Poisoning cats – Week 2
By Jack Ashby, on 3 February 2011
A delayed account of zoological fieldwork in Australia – Part 2
From April 2010 I spent about five months undertaking several zoological field projects across Australia. I worked with government agencies, universities and NGOs on conservation and ecology studies ranging from Tasmanian devil facial tumour disease, the effect of fire, rain and introduced predators on desert ecology and how to poison cats. This series of blog posts is a delayed account of my time in the field.
Last week I ended the post the night before we began the search to find cats and native wildlife in Western Australia, and determine whether they had been poisoned by an experimental bait laced with a potent dose of local plant-based poison, 1080.
Each of our study animals had in recent weeks been trapped in a cage trap (more about them in future weeks) and had a radio collar fitted. These battery-powered collars each transmit a radio signal on a specific wavelength. The kind this team were using emitted a different signal if the animal was dead (fast beeps) or if it was alive (slow beeps).
Using this simple technology involved going into the Fitzgerald River National Park to the areas where the animals had been originally trapped and trying to find a signal. This meant standing on the ute with a radio antenna, set the the frequency of the collar we were looking for, and turning slowly 360 degrees.
If the signal was “live”, we made a note an moved on, if it was “dead” we had to collect the carcass for analysis – to see if the poison had killed it. Most of the time we couldn’t find a signal at all, even after driving around a lot. This probably meant that the animal was out of range.
We spent ten to twelve hours each day doing this. Early on we had found most of the bush rats, and had a few locations for the quolls (who we were most worried about poisoning). All were alive. We struggled to find the endangered dibblers, hopefully because they are so small that their collars don’t have aerials on them so the range is tiny.
One day we got a message from HQ that a colleague in a helicopter had a mortality signal from one of the cats, but it had seemed to be moving around (the signal source was changing). So we were asked to find it and check whether the collar was working.
We picked up the “dead” signal, so began to push our way through the thick malee scrub towards it. As we dropped down towards a large inlet, the direction changed – it seemed the cat had moved. We reached the water and got a very tight reading in a new direction on an outcrop across the bay. It then stopped moving.
The moving signal phenomenon was probably due to the water bouncing it around.
FUEL INCIDENT #1: We took the bagged carcass back to a freezer, and put the collar in the back of the ute. This is where we kept our equipment and the spare jerry cans full of fuel – given that we were in a remote area for a long time we had a lot of fuel.