Another Experiment Showing Very Low Predator Trap Interaction Rates
The Eastern Bays Songbird project has been going for 2 years and the members were keen to see how they were getting on with their goal of predator eradication. They have been using a 2040 Thermal Camera developed by The Cacophony Project to see what is going on around their traps. Their overall impression before deploying the camera was that they were getting the predator numbers down. They hoped the Thermal Camera would be a great way to get a full picture of the predators in the area. This camera was developed because standard trail cameras are designed for pig and deer and miss lots of the small moving mammals we are interested in here. In this entry, we share their findings.
To get a good picture of predator behaviour, the project set up a trap playground around a tree and pointed our thermal camera at them. The setup can be seen below.
The traps and tracking tools are listed below.
On the ground:
Goodnature A24 rat and stoat trap (on a stake) with recommended lure
Wooden rat/stoat trap - peanut butter
Coreflute tunnel rat trap - liquorice.
Timms trap - apple
Cage trap - apple
DOC200 - an egg
On the tree:
Goodnature A12 Possum trap with recommended lure (chocolate)
Two chew cards with peanut butter
Some choc flavored Goodnature lure spread around trees in the area
Blue visual marker for possums
We know it is not ideal to have so many traps next to each other but they really wanted to see if there were any predators around and which (if any) lures/traps seemed to work best.
The experiment was for 10 days between 4th and 14th on March 2020. Over that time there were:
198 videos
72 Visits from various critters (see below). If two videos are close together they are counted as one visit.
47-52 visits from predators (5 can’t be sure what they are but likely some form of predator)
Zero catches
The table below shows the summary of visits, captured from the AI-enabled Cacophony cloud services the camera uploads recording to:
Below is a video compilation of predator activity over the first four days - we haven't included the full ten days as the rest pretty much follows the same pattern and the predators just kept doing similar things.
The experienced trappers at The Eastern Bays Songbird project found these results eye-opening. They were surprised at how few interactions there were with traps. However, this is pretty much what we at Cacophony normally see in areas that have been trapped for a while. Data from lots of other projects around New Zealand confirms that predator interaction rates with traps must be very low. As a reminder we define an interaction as doing enough to trigger the trap. We'll discuss encounters and triggers later.
In some of the next blog posts we will explain how these types of observations lead to understanding the best types of strategy for improved trapping. It seems pretty obvious to us that automating and/or tweaking devices that don’t attract predators very often is not a productive strategy.
As always, we welcome your feedback so don't hesitate to get in touch - leave a comment below or email us at blog@cacophony.org.nz.
