Cane Toad Control Strategies
Cane Toads have a number of behavioural traits that make them vulnerable to control through people action.
They are fairly large, slow moving and like to move into open areas to feed, making them fairly easy to find. It is these things that make toadBusting or the manual collection of toads by people effective. Sadly it takes a lot of effort to completely eradicate toads from and area with this method, but it does work and even a little bit makes a difference to the numbers of toads in an area.
They also seem to be attracted to lights (or the insects that come to the lights) and so can be trapped in significant numbers in the right conditions.
The biggest factor that makes toads vulnerable is a biological weakness, their vulnerability to water loss through a process known as evaporative water loss.
Their skin is porous allowing water to soak in, and out, depending on conditions ! Toads evolved in the wet tropical regions of South America where there is rainfall and moisture throughout the year. They do not have burrowing, aestivation ( A process where their body functions slow down), or other water conservation strategies like our Australian native frogs. Just think for a moment and you will realise that virtually none of our native frog species are active in the Hot late dry season in the top end. They all have strategies they have developed to cope with long periods without water!
This weakness in the toads make up causes some to die each Dry season but most of them survive by moving to a water body. This is why we see such massive congregations of cane toads around water in the Dry season. Research from Prof. Ross Alford and Dr. Mike Letnic and observations from our own work indicate cane toads have to get to a moisture source every 4 to 6 days, and in some parts of the NT in the hot dry season around October they may need water every second day.
The fact they are forced to move to a water source and stay there for the Dry period, (research indicates they do not move more than 400 metres from the water for the entire dry period) is what we call the “congregation effect”. It is this more than any other factor that makes cane toad control feasible in the Wet Dry tropics and probably means that local toad populations could be eradicated in periods of drought and long hot dry periods in summer in other parts of Australia.
The sign to tell you when this effect has started is when the numbers of male and female toads are about equal around the waters edge at night. During the wet season the females do not stay near the water unless they are ready to lay eggs. They spend their time away from the main water bodies. Our wet season surveys find over 95% males around water, our Dry season surveys about half and half.
While cane toads are stuck in such locations is the time to get rid of them. ToadBusts at this time are much more effective and fencing and other control methods work best as well. The single most effective way to get rid of cane toads is to use an exclusion fence to stop them getting to their water source. In this way you can get rid of every toad at a site within a few days!