Rodenticide poisons are still used to a large extent for rodent control, but rats and mice are not the only animals killed. Sometimes stone martens, polecats, foxes, owls, or even cats and dogs are exposed to secondary poisoning through eating poisoned rodents and die due to the amount of rodenticide accumulated in their bodies. Nature is brutal, but how brutal does it really have to be? How can we control rodents without harming or killing other animals in the process?
Rodenticides kill stone martens
The regulatory restrictions on the use of anticoagulant rodenticides (ARs) were tightened in Denmark, in 2011 and again in 2016. Permanent baiting using rodenticides for preventive control was banned. Today, a PCO must confirm or be able to prove, that there is an active problem before rodenticides can be used, and then they may only be used for a limited length of time. Nonetheless, many non-target species are still harmed by rodenticide every year despite these precautionary measures.
A 2017 study proved that even though rodenticide regulations have tightened over recent years, there are still many cases where rodenticides kill non-target wildlife. Especially stone martens can be in danger of becoming extinct, currently, they are listed as a vulnerable and endangered species and are now on the so-called ‘Red list’, which benchmarks the biological diversity in Denmark. The purpose of the red list is to assess which species are endangered and may become extinct in the short or long term.
Rodenticide poisoning is not the only reason as to why they are now endangered, but it does contribute to it. The body size of a stone marten is rather small and therefore they cannot eat many poisoned rats, the poison accumulates in the stone marten’s liver and eventually kills them.
Resistance to rodenticide
How do rodenticide poisons work? Anticoagulant rodenticides are blood-thinning; they disrupt the normal coagulation process of the blood. Once a rodent has eaten rodenticide, it typically takes 4-6 days before it results in death. Some people think that this is too long a process and an inhuman way of killing rodents, and believe it is against the Animal Welfare Act. However, rodenticides are still in use is that they are a highly effective tool in controlling rodent infestations and there are currently few effective alternatives.
Rodent populations can develop resistance to AGR’s to a greater or lesser degree and this trait may be inherited. Rodenticides have developed over the years and are now classified into two groups, older, first-generation, and newer, second-generation rodenticides, FGAR’s and SGAR’s. As resistance to the first generation of rodenticides grew in some areas, stronger second-generation anticoagulants were developed.
Therefore, there are now many different types of anticoagulants available (ARs). In areas of high resistance among rats, the SGARs are frequently used, but in areas where there is less or no resistance, PCOs often still use FGAR’s effectively.
Digital traps can replace rodenticide
Utilizing digital traps for rat control is an eco-friendly method of combating rats and in many cases can replace rodenticides completely. Many municipalities and businesses are now demanding eco-friendly rodent control. As a result, many pest control operators (PCOs) choose digital traps. Good news for the environment, stone martens and polecats, as it will decrease their risk of eating poisoned rodents and suffering a drawn-out death.
Rodenticides will likely be used for many years to come. Nevertheless, the use of digital traps is growing, helping reduce the dependency on poisons, and they are becoming an integrated part of the digital future within pest control.
- Danmarks Naturfredningsforening. (2020, January 15). Alle små mårdyr i Danmark er nu på rødlisten.
- Danmarks Naturfredningsforening. (2020, November 30). Rottegift kan dræbe små mårdyr.
- Lodal, J. (n.d.). Resistens hos rotter.
- Nisgaard, A. (2020, August 8). Rotter lider en 4-6 dage lang og pinefuld død: ‘Vi bliver nødt til at anvende de her gifte’.
- Smith, Rob & Shore, Richard. (2015). Environmental impacts of rodenticides.