Use of rodent pesticides is suspected to be behind approximately 40 cases of predatory bird poisoning reported in Stellenbosch each year.
This was according to Hank Chalmers, owner of Eagle Encounters at Spier Wine Farm in Stellenbosch.
Stellenbosch Municipality has implemented bait stations around Stellenbosch over the last number of years “as a health and safety precaution”, according to Stuart Grobbelaar, spokesperson of Stellenbosch Municipality.
“A rodent bait station is a small, usually plastic, box with a hole that allows pests to enter. Inside the box is highly toxic bait, so any rodents that consume the bait will die,” according to the PestDefence website.
“Pest control is done at municipal properties as a health and safety precaution, and are serviced by a service provider on a regular basis,” said Stuart Grobbelaar, spokesperson of Stellenbosch Municipality. Pest control boxes are placed across town, including at the town hall, office buildings, ward offices and community halls. Private premises, such as Stellenbosch University, are responsible for their own pest control boxes, said Grobbelaar. PHOTO: Jana Scheepers
Detecting rodent poison
“Eagle Encounters treats mainly eagles and owls coming into the rehab centre, which have fallen victim to rodent poison,” said Chalmers. Eagle Encounters is a non-profit centre that rescues and rehabilitates predatory birds in Cape Town and surrounding areas, according to the centre’s website.
Symptoms of the ingestion of rodent poison in predatory birds include significant bleeding from the mouth, heavy breathing and lethargy, according to Chalmers.
“If something is lightly poisoned, you cannot naturally pick it up. If a bird comes in that is badly poisoned, you see that straight away,” explained Chalmers.
Environmentally friendly options
Rodents can become pests that spread diseases, according to Chalmers. As such, rodents can be killed, but in an environmentally friendly and humane way, in order for the ecosystem to remain undisturbed, he said.
“I always say to people: Poison is poison. Whether it is normal poison or environmentally friendly poison. If you want to catch rodents, get a rat trap, and do not use poison at all,” said Chalmers.
An environmentally friendly way of eradicating a rodent infestation is through the “peanut butter method”, according to Chalmers.
“Start with an empty 200 litre paint drum, which is buried in the ground filled with three quarters water, then put a wire along the top covered in peanut butter,” explained Chalmers.
The rodent will walk on the wire, eat the peanut butter and fall in the paint drum, said Chalmers. The rodent will drown, but the ecosystem will remain undisturbed, as the method does not pose a risk to other animals, he added.
Chalmers advised that people who want to use rodent poison should opt for poison that is less likely to result in death for predatory birds who consume it for the first time.
Educating the public on the negative effects of rodent poison will ensure an increased environmental consciousness, according to Matthew Mulvaney, a population geneticist and ornithologist at Stellenbosch University (SU).
“If a greater amount of the public are aware of the broader environmental implications posed by rodent poison, living environmentally friendly will come naturally,” said Mulvaney.
The Owl Box Project, which commenced in 2019, has constructed owl boxes at Wilgenhof, Minerva, the Old Main Building and the Forestry Building, as well as next to the Ertjieskloof dam on the Stellenbosch mountain, said John de Wet, environmental sustainability manager at the Stellenbosch University Sustainability Initiative. PHOTO: Jana Scheepers
An SU initiative, The Owl Box Project, focuses on eliminating poisonous chemicals which are bad for the environment, according to John de Wet, the environmental sustainability manager at the SU Sustainability Initiative.
The initiative will ensure a higher population of owls in the urban areas of Stellenbosch, which will serve as an “environmentally friendly pest control method”, said De Wet.
Hank Chalmers, owner of Eagle Encounters at Spier Wine Farm in Stellenbosch, explains the effect of rodent poison on the environment. AUDIO: Sourced/Hank Chalmers