The UK’s complex and dense road network is helping common birds to thrive, but is having a disastrous impact on some of Britain’s most loved species.
Rarer, small-bodied and migrant bird species, such as meadow pipits and lapwings, are impacted the hardest by exposure to Britain’s 246,000 miles of road.
Birds are not only killed by collisions with cars, but by toxins emitted by exhausts, light pollution and noise, which disrupts their ability to detect prey.
While roads and their verges also provide heat, food sources and habitat for birds, common species, including rooks, blackbirds and robins, reap the benefits at the expense of others.
This could lead to the rarer bird species dying out, bringing about the simplification of the nation’s wide variety of bird communities.
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A Singing Tree Pipit (Anthus trivialis) perched on a hawthorn branch. Rarer, small-bodied and migrant bird species, such as meadow pipits and lapwings, are negatively associated with road exposure in Britain
‘In general, nationally common species are found in higher relative abundance around roads, while nationally rarer species are found in relatively low abundance around roads,’ said Sophia Cooke at the University of Cambridge.
‘Around roads it isn’t just individual bird populations that differ but entire communities.
‘This could be leading to something called simplification, or homogenisation of bird communities, where although high numbers of some species are maintained, diversity decreases.’
A common blackbird. The study suggests that road networks create environmental conditions that benefit common bird species (including rooks, blackbirds and robins) at the expense of others
‘We see this in urban areas – you aren’t likely to spot many rare species in cities, but you will find lots of pigeons and corvids.’
Britain has one of the densest road networks in the world, with 80 per cent of land found within a kilometre of a road.
If Britain’s 246,000-mile road length were laid out end to end, it would wrap around the world 10 times.
Northern Lapwing (Vanellus vanellus) immature at the water’s edge in Cley Marshes Nature Reserve, Cley-next-the-Sea, Norfolk, UK August
A stunning male Blackbird (Turdus merula) perched on a fence. The ‘compression’ of vulnerable species into areas of low road density may lead to declines and extinctions in countries with high road densities in the future
In the past 50 years, traffic on these roads has increased by more than 160 per cent and over the same period there have been large declines in many bird species so it ‘makes sense to question whether there could be a link between the two’, Cooke said.
Road construction can lead to fragmentation and changes in local habitats with effects on local populations of wildlife.
However, the impacts of roads on wildlife populations at national levels are poorly understood.
Carrion crow perches on a wooden fence. Species with smaller national populations generally have lower relative abundance with increasing road exposure, whereas the opposite is true for more common species
Using data from the UK Breeding Bird Survey, Cooke and colleagues assessed the abundance of 75 bird species in relation to roads across Britain.
The authors found that the abundance of 58 species was significantly associated with road exposure, of which 33 species were negatively affected.
As exposure to roads increased, species with smaller national populations decreased in numbers whereas common species increased.
For example, the meadow pipit experienced a 31 per cent decrease in abundance, whereas the Eurasian bullfinch experienced a 28 per cent increase when road exposure was taken into account.
A tree pipit stands proudly on the trunk of a tree. The study found the meadow pipit experienced a 31 per cent decrease in abundance near roads
Photograph taken off Great Cross Avenue in Blackheath, South East London, in the London Borough of Greenwich. Here we see a European robin (Erithacus rubecula), also known as the Robin,
When major and minor roads were analysed separately, 81 per cent of species found near major roads were negatively affected.
The compression of vulnerable species into areas of low road density may lead to declines and extinctions in countries with high road densities in the future.
‘What is particularly worrying here is the scale of our findings – the mean distance from a road within which reductions in abundance can be detected, was 700 metres,’ said Cooke.
A Close up of a juvenile Rook (Corvus frugilegus) asking its parent for food. Picture taken in Swindon, Wiltshire, England in June this year
70 per cent of Great Britain is within 700 metres (about 2,300 feet) of a road, meaning the effect will be widespread.
Cooke said more research is needed on the severity of the effect of roads on species, not just in the UK, but globally.
The RSPB said in a statement that the research shows how Britain’s infrastructure network forces nature into ‘smaller and smaller spaces or expecting it to fit in with our needs’.
A Skylark (Alauda arvensis) perched on a fence post singing. Picture taken at Swindon, Wiltshire, England in June last year
‘In planning a new road we can look at the loss of habitat and damage to existing wildlife, and assess whether this cost to nature of this is too high before any concrete is poured,’ said an RSPB spokesperson.
‘Once a road is constructed many of us will be familiar with the sad sight of hedgehogs, badgers and other mammals that have been injured or killed by traffic.
‘Smaller animals like birds are less easy to see, which makes this report really valuable in highlighting the impact a new road might have on local wildlife and how we might solve this.’
The study has been published in Nature.
Researchers claim the Earth is going through a ‘man made’ sixth mass extinction with the ‘biological annihilation’ of wildlife
The world has experienced five mass extinctions over the course of its history, and experts claim we are seeing another one happen right now.
A 2017 research paper claimed a ‘biological annihilation’ of wildlife in recent decades has triggered the sixth mass extinction and says the planet is heading towards a ‘global crisis’.
Scientists warn humanity’s voracious consumption and wanton destruction is to blame for the event, which is the first major extinction since the dinosaurs.
Two species of vertebrate, animals with a backbone, have gone extinct every year, on average, for the past century.
Currently around 41 per cent of amphibian species and more than a quarter of mammals are threatened with extinction.
There are an estimated 8.7 million plant and animal species on our planet and about 86 per cent of land species and 91 per cent of sea species remain undiscovered.
Of the ones we do know, 1,204 mammal, 1,469 bird, 1,215 reptile, 2,100 amphibian, and 2,386 fish species are considered threatened.
Also threatened are 1,414 insect, 2,187 mollusc, 732 crustacean, 237 coral, 12,505 plant, 33 mushroom, and six brown algae species.
More than 25,000 species of 91,523 assessed for the 2017 ‘Red List’ update were classified as ‘threatened’.
The number of invertebrates at risk has also peaked.
Scientists predict insects may go extinct within 100 years as a result of crippling population decline.
The dawn of the mass extinction coincides with the onset of the Anthropocene – the geological age defined by human activity being the dominant influence on climate and the environment.