for dogs.
  • Set up dog exercise areas in places like Blickling NT where dogs can run, socialise, and do their business with bins on hand, and leads used outside these areas.
  • Promote responsible behaviour to holidaymakers. I was heartened to see Holidays4Dogs giving advice to dog owners on how to protect wildlife.
  • Include open public spaces in new housing developments so people can exercise their dogs, and also areas of brambles and prickly shrubs to keep wildlife safe.

In national parks, nature reserves, parklands and beaches, nature organisations and local and national authorities face the dilemma of balancing wildlife conservation with keeping dog owners happy. But those of us who want to see less disturbance to wildlife and watch birds in peace should be heard too. The more people who know the truth about free-roaming dogs, the more chance we have of protecting wildlife, reducing pollution, and making sure the countryside can be enjoyed by everyone.

Article first published in the North East Norfolk Bird Club newsletter (March, 2024).

Banner image: Border collie by 825545 on Pixabay

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