Research Project

Birds and pesticides

Discover our Promises
Recent years have seen much controversy over the role that pesticides such as neonicotinoid insecticides, and herbicides such as glyphosate may be playing in driving declines of insects.

Evidence has emerged that they may also be implicated in declines of birds, either via direct toxicity of poisoned water sources, prey items and toxic-seed coatings, or via depletion of populations of insect prey.

The Project

SongBird Survival commissioned a research project with the University of Sussex funding two PhD students to understand pesticide use and how it may affect our UK songbird species. The use of pesticides and fertilisers has become a staple in the agricultural landscape and has allowed food production to increase as populations have grown, but the impact of these harsh chemicals is not fully understood.

The farmland bird indicator has been used to show the general state of wildlife in the countryside, and of bird declines UK wide for many years. It uses population information from the BTO for 19 different farmland species, many of which are songbirds. One of the reasons for the decline of these farmland birds is theorised to be in part due to pesticide use. The aim of this research project is to:

  • Find out what pesticide’s that farmland birds are exposed to and in what quantities using feather samples and trace residues in environmental samples.
  • Quantify exposure of birds and small mammals to pesticides via their consumption of pesticide-coated seeds following drilling of crops. This will be explored using camera traps and direct observation.
  • Model spatial and temporal patterns of population change in seed eating birds to see if they are predicted by patterns of pesticide use.
  • Examine whether the use of pesticides in gardens is influencing bird populations through population modelling and bird count data.
  • Examine pet hair used in nest building to see if flea and tick treatments could affect songbird survival and influence population changes.

We are starting to ascertain the catastrophic affects of pesticide use on our insect populations and that this is detrimental to our entire ecosystem.

Nick Mole, from the Pesticide Action Network UK said:

“Since the introduction of the ban on some uses of neonicotinoids in the EU there has not been any dramatic decrease in crop yield as predicted. But what we have seen is continuing evidence from research that the use of neonicotinoids poses an unacceptable risk to all pollinator species. It is vital that the ban on neonicotinoids is extended and strengthened when the decision is taken in 2017.”

The Results

  • There has been an 80% reduction in toxic load of pesticides, herbicides, and fungicides between 1990-2016. The weight of pesticides used has decreased by 51% in this same period, but the area treated increased by 63%.
  • Ethoprop was ranked the highest toxic load for 2016 and has potential for lethal and sub-lethal effects (such as reduced egg laying and decreased weight) in songbirds. 
  • 11 species were filmed eating pesticide coated seeds and analysis suggests that the insecticides imidacloprid, clothianidin and thiamethoxam represent the highest risk for grain-eating songbirds. 
  • The chaffinch was found to be most likely to receive a harmful dose of pesticide from seed treated grain and could consume 63% of LD50 (the median lethal dose that would kill 50% of animals tested) of imidacloprid in a single feeding bout, and 370% in a day.
  • Feral pigeon, robin, woodpigeon, and woodlark were also seen to be eating the coated seeds and could come to some harm if seeds treated with these other pesticides are consumed as readily as those treated with fludioxonil.
  • 34.1% of the gardens we tested used at least 1 pesticide and the use of any pesticide reduced house sparrow numbers by 12.1%. Where glyphosate was used, numbers reduced by 24.9%, and 38.6% when using metaldehyde.
  • The provision of bird-friendly habitats had a positive influence on bird abundance and diversity

The Solutions

This research project is still ongoing, but here are some initial solutions from the project so far:

  • Further work is needed to examine how seed palatability is affected by different seed treatments and how this varies between bird species.
  • Large quantities of treated seeds are left available for wildlife to consume after sowing and these are consumed by a broad range of farmland bird species. When extrapolated to other pesticides used as seed treatment this could lead to the ingestion of sufficient pesticide to induce sub lethal and lethal effects. These issues could be avoided with increased use of agri-environmental schemes or pesticide alternatives
  • Stopping the use of pesticides in gardens would reduce the negative impact on insect populations and so is a great step for garden owners to take at home.
  • Utilising natural means of pest deterrents is encouraged in domestic gardens, with companion planting and other home remedies like coffee grounds or eggshell for slugs as a potential alternative
  • To find out more information on where pesticide use is banned in the UK, see PAN’s website 

Meet our scientists

What is a Songbird?

Discover our Promises
Dr Cannelle Tassin de Montaigu

Postdoctoral researcher - University of Sussex

“Like a lot of children, I wanted to be a vet. But, one day, I saw a documentary about Jane Goodall and her relationship with wild chimpanzees, it completely changed my perspective on nature."

Dr Priyesha Tank

Researcher- University of Sussex

“I thought the only way to pursue my interest in nature and the environment was to follow in the footsteps of (the much more charismatic) Sir David Attenborough."

Professor Dave Goulson


Professor Goulson studies the ecology, behavior and conservation of bumblebees, with an interested in pollinators and pollination more generally, and particularly in the sustainable management of pollinators in agro-ecosystems. .



Tassin de Montaigu, C., Goulson, D. (2023) Habitat quality, urbanisation & pesticides influence bird abundance and richness in gardens. Science in the Total Environment.

Tassin de Montaigu, C., Goulson, D. (2021) Field evidence of UK wild bird exposure to fludioxonil and extrapolation to other pesticides used as seed treatments. Environmental Science and Pollution Research. 29: 22151-22162 

Tassin de Montaigu, C., Goulson, D. (2020) Identifying agricultural pesticides that may pose a risk for birds. PeerJ. 8:e9526


Gregory, R.D., Noble, D.GH., Custance, J. (2004) The state of play of farmland birds: population trends and conservation status of lowland farmland birds in the United Kingdom. Ibis. 146(s2): 1-13.

Hallman, C.A., Foppen, R.P.B., van Turnhout, C.A.M., de Kroon, H., Jongejans, E. (2014) Declines in insectivorous birds are associated with high neonicotinoid concentrations. Nature. 511: 341-343.

Millot. F., Decors, A., Mastain, O., Quintaine, T., Berny, P., Vey, D., Lasseur, R., Bro, E. (2017) Field evidence of bird poisonings by imidacloprid-treated seeds: a review of incidents reported by the French SAGIR network from 1995 to 2014. Environmental Science and Pollution Research. 24: 5469-5485.

Van der Sluijs, J. P. (2020) Insect decline, an emerging global environmental risk. Current Opinion in Environmental Sustainability. 46:39-42

Woodcock, B.A., Bullock, J.M., Shore, R.F., Heard, M.S., Pereira, M.G., Redhead, J., Ridding, L., Dean, H., Sleep, D., Henrys, P., Peyton, J., Hulmes, S., Hulmes, L., Sárospataki, M., Saure, C., Edwards, M., Genersch, E., Knäbe, S., Pywell, R.F. (2017) Country-specific effects of neonicotinoid pesticides on honey bees and wild bees. Science. 356(6345): 1393-1395

See our publication library for more of our research.