Stoat Focus For 2023: Unit Evaluation Three Months On...

At the end of 2022 we started a long term deployment of units located at a area of trapping protecting a coastal area in South Taranaki.

The area has a considerable existing network and is having recorded captures in the past of stoats, hedgehogs, rats and feral cats.

In December 2022 we placed four units in an extension of this area.   The purpose of deploying the units was to again test the viability and reliability of the units during a long term deployment.   Once this deployment is completed we will spend time evaluating the effectiveness of the units and comparing this years data against the significant amount of historical data that is available.  

Of particular interest in this environment is the units being exposed to conditions that are coastal and the effect that it potentially would have on the effectiveness of the units.

As of March 2023 the units have now been deployed for just shy of three months.   The four units were placed inside three DOC 200s and a fourth was placed inside a rat box, as it was placed next to a larger cat trap where it could not be mounted.

All of the units are cycling through a two minutes delay have a regulation set up and battery save coded and are using the regulation batteries.        Three months into the trial the units are continuing to operate independently (that is they are still operating exactly as expected) and have done so without being altered or redeployed.   This is despite extremely wet weather with considerable rainfall.

We also have anecdotal evidence of increased feral cat presence at one of the trapping sites.   While we are not at a position to make comparisons of data at this point, this is obviously potentially encouraging and would fall in line with some of our earlier findings at different locations (where when cameras have been deployed we have clearly seen feral [and domestic] cats showing an interest in the units/sound.

Possum Activity - Recent Notable Incidents

 

The following series of incidents and images are from a local student who has been experimenting with the sound lure on their local farm and using it in conjunction with a Timms trap.   As part of this sequence a possum is visible in the first photograph on the left.  The possum investigates the area around where the trap is set and then activates the trap.

In this incident the sound lure was adjacent to the trap not inside the trap as is in some local deployed variation.

Following this successfull pest removal there was heighten actvity at the site as a number of possums interacated at the trap site.    During this time the sound lure was still operating and additional possums were arriving at the sight (this has been witnessed before at various locations locally).

There were also additional activations from two other animals of note during the monitoring timeframe.   

The first of which, shown in the third picture, is of a feral cat that was pulled into the activation area and spent time investigating the site and the location.  

While we are not targetting feral cats at this location and it is not outside of the realms of possibility that the sound lure is responsible for this visit (it has been evident on numerous locations throughout trials that feral cats are showing interest in the noise being generated from the boxes or the sound lure).

The final photograph in the series shows a visit from a Hawk to a location on the same farm where another possum has been caught using a Timms trap with a sound lure in operation.

Shortly on this site we will be running a prolonged trial involving a double blind set up to montior and measure the effectiveness of the sound lure.

Feral Cat Interacting with Feather

Further to identify the issue of the feral cat interacting wtih the feather sound lure (which has a small motor running in conjunction with the sound lure).

While this has been set up to base itself on attracting possums to the area with a small four watt speaker operating a variety of possum noises.   

Instead what has happened is that a feral cat has been dominating the deployment site for several weeks.   

This cat has been regularly appearing at the sound lure site.   Recently the feather that is working with the lure was placed so it was outside the netting for the rat box.

The result was that we had four intercations during a single evening between the cat and the trap.   The cat ignored the DOC200 containing rabbit meat and instead focussed its attention on the sound lure, and motor.

The cat also went to the extent of removing the feather from the inside of the trap as shown in the photograph.   It visited the site repeatedly during the night, four times in total and was photographed in excess of thirty times.

We have had expressed interest in the past from individuals who are focussed on looking at controlling feral cats and as a result we believe that this current set up would show considerable potential.

Feral Cats Dominating the Deployment

 

We have had significant feral cat activity which is now dominating the first deployment site.   This particular feral animal is showing significant activity and interaction with the sound lure, which is the trial version with the feather operating with a small motor.  This animal is being seen frequently in the area but is returning to the trap/lure and spending particular time focussing on the lure.

The photograph shown left is from a sequence featuring the feral cat.   There are two traps next to each other, the first is a DOC 200 which is baited with rabbit meat.   This is what the cat is sitting on in the photograph.   

The rat box next to the trap is fitted with a black T-Rex trap, with a regular sound lure and the feather motor.   

In the instances of the interactions from this series of photos taken in a single evening the feral cat approaches the location and spends time trying to enter or interact with the sound lure, while not attempting to do so with the DOC 200.   The time frame of the feral cat being involved with the sound lure was in excess of twenty minutes from its arrival at the location of the traps and remaining in the area while the lure repeatedly activated.    

It needs to be noted as well that the noise that is being activated from the sound lure in this case is a possum.   We have experienced in the past significant cat interest in the sound lure when the noise has a cat slant (such as featuring a chick noise).    

Further Developments from Ongoing Projects

 

It is currently the school holidays in New Zealand, we have a number of students who are currently running trials during the school holiday break, focussed on possums and using a sound lure in conjunction with a Timms Possum Trap, as seen left.    We have seen extremely encouraging initial results from these latest trials, including having possums entering into buildings (barns) to engage with sound lures and subsequently traps.   We have also have results coming from outdoor trials of the sound lures - again the initial results from these trials appear to be extremely positive showing increased possum activity at locations where the sound lure is being deployed.   These sites have double blind situations with two different locations on the same farm one featuring a sound lure and Timms and the other just a Timms.   Both locations are being monitored by Browning trail cameras.

At deployment site one we have noticed a significant change in the activity.   We have started in the last two weeks to use the 'feather' unit which is an adapted version of the sound lure.   There is the basic unit but we have the motor working in conjunction with the unit, when the sound lures is activated there is a motor that runs at the same time.   This is currently turning a feather, however we are going to develop this further trying addiitonal material and movement items.   At least one feral cat (pictured) appears to have taken up residence in the area by the river.   The result is that we have seen a significant reduction in mice and rats in the area.   While we have taken a short break with our recording at this location the cat was visible prior to the break starting and is now featuring significantly at the site.   We are not interested in trapping cats at this stage however the cat is shown significant interest in the lure, which is currently making possum noises. (We have in the past seen cats show significant interst in chicks or chirping bird sounds).

Finally we would like to acknowledge the support on Fonterra again to allow our project to continue with a stoat focus.   We also need to thank Bryan and Feral Control who are currently running trials for us using a number of our units.

This trial has not yet been completed however there are already some results of significance - the photograph on the left showing one of the 'distress rabbit' sound lure units which has been deployed inside of a DOC200.  As can be shown from the photograph a stoat has entered the trap and been disposed of as a result.

We are awaiting the results of this trial and looking to modify the units as a consequence of the feedback and the expertise that are available to us.   We will publish the full results of this trial when it is complete.  

Of considerable interest to us is this is the second time of recording a stoat strike on one of the sound lures in an unusually short space of time.  We have previously detailed how at the New Plymouth Airport we caught a stoat within three days of our first deployment at a location that stoats were not suppossed to be at.   While the capture above is not such an area, as stoats were known to be operating here, the capture is in a very short space of time - four days after the setting of the trap.