Underrated Danger: Neonicotinoid pesticides may be more toxic to birdworms than previously thought, as is now the case from California. There, the proper treatment of the trees of the road with imidacloprid pesticides led to the sudden mass extinction of the golden ice creams. Birds were eating seeds with pesticides that lay beneath the trees – and poisoned them, as confirmed by the autopsy.
Pesticides are considered to be one of the causes of the dramatic fall of insects, but also the field and bird of the singing. Suspect is mostly neonicotinoids, agents that bind to receptors in the nervous system of insects and thus kill them. Three of these drugs, including imidacloprid, are now banned in the EU because of their damaging effects on bees in the field. For vertebrates, however, it was previously considered that neonicotinoids were less toxic.
A puzzling bird dies
But this is obviously a mistake, as is the case in California. In the morning of March 16, 2017 in the city of Modesto, 76 tree stalls were treated against insect infestation. The staff of the municipal garden office mixed Neonikotinoid Imidakloprid following the instructions on the packaging and sprinkled it on the rim of the trunk luggage – as the manufacturer noted.
On the same day in the evening, the inhabitants of the affected streets found at the foot of the trees numerous dead throat (spinus tristis). Small bird birds, weighing only twelve grams, fell dead to the ground, while others seemed to fall from the trees. To come to the root of this sudden mass extinction, Kryst Rogers from the California Wildlife Research Laboratory and her team collected 27 of these dead birds and subjected them to autopsy.
Cause of pesticide death
Result: The small golden throat obviously did not die of illness or exhaustion. "All the birds were in good physical condition with adequate fat reserves and well-developed muscles," researchers reported. Instead, hunger was obviously condemned to small singers. Almost all of the golden throat foods are almost gone before the deaths of the seeds of the street trees, while the fragments of the seeds of the seeds have been shown in its crop and stomach.
Toxicologic analysis confirmed the suspicion that "Imidacloprid is the cause of death for this golden age," Rogers and her colleagues report. Both liver and liver fluids measured elevated imidacloprid levels between 2.1 and 8.2 parts per million (ppm). For small birds, this dose is already sufficient to cause serious symptoms of poisoning and dying, the researchers explained.
Toxic effect on birds is underestimated
According to scientists, this case shows that the toxic effects of neonicotinoids such as imidacloprid on singing singers have so far underestimated. Small birds, in particular, quickly absorb pathogenic and even deadly doses of these pesticides through seed and insects that are transmitted to the soil – even if they are properly dosed and properly used. "Investigating mortality under stress highlights the previously overlooked risk of imidacloprid infusion," says Rogers and her team.
Researchers therefore recommend minimizing the use of this pesticide, especially when planting trees and other treated plants. "In addition, measures should be taken to prevent small animals from accessing treated areas," they say. Generally, however, they argue that instead of using pesticides, they should generally focus more on preventative, biological measures against pests.
Joint responsibility for the loss of birds?
In Europe, the use of open imidacloprid has been banned since 2018. But it is doubtful that the resources previously used in this country played a role in falling field and singing. Obviously these pesticides not only damage the birds indifferently, making their food insects scarce – and can poison them directly.
However, it is still not clear to what extent other neonicotinoids are similarly toxic to poultry and other small animals. Since many of these agents have a similar mechanism of action, it seems at least not excluded. Further studies will surely have to follow. (Toxicology of Environment and Chemistry, 2019; doi: 10.1002 / etc.4473)
Source: Society for Toxicology and Environmental Chemistry