Thursday 30 October 2014

How to: trap fussy marsupials (i.e. Antechinus)

Before you start work on a new species, it's generally accepted practice to read every single piece of literature about them that you can get your hands on, talk to anyone you can find who's worked on them before, and generally scrutinise every little thing that could go wrong and plan for it all.

They may look painfully cute, but at the risk of anthropomorphising, I think Antechinus are actually pretty devious. Image credit: Amanda Niehaus.

Unfortunately, I discovered that no matter how much you read about them, animals are always going to throw curve-balls at you - and in the end, nothing can beat actually getting stuck in and obtaining some hands-on experience, because everyone has different experiences and each species has their own little foibles. Regardless, I decided to write this little "how to" for others venturing into the world of Antechinus trapping. Some of my experiences might prove useful - and hopefully help minimise the amount of time you spend figuring out what the hell you're doing!

Sit back, relax, and remember the most important thing when working on a new species: try to stay calm. Image credit: Amanda Niehaus.

This year, my biggest task was establishing a breeding population of animals so that I actually have something to work on for the rest of my PhD. The very first step in this mission was to catch some animals in order to start up a study population. So, Amanda and I did some research to find out where our beautiful little target species lives, what habitat it prefers, where a large population is located, how other people have trapped them - we did all the paperwork and got all the permits, and then we set out - excited, expecting a few bumps in the road, but overall feeling pretty confident.

Each of our stainless steel Elliot traps was waterproofed using a plastic bag tied around the back end of the trap (we started off using large freezer bags, but once we realised how many we were going through we switched to biodegradable bags). Waterproofing is awesome for the animals inside the trap, but it is essential that you place the trap so that the entrance is lower than the back of the trap so that any water that does get in can drain out. We also put a handful of synthetic fluff from the inside of a pillow at the back of the trap, behind the bait, as bedding so the animal could stay warm overnight. Image credit: Amanda Niehaus. 

And then... we didn't catch anything. Not even a single bush rat. So, of course, we did some trouble-shooting. Were we trapping in the wrong type of habitat? "Open sclerophyll with a complex understory" might sound specific, but - as we discovered - when you apply it out in nature, it describes quite a variety of habitats.

Different types of open sclerophyll forest with a complex understory, none of which produced any Antechinus. Image credit: Amanda Niehaus.

We tried trapping a couple of nights in all of them without success. Then, on a whim, we decided to try out a little section of rainforest we had stumbled upon a few days earlier. Jackpot! First Antechinus, and about a bazillion bush rats.

Animals we trapped: Melomys, Antechinus, and the abundant bush rat. Image credit: Amanda Niehaus.

Even though we had found a population, our trap rate was still a little low. We also noticed that the Antechinus weren't really eating our standard bait mix of peanut butter and oats, which made sense given their primarily insectivorous diet. From our discussions with other researchers who had successfully kept Antechinus in captivity, we knew that they would eat most kinds of meat as long as they weren't too tough or stringy. So, we decided to experiment with different baits. We tried beef mince, chicken hearts, ox kidneys (which I don't recommend as their smell permeates everything), lamb hearts, kangaroo mince, liver... even roast chicken. However, we found that the optimal bait that both attracted the Antechinus and got eaten was beef mince mixed with peanut butter and oats.

The optimal bait: mince, peanut butter and oats. Tasty!

In addition to the bait, we also followed some advice we were given from my co-supervisor, Dr Diana Fisher, and used Antechinus-scented bedding in the trap. This completely outdid any sort of bait in terms of attracting Antechinus to the traps. We'd make up a big bag of scented fluff by placing a bunch of soiled bedding from the animals we had already caught in with a big bag of synthetic pillow fluff and leaving it out in the sun for a few hours, and voila - stinky Antechinus fluff! This worked wonders for trapping; because we were out there during the breeding season, male Antechinus were attracted to female-scented fluff, and females were attracted to male-scented fluff. Pretty cool, hey?

One of our little ladies with - yup - pouch babies! Like tiny little pink jelly beans. Image credit: Amanda Niehaus.

So, we managed to trap our animals. We didn't get as many as we'd hoped for, but it was a great start. And Antechinus, while being fussy and awkward, are also intelligent, personable, and frankly kind of a delight to work on - at least when they're not outsmarting you. I'm getting the feeling that I'll be writing a few more "how to"s before my PhD is up!

Antechinus trapping is fun - and check out the habitat we did get our Antechinus from. Image credit: Amanda Niehaus.

All images by Rebecca Wheatley unless otherwise credited.