Saving song birds with science – a look at their decline in the UK and the latest research to provide possible solutions
Song birds face critical declines
Song birds are in alarming decline with overall numbers fewer than half, compared to fifty years ago. Extinction remains a real threat for species such as nightingales (down 93%) and willow tits (down 94%) which have been part of our landscape and heritage for centuries.
At this time of year, the wonderful songs of the dawn chorus remind us of the remarkable birds we live alongside, but the volume is sadly diminishing. Song birds bring us joy and we are increasingly recognising the positive influence on our wellbeing. But the gravity of losing them from our ecosystem is about much more – it is signalling a crisis and research is providing critical knowledge to tackle this.
What is the latest picture?
The decline has been steady during the last half century, resulting in decimated populations of many familiar species. However, there is much variation hidden within the wider trend. A web of interwoven factors with a unique combination for each species, provide an enormous challenge when identifying and providing solutions to reverse the decline.
There is some positive news. Although in the minority, there are song bird species which are faring well. These include some regular garden visitors such as goldfinch (+134%)1, wren (+109%) and long tailed tit (+108%). However, looking more widely at these green listed species, we must be ever vigilant that green does not necessarily mean safe. Common favourites such as the blackbird, are green listed but numbers have declined by 15% in fifty years. Blue tits have increased by 26% in this longer period, which sounds positive but recently have started a downward trend. A new report from The Woodland Trust identifies an element of climate change as specific issue for this species. Spring is arriving sooner, and in the last twenty years is now on average 8.4 days earlier than seventy years ago. This creates a negative impact on breeding success. Different species respond in different ways to this earlier spring, and we now see trees leafing earlier and caterpillars, the food source for the chicks, being in abundance at the wrong time. This is just one example but demonstrates the intricacies of the threats to our song birds.
Farmland birds have been hardest hit in the last fifty years. Changes in agricultural practice such as loss of mixed farming and changes in crops grown since the 1970’s have played a major role, particularly affecting birds such as corn buntings (down 86%) and skylarks (down 63%). The rise of agri-environmental schemes were intended to provide a positive opportunity to re-build wildlife in the farmed land, but these are not producing the hoped for results.
The good news is that the findings of our latest research into pesticide use, has the potential to play a part in linking nature with farming systems again. It will inform farmers and thereby enable them to make better choices.
Spotlight on pesticides
Our current SongBird Survival funded study, is looking into whether use of modern pesticides (of which there are 300 different active substances in use) is contributing to the ongoing decline of farmland birds. This is being led by Professor Dave Goulson at the University of Sussex. So far, the research has found that overall toxic load due to insecticides, herbicides, fungicides and ‘other’ pesticides has decreased over recent years, partly due to EU bans and restrictions on organophosphates. Organophosphates (which are no longer used) were very poisonous to birds, whereas neonicotinoids are less toxic to birds, but much more toxic to insects. Thus the risk of birds being directly poisoned may have dropped, but the risk that insect-eating birds might starve is likely to have gone up.
Furthermore, new generations of active substances - 9 insecticides, 52 herbicides, 36 fungicides and 12 “other” pesticides - increased in the weight applied, and toxic load. Although these are not highly toxic to birds, they are used in large and steadily increasing quantities, so exposure to birds is likely to be high and growing. The University team is now planning to investigate exactly which pesticides turn up in feather samples from wild birds, to understand what harm (if any) they might be doing.
Recent years saw controversy over the role neonicotinoid insecticides may play in driving declines of bees and other insects. There is strong evidence linking neonicotinoids to bee declines, and incomplete evidence suggesting they may be driving declines of insects in general. Evidence has emerged that they may also be implicated in declines of birds - either via direct toxicity or via depletion of populations of insect prey. For example, in the Netherlands, rates of insect eating bird decline are higher in areas with more neonicotinoid pollution. A recent study from Switzerland found 100% of the feather samples taken from 146 house sparrows living on farms tested positive for one or more neonicotinoid.
The findings of the University of Sussex research are relevant to those with an interest in IPM (integrated pest management), an approach to managing pests, diseases or weeds whereby chemical pesticides are used only as a last resort, if at all. These stakeholders include land owners, farmers and others, such as policy-makers, who want greater knowledge to make better-informed choices about how they run their business vis-a-vis biodiversity, specifically of songbirds.
What must we do?
To re-build our UK song bird populations and amplify the dawn chorus volume, we must take action now. We must continue to find tangible and practical solutions. Science and data play a critical role in providing the information policy makers need to make change. At SongBird Survival we identify and fill gaps in the research landscape around song bird declines.
To find out more about our independent scientific research and what we do: www.songbird-survival.org.uk
1 All species trend data BTO/JNCC Bird Trends report
Launch of what3birds? for International Dawn Chorus Day
In the UK, the Tree Sparrow has fallen by 96%, the Willow Tit by 93%, and the Tree Pipit by 88% - in just 25 years!
British songbirds need our help, yet, few people are aware that UK songbirds have fallen by 50% in 50 years, with many species threatened by extinction.
For International Dawn Chorus Day (Sunday 2nd May), the charity SongBird Survival launches ‘what3birds?’ - a new campaign that challenges the public to do 3 things to help Britain’s beloved songbirds keep singing from the trees and rooftops:-
Spot 3 birds in their region
Plot their sightings on a dedicated map
Share what they have seen, and learn about the 3 at-risk songbird species in their region
BIRDSONG HELPED US THROUGH LOCKDOWN: NOW IT’S TIME TO GIVE BACK
Research shows that 4 out of 5 Brits say birdsong makes them happier, and 72% say it makes them less stressed. This was never clearer than during Lockdown. Indeed, twice as many people took part in this year's Big Garden Birdwatch - including 20,000 teachers and schools.
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