Cane Toad Control Program
Cane Toad Control Program
Springfield Lakes Cane Toad Challenge – with the University of Queensland
History of Cane toads in Australia
Results of cane toad catching events
Project Background:
Cane toads (Rhinella marina) are exotic pests that wreck havoc in the environment. This occurs in two ways.
- They are voracious eaters of anything that they can fit in their wide mouths. An excessive toad population results in less food for native wildlife (especially birds, frogs and small mammals) and thus reduced populations of natives. If anyone has noticed the lack of Christmas beetles over the past number of years – blame it on the toads. Toads also eat dung beetles, which are one of the greatest success stories of biocontrol. Before dung beetles were introduces, cow pats just sat on the ground and built up a mass of flies that were vectors for disease. The Australian “cork hat” was an essential item of clothing before dung beetles started doing their job so well. See information on this issue at the following link http://www.sciencealert.com/cane-toads-are-eating-the-dung-beetles-that-keep-australia-clean.
- Being poisonous. Toad toxin is concentrated in their warty skin and secreted by two large parotoid glands behind the ears (it cannot “spit” poison at you). A sticky white substance, it is highly dangerous if eaten or rubbed into the skin or eyes. Their toxic mucus kills most native lizards and mammals that try and eat them. In urban environments, thus also includes pets such as cats and dogs. Ibis are one of the few animals that can eat cane toads with no problem, especially the toadlets. Thus the large number of ibis that are now seen around.
Objectives
- Enhance the biodiversity of our environment by reducing the impacts cane toads have on native wildlife
- Reduce poisoning rates of household pets from licking and ingesting cane toads.
- Build community capacity in frog identification skills so that residents can feel comfortable & confident in dealing with toads independently knowing that they are not killing native frogs
Rationale
Many Queenslanders consider the killing of cane toads as not merely a responsibility but a state birthright. However, being cruel to cane toads is actually unlawful under the Queensland Animal Care and Protection Act 2001, which means no cricket bats, golf clubs or kerosene baths. Note: people have lost sight in an eye when using the ubiquitous golf club, the toxin being squeezed out and squirting upwards on club impact.
We live with cane toads in our community but very few people would know how to identify a toadlet or the cane toad eggs.
Reducing the numbers of cane toads in the Springfield Lakes environment will allow the native wildlife here a chance to continue to exist and thrive. These pests cannot be eliminated, but they can be controlled so that they have less of an impact. Just reducing them from plague proportions to common, would provide a benefit to native wildlife, and for people walking around on lakeside pathways. Humans introduced this species to Australia, so it is up to us humans to become the top predator to control their numbers. Just imaging if every citizen of Springfield lakes killed one cane toad a week. There would be virtually none left!
Method
With support from an Ipswich City Council Community Development Fund grant, SLNC is running Toad Busting workshops and events in an attempt to encourage the community to combat this menace in a humane and environmentally safe way.
A key aspect of the initial workshops was to educate and train participants as to what is a cane toad and what is a native frog, as some frogs look very similar to toads, especially when small, and we don’t want to accidently kill the frogs that still live around our lakes.
SLNC engaged a qualified and experienced field ecologist, Kay Montgomery from Ecological Connections, to deliver these workshops to SLNC group members, other community group members, and interested people from the local community.
Training also involved how to safely catch toads and humanely handle and euthanise them. We also learned how to identify cane toad eggs and the best way to remove these from the water (a garden rake).
Initially the members of the SLNC group would be trained but when more events are held the wider public would be given instruction and education. Once people knew how to identify and eradicate the toads effectively, they could teach other residents, and this would help sustain the project.
The workshops would provide Free training to other community groups such as the Scouts so that they could educate their members and in turn they could hold a toad busting night themselves as the costs of holding the event are minimal eg only requiring dry ice.
The free workshops will provide information and educate residents on how to eradicate toads from the community and essentially a better educated community about cane toads
By repeating the experience through further events, it gives the members and public an opportunity to practice the skills and knowledge learnt, keeps the issue current in the community’s conversation which also acts as an avenue to promote education and awareness. The numbers of toads caught could be published in newspapers and on websites. This would enable the community to have ownership of a significant issue as they see themselves directly contributing to a common goal. We would promote the idea of volunteering to participate and giving something back to the environment as a worthwhile activity. Statistics show that connecting with nature and the outdoors does have benefits on people’s health and well being
After collecting toads (always wear gloves), which often congregate around park gardens under street lights, the animals that are confirmed to be toads are put into an esky containing dry ice. This frozen carbon dioxide is very cold and the toads go into hibernation, and as the dry ice melts it releases carbon dioxide, which eventually kills the toads. When the dry ice is totally melted, the toads are put into a freezer for at least 48 hours to make sure that they are dead.
Humane killing and disposal of cane toads
SLNC currently uses the “Stepped Hypothermia” method. We did use the exposure to CO2 (via dry ice in an esky) plus stepped hypothermia, but this became expensive and the supply of dry ice became very limited over summer.
Stepped Hypothermia
- Always wear gloves, thick rubber or gardening, when handling toads.
- Pick the toad up firmly, preferably with your hand over its back, place it in a plastic bag or plastic container and secure. Label clearly.
- Now place into your refrigerator (at 4°C) and leave for 12 hours. This does not kill the toad but does anaesthetise it. This length of time is essential and the toad must not be moving when placed in the freezer.
- Next, place the container with the toad into the freezer (-20°C) for at least 24 hours. This last step will painlessly kill the toad.
- Finally, dispose of the body in your wheelie bin. Alternatively you can bury the body, but this must be deep enough so it will not easily be dug up by dogs or native animals. Remember to wash your hands after each of these steps.
Handling of cane toads is best done by adults. Cane toads can also suffer distress from being chased excessively, so try to make their capture and handling as quick as possible.
For toad-busting outside of these SLNC event, the dead toads are disposed of in the weekly rubbish collection. However, SLNC is now part of the “Cane Toad Challenge”, and our captured toads have a different fate.
SLNC has signed an agreement to become an affiliate of the Cane Toad Challenge. The University of Queensland – Institute of Molecular Biology has developed a bait that attracts cane toad tadpoles (which SLNC calls toadpoles) and draws them into traps set in waterbodies. Hundreds of toadpoles can be removed each day. The bait is made out of the toxin from adult cane toads, either to attract the toadploes to a living adult toad so that the toad can have a good meal (cannibalism) or to attract the toadpoles to a dead adult so that the toadpoles have a good meal.
However, the researchers need to have a supply of toxin to make the baits. SLNC members cut (excise) the toxin glands off the dead adult toads, refreeze the glands, and then take it into the University and give to the researchers. In exchange, SLNC receives free baits to use in the toadpole traps that we have constructed. These traps consist of a plastic box with a funnel attached to the each end – narrow part inside, and the large opening facing the environment outside. The bait exudes the attractant out the funnels into the water, the toadpoles follow the scent back in from the funnels, then can’t find there way out (although they probably don’t want to leave).
The baits are only effective for about 24 hours and the trap needs to be checked, toadpoles removed, and baits replenished each day of use. If there is any bycatch of native frog tadpoles or native fish or other fauna, then these can be safely removed before taking the toadpoles out. Toadpoles are distinctive, and could only really be confused with the green tree frog tadpole. Both are black, but the toadpoles have a bigger head and narrower tail, and a totally transparent dorsal fin on their tail. The green tree frog tadpole has black spots on their transparent dorsal fin. The toadpoles are also killed humanely using the cool-freeze method, and then discarded in the weekly rubbish after death (48 hours in the freezer).
SLNC is conducting regular toad-busting sessions during the summer months, usually on a Friday night so school aged children can join in.
Learnings:
A number of identifying features exist for cane toads, but some are shared with native frogs so all all must be present to confirm that it’s a toad.
- Bony ridges over the eyes.
- Bony ridge along nose.
- Ear is visible
- Warty skin on back
- Large toxin gland behind the ear.
- None or only slight webbing between fingers and toes (cane toads use their feet for digging, not swimming)
- No suckers on fingers or toes
Cane toad identification fact sheet
The best way to reduce cane toad numbers is to collect and destroy the eggs before hatching.
- An average clutch of eggs, laid in a double strand in a long strand of gelatinous jelly, contains more than 30,000 eggs, more than any species of native Australian frog.
- The toads lay eggs a few days after rain, and the eggs hatch from them two to five days after.
- A garden rake is a good way to collect eggs, but you have to be able to identify them and there is only a limited window of time to collect them.
- The next best way to reduce cane toad numbers is to collect and destroy the toadpoles before they metamorphose into thousands of tiny jumping toads – which then can impact on native fauna.
- Cane toad tadpoles look different to native species. They are jet black with big nostrils and a wider body across the gills. https://youtu.be/h7WK59UCry4. They also swarm in groups is shallow still water,
The easiest way to tell a male from a female is to pick it up (being careful to wear sturdy gloves). A male will sound out a short trill, known as a “release” call. This release call is designed for use in mating. Amorous male toads are not fussy about what they grab and will often latch onto another male. The trill is the toad equivalent of “Sorry buddy, I don’t swing that way”. Some researchers have developed toad traps that attract female cane toads by using recording of the male toads call. The lower the pitch of the call, the more success.
SLNC has managed to purchase one of these traps – with assistance from Grill’d Burgers Orion “Local Matters Jar”.
Other cane toad trap designs can be found at here.
SLNC Toad Catching Events
SLNC has been running monthly cane toad catching events during the spring – summer – autumn active cane toad season -September to April (in other months the toads are hibernating). On the first Friday night of every month, we gather at the Spring Lake pontoon, near the Ashleigh Barty Tennis Court opposite the IGA. We teach new recruits about the differences between native frogs and toads, and how best to catch (minimum distress) and humanely dispose of caught toads. This allows them to undertake toad catching in their own neighbourhoods at any time, especially on warm after some rain. The results of these events are shown below.
Event Results:
