Canid Pest Ejector (CPE) Data


Canid Pest Ejectors (CPEs) were first developed in the USA in the1930’s as a spring activated device for the control of coyotes. In the USA, the device was first called the ‘Humane Coyote Getter (HCG)’ and subsequently known as the ‘M-44’. Over many years they were adapted and improved to achieve the delivery of toxins directly into the mouth of a target animal. The spring activated ejector is not classified as a firearm by any agency.

Features of the device are:

  • The firm upward pulling action required to trigger the poison delivery, is easily achieved by foxes and wild dogs, but much less so by most non-target species.
  • Target specificity is further enhanced by the use of lure heads that do not attract herbivores.
  • Target specificity is further enhanced by the use of lure heads that do not attract herbivores.
  • The toxin used, sodium fluoroacetate (‘1080’), is highly toxic to canid pests (foxes & wild dogs) but has lower toxicity to native species.
  • Birds and reptiles are rarely able to trigger the device even if they show interest in the lure.
  • The device is staked to the ground by a sturdy metal peg and cannot be easily moved.
  • Devices may be set and left in place for extended periods (subject to local regulations) and can thus be used in long-term management programs.

The CPE device has been extensively tested in Victoria, New South Wales and Queensland to deliver a variety of potential toxins.

The first Australian trial was, supervised at the then Armidale Pastures Protection Board in 1955. This trial resulted in the control of 13 wild dogs and 36 foxes. More recently, from 2005–11, an extensive trial of ejectors to deliver 1080 to foxes and wild dogs was conducted under APVMA permits by the NSW Parks and Wildlife Service.

Example trial results in Australia:

The most recent trials have confirmed the effectiveness of the Canid Pest Ejector device as a delivery tool using 1080 to reduce fox and wild dog activity.

Monitoring of 98,299 lethal ejector nights across 7 sampling periods identified consistent sand-plot activity reductions in foxes averaging 78% across all sites, with a maximum of 93% reduction. This is comparable to what is achieved with intensive baiting programs.

Benefits of ejectors

The field trials also confirmed a number of benefits that make ejectors suitable for use as an additional wild dog and fox control tool:

  • Ejector capsules containing 1080 are sealed and protected from the elements so that the 1080 remains viable for extended periods in the field. Therefore the ejector can be set and left in the field for extended periods to provide a sentinel station, so long as the bait head remains attractive to target species.
  • CPE devices are pinned to the ground so they cannot easily be moved or cached by foxes, wild dogs or birds.
  • Once set, a CPE is only activated by a direct pull on the lure head that activates the spring loaded plunger to propel the contents of the capsule directly into the mouth of the wild dog or fox.
  • As the ejector can only be activated by an animal with an upward pull force of >1.6kg, many small non–target animals are excluded from activating ejectors. Researchers in Victoria identified that “only red foxes, wild dogs and feral cats had been recovered in field trials when cyanide was used as the active agent, suggesting a high level of target specificity” (Busana et al. 1998; Marks et al. 2003).
    NSW Office of Environment and Heritage (OEH) trials used monitored sand plots, remote triggering cameras and carcass collection to assess non-target risks after the use of cyanide (quick kill) capsules on 100,000 exposure nights. Few non-target activations were recorded despite many non-target animals being observed within close proximity to the devices.
  • Ejectors can be re-used many times.
  • Only 5 brush-tail possum carcasses were retrieved despite remote cameras recording 171 occasions where a brush-tail possum was present within 3m of a cyanide ejector during a total of 10,520 cyanide night exposures. Thus only 2.9% of brush-tail possum visits to ejectors resulted in activation. Longterm monitoring of sandplot activity on transects where 1080 ejectors were continually deployed over 5 years, identified brush-tail possum activity remaining stable or increasing. Thus no population impact on this non-target was recorded when using 1080 ejectors.
  • Lethal activations were recorded for only one goanna (from 1,050 cyanide exposure nights) and one swamp wallaby (from 3,510 cyanide nights). Remote cameras identified 315 occasions where a swamp wallaby was present within 3m of a cyanide ejector with only one lethal outcome. Neither nontarget would be affected by the 1080 dose used for control of foxes or wild dogs.

The combination of a low probability of activating an ejector, low non–target attraction to lure heads and greater tolerance to 1080 suggests that 1080 delivered through the Canid Pest Ejector will have minimal population–level impacts on native species.

  • Ejectors and spotted-tailed quolls.

An assessment of risk in known quoll (Dasyurus maculatus) habitat in the Paupong area of Kosciuszko National Park was conducted in May 2009. At each of 18 ejector sites spaced at 500 metre intervals 2 ejectors per site were monitored over 28 nights, giving over 1000 ejector-night presentations.

Quoll trials 2009

Spotted–tailed quoll investigating ejector Paupong May 2009

As the transect was located within a wild dog and fox control area, the ejector capsules contained 6mg of 1080. Spotted-tailed quolls were identified as being present within 1m of an ejector on 5 occasions at different locations. Despite quolls being strong enough to activate the CPE delivery trigger, no ejector device activations by spotted–tailed quolls occurred when ground dried liver was used as the lure head (Hunt 2010). Additional research in northern NSW has shown no adverse impact on quoll populations from 1080 baiting programs even though some baits may be taken by quolls (Kortner 2007, Claridge and Mills 2007).

Limitations of ejectors

  • Ejector devices are only effective while the bait head is attractive to the target species. If the bait head deteriorates, the ejector is less likely to be activated by a wild dog or fox. It is therefore important to check ejector heads periodically and to refresh any lure heads that are weathered, damaged or eaten by ants.
  • Ejectors are dangerous to working and domestic dogs because of the attractiveness of the baited head. Any unrestrained or roaming working or pet dog in the area may investigate and may activate an ejector.
  • Use of muzzles prevents dogs from activating CPEs.

Animal Control Technologies (Australia) Pty Ltd
46-50 Freight Drive
Somerton, Victoria, 3062
Telephone +61 3 9308 9688
Fax +61 3 9308 9622