One of the largest contributors linked to the declining bee population in recent years has neonicotinoids, a class of insecticides not unlike nicotine. At this point, it is well known that bees are absolutely critical to our survival, as they are responsible for pollinating upwards of 70% of the crops that make up 90% of our diet.
In addition to the damage done to the bee population, a new study in Nature Sustainability has shown that neonicotinoids are also causing a drop in the bird population.
While bird populations have been steadily dropping anyway — the authors note that the bird population in the United States has dropped by an estimated 29 percent since 1970 — the researchers were able to separate out the general drop in bird biodiversity from the specific drop that appeared to be due to neonicotinoid spraying.
The pesticide that caused bee colonies to collapse is killing birds now
Neonicotinoids are used at a much lower rate than non-neonicotinoids, but they are radically more toxic to the environment. Birds are able to ingest neonicotinoids when they eat crop seeds or insects, and there is a correlation between the consumption of the pesticide and a decline in bird populations.
The study found that a 100kg increase in neonicotinoid use per county resulted in a 2.2% decrease in grassland bird population, and a 1.4% decrease in non-grassland bird population as well as a 1.6% decrease in insectivorous bird population and 1.5% decrease in non-insectivorous birds. The effects of these pesticides becomes larger over time as there are fewer and fewer birds able to mate and reproduce.
As further evidence, scientists also found a positive correlation between a decrease in neonicotinoid usage and the bird population.
After ingesting the pesticide, birds lost weight and waited longer to migrate. Neonicotinoids have also had a negative effect on the reproduction of both birds and bees.
In the long run, the negative effect on the birds and bees will also negatively impact crop yeild and production as well as human health. While we’re already seeing the side effects of neonicotinoid usage, it is likely the problem will get continue to get worse.