AN AGE-OLD CONNECTION
Rats and mice are a problem for people throughout the world wherever we settle and grow crops. They can spread disease, have high economic impact when feeding on growing and stored grain and cause nuisance in many other ways. Methods to control rodents have varied including hygiene measures, trapping, control by domestic cats and dogs, providing roosts for Barn Owls and various means of poisoning with simple substances such as baking powder. Introduction of anticoagulant poisons such as warfarin from the 1950s tipped the balance in our favour. Some species were reputed to develop resistance in the UK. In the 1970s and 1980s manufacturers developed more potent ‘second generation anticoagulant’ rat baits which have become widely available. When ingested by non-target wildlife (and our pet dogs and cats), either directly or through prey that has fed on baits, these compounds are more potent, persist longer and are difficult to counter with veterinarian treatment.
A how-to guide to being Owl Friendly
A comprehensive document about the rodenticide threat to wildlife and how this needs to be addressed has been authored by Leonard Fitzpatrick, a Brisbane-based wildlife rescuer and dedicated rodenticide control campaigner. This is the end result of extensive research and collaboration with key stakeholders in the wildlife rescue/rehabilitation community, veterinary professionals, academia, and advocacy groups in Australia and North America.
Best not to kill first then ask questions later if you might catch a mardo, not a mouse
We have made a video step by guide for tackling nuisance mice and rats in gardens and houses in the Margaret River region without exposing our wonderfully varied wildlife to lethal rat poisons, directly and through the food chain.
Photo Mick Griffin
Phascogale. Photo B Wykes
RODENTICIDE PATHWAYS ALONG THE FOOD CHAIN
Rodenticides directly harm native wildlife such as bush rats, quenda and possums as well as their intended target of introduced rodents. They indirectly harm many more through ‘secondary poisoning’. Evidence is mounting that rodent baits are being eaten not only by the obvious candidates but also by reptiles, which themselves are quite resistant, and by invertebrates such as insects which are unaffected. This means that wildlife at risk of secondary poisoning includes owls, phascogales, brush-tailed possum, quenda, chuditch, mardo, dunnart, daytime birds of prey and insectivorous birds. Even if not directly killed by internal haemorrhaging, wildlife that have ingested rodenticides are more likely to hunt unsuccessfully, get ill, or be killed on roads.
Phascogale. Photo B Wykes
RODENTICIDE PATHWAYS ALONG THE FOOD CHAIN
Rodenticides directly harm native wildlife such as bush rats, quenda and possums as well as their intended target of introduced rodents. They indirectly harm many more through ‘secondary poisoning’. Evidence is mounting that rodent baits are being eaten not only by the obvious candidates but also by reptiles, which themselves are quite resistant, and by invertebrates such as insects which are unaffected. This means that wildlife at risk of secondary poisoning includes owls, phascogales, brush-tailed possum, quenda, chuditch, mardo, dunnart, daytime birds of prey and insectivorous birds. Even if not directly killed by internal haemorrhaging, wildlife that have ingested rodenticides are more likely to hunt unsuccessfully, get ill, or be killed on roads.
Phascogale. Photo B Wykes
RODENTICIDE PATHWAYS ALONG THE FOOD CHAIN
Rodenticides directly harm native wildlife such as bush rats, quenda and possums as well as their intended target of introduced rodents. They indirectly harm many more through ‘secondary poisoning’. Evidence is mounting that rodent baits are being eaten not only by the obvious candidates but also by reptiles, which themselves are quite resistant, and by invertebrates such as insects which are unaffected. This means that wildlife at risk of secondary poisoning includes owls, phascogales, brush-tailed possum, quenda, chuditch, mardo, dunnart, daytime birds of prey and insectivorous birds. Even if not directly killed by internal haemorrhaging, wildlife that have ingested rodenticides are more likely to hunt unsuccessfully, get ill, or be killed on roads.
ADVICE ON RODENT CONTROL
If baits are a necessity, choose only First Generation ones with active ingredients Warfarin (e.g. in Ratsak Double Strength, David Gray’s Rat ‘n’ Mouse Killer) and Coumatetralyl (e.g. in Racumin sachets and Couma blocks). Wildlife and pets can cope with these relatively well when taken in through secondary poisoning.
Masked Owl chicks. Photo S Castan
WAYS TO HELP TO PROTECT WILDLIFE AND PETS
Prevention is better – and cheaper – than cure when it comes to poisoned pets and wildlife. You have an important role through selection, storage and particularly through positioning of rat baits such that the baits themselves and the poisoned rodents don’t get eaten by non-target wildlife, pets and children.
You can also contribute to lobbying for stricter controls, requiring best practice by commercial operators, supporting funding of research, wildlife treatment and rehabilitation, and above all else maintaining habitat for our wildlife.
Masked Owl chicks. Photo S Castan
WAYS TO HELP TO PROTECT WILDLIFE AND PETS
Prevention is better – and cheaper – than cure when it comes to poisoned pets and wildlife. You have an important role through selection, storage and particularly through positioning of rat baits such that the baits themselves and the poisoned rodents don’t get eaten by non-target wildlife, pets and children.
You can also contribute to lobbying for stricter controls, requiring best practice by commercial operators, supporting funding of research, wildlife treatment and rehabilitation, and above all else maintaining habitat for our wildlife.
Masked Owl chicks. Photo B Wykes
WAYS TO HELP TO PROTECT WILDLIFE AND PETS
Prevention is better – and cheaper – than cure when it comes to poisoned pets and wildlife. You have an important role through selection, storage and particularly through positioning of rat baits such that the baits themselves and the poisoned rodents don’t get eaten by non-target wildlife, pets and children.
You can also contribute to lobbying for stricter controls, requiring best practice by commercial operators, supporting funding of research, wildlife treatment and rehabilitation, and above all else maintaining habitat for our wildlife.
ADVICE ON RODENT CONTROL
Masked Owl with rat Photo S Castan
DON’T MAKE DINNER A HEALTH HAZARD
Your choice of methods to control rodents can make all the difference to owls in your neighbourhood. Around human habitation, rats are a major part of their diet and the food they catch to raise their chicks.
Discovery of Quenda not rats in chook pen using non-lethal rat trap. Photo B Wykes
AVOID BAITS IF POSSIBLE
Before putting any pets and wildlife at risk from rat baits, firstly:
- keep your place clean and tidy, clean up brush piles and rubbish, secure compost heaps
- use poultry feeders which prevent spillage
- pick up fallen fruits
- seal holes and other potential entry points in buildings and enclosures
- use traps – a wide variety of traps is available; careful positioning is necessary to be effective and reduce harm to non-target species, particularly with lethal traps that ‘kill first and ask questions later’.
- Place all traps and baits out of reach of non-target animals – noting that setting baits and traps where there is a reasonable chance of killing or catching native wildlife is in fact illegal unless licensed.
Some suggestions for attracting rats into traps – pumpkin seed, nuts, dried fruit, roasted oats (roast them in a pan until they have a great nutty smell), bacon.
Do I have black rats or native wildlife?
Many of us have not seen small furry critters close up until one is caught in a non-lethal rat trap. Have I got a black rat problem or am I lucky enough to be sharing my garden with native rats or small marsupials? The National Museum has some helpful ID information.
https://australian.museum/learn/species-identification/ask-an-expert/is-it-a-rat/
RODENTICIDES AREN’T ALL EQUAL
“Second generation” anticoagulant rodenticides pose the greatest threat to wildlife and pets.
Active ingredients include difenacoum, brodifacoum, bromadiolone and difethialone.
SELECT BAITS THAT ARE LESS HARMFUL TO WILDLIFE
Check ingredients on the labels.
Anticoagulant rodenticides can be divided into:
Our wildlife has a higher capacity to cope with first generation rodenticides so we recommend use of Racumin, David Gray’s Rat ‘N’ Mouse Killer or Ratsak Double Strength (but take care not to confuse it with other Ratsak products) and Couma blocks – if and when all other means of rat and mice control have been exhausted.
The Health Department and local government require rodent control of commercial and institutional premises. This can be done using the less harmful rodenticides. Get advice from the Augusta Margaret River Shire.
If employing a licensed pesticide company, ask about their practices, ask them to use the safer rodenticides, and better still, choose one that recommends their use.
A recent addition to retail shelves are rodenticides ‘based upon natural products’ including Ratsak Naturals and Yates Natural. The active ingredients are corn gluten meal and NaCl (salt). The gluten, accelerated by the salt, apparently causes lethal flatulence because rodents cannot expel gastric gas in the manner we do. These are registered for use in domestic buildings and other indoor situations where alternative food sources can be removed. Well worth trying. Let us know how you fare.
