The impact of neonicotinoid pesticides on farmland birds

Neonicotinoids (NNs) are widely used systemic insecticides which protect crops against a range of insect pests particularly aphids.

NNs were first introduced in the UK during the early 1990s and their usage has since spread to include oilseed rape, cereals, linseed, sugar beet and maize. A recent EU-moratorium has prohibited NN usage on flowering crops like oilseed rape but these pesticides are still widely used on cereals and sugar beet.

Evidence is growing of detrimental impacts of NNs on a wide range of non-target organisms particularly pollinating insects like honey bees and bumblebees. Exposure of bees through pollen and nectar has been shown to affect their homing behaviour, foraging ability and colony size, while contamination of soils and water is probably affecting a wide range of non-target invertebrates.

NNs are mainly applied at the time of sowing as coatings to crop seeds. Birds are potentially vulnerable to NN exposure when NN-coated seeds are left exposed on soil surfaces after crop sowing operations.

A small-scale survey of recently sown fields in Cambridgeshire (autumn 2013), indicated that pink-coloured NN-coated cereal grains are widespread in the arable landscape both as a thin scattering over entire fields, and as dense spillages on field headlands and margins.

• To assess the extent to which NN-coated seeds are left exposed on soil surfaces at crop sowing.
• To assess NN residues on surface seeds and in growing crops.
• To identify the species of birds and mammals most likely to consume NN-coated seeds.
• To assess the likely impacts of NN-exposure on bird survival and behaviour.

• September-December 2015: First season of field assessments of exposure risk.
• September-December 2016: Second season of field assessments of exposure risk.
• September-December 2017: Assessments of NN exposure on the survival and behaviour of partridges.

During 2015 and 2016 we measured surface seed densities, seed depletion rates, NN residues on seeds and seedlings, and bird and mammal species potentially foraging on spilt seed. NN residues are being measured by CEH (Lancaster).

Work in the autumns of 2015 and 2016 were conducted on fields sown with wheat on two contrasting soil types in arable farmland in Eastern England.

We measured the extent of NN-treated seed left exposed on soil surfaces at sowing and the rate at which these seeds disappeared. We also measured NN residues on spilt seed and in growing crops.  

We recorded bird and mammal species seen foraging on recently sown fields, and consuming NN-coated seed at concentrations of seed spillage. The latter involved the deployment of motion-sensitive video cameras to record daytime and nocturnal seed consumption.

A separate collaborative PhD study based at the University of York is attempting to measure the impacts of NN exposure on avian ranging behaviour and survival. 

• University of York
• Centre for Ecology and Hydrology (CEH)

• RSPB
• University of York