Poisoned rats infecting predators

As rodent numbers increase, so do poison sales

Turns out that ridding the cities and towns of rats may be contributing to harming most of the predators that feed on them.

A new report released today by Miljøstyrelsen, the Environmental Protection Agency, reveals that 99 percent of the animals that feed on rodents in Denmark become infected as well.

The report shows there has been a significant rise in poison use – both by municipal pest control services and private groups and people. From 2007 to 2013, annual sales of rat poison increased by 43 percent from 280 to 400 tonnes. Nevertheless, rat numbers continue to climb quickly.

READ MORE: Number of rats could increase dramatically

Universally toxic
”Rat poison has the same toxic effect on other mammals and birds and they can also be killed by the toxins,” Morten Elmeros, a senior adviser at the Aarhus University's Bioscience Department, told Metroxpress.

”They are not necessarily killed by ingesting a single poisoned mouse or rat, but the risk of toxic effects increases over time the more they eat.”

Predators that eat infected rodents suffer from stressed immune systems and internal bleeding.

The Danish Ornithological Society reports that one third of all buildings in rural areas use poison to rid themselves of rodents, and that the practice has led to them discovering dead owls and birds of prey filled with very high levels of poison.




Connect Club is your gateway to a vibrant programme of events and an international community in Denmark.


  • Barriers that internationals are facing in Denmark: presentation of the study and debate

    Barriers that internationals are facing in Denmark: presentation of the study and debate

    On Monday, 26 May 2025, Copenhagen Capacity will present the results of the Expat Survey 2025 at an event in central Copenhagen

  • An international’s book becomes a bestseller in Denmark

    An international’s book becomes a bestseller in Denmark

    As his book Quantum Humanitarian quietly reaches readers across Europe — recently ranked as the #1 hot release on Amazon in philanthropy, refugee studies, and conflict response, and a #1 bestseller in its category — Ali Al Mokdad reflects on the disconnect in modern aid work, and the quiet strength of those who lead without being seen

  • “Don’t erase who you are to fit in: STAND OUT—but with substance”

    “Don’t erase who you are to fit in: STAND OUT—but with substance”

    Ambre James-Brown didn’t just move to Denmark for a job —she stepped into a new life chapter, balancing ambition with vulnerability, and career with identity. As Vice President of Global Media & Stakeholder Communication at Novo Nordisk, she’s learned that success isn’t about assimilation. “I like to say I’m Dane-ish. More “ish” than Dane. I’m bringing the best parts of me to blend with the best parts of Denmark,” she explains.