How To Catch A Cat Part III: Setting the trap

This blog post is part of a series that covers how biologists go about catching the wild cats they study.  In the last post I described how to choose a trap site.  Once a trap site is chosen the next step is to actually set the trap.  Different kinds of traps are used for wild cat studies including cage traps and snares.  For use in research, each type of trap offers advantages, and for the purpose of this post, I'll cover how cage traps are set since I exclusively used this type for my bobcat research.

There are a few key tools used when setting cage traps. First, of course, you need the trap itself.  A lot of people ask me exactly what the trap looks like, and in the the pics below (that show the trap setting process) you will get a glimpse, but the traps I almost always use are heavy wire cage traps approximately 2 foot x 3 foot x 4 foot.  They have a single entry point at one end of the cage, and at the back of a cage is a wire treadle plate that when the animal steps on it, the door shuts.  In addition to the cage itself, I always maintained a "tool bag" that I used for setting traps.  In my tool bag I carried a hammer, wire, fishing line, scent lures, a hand shovel, a cloth bag, and a GPS unit.  When trying to trap an animal, it is very important to understand the biology of that animal. Cats, wild or domestic, are very visually-oriented creatures, and so it is important to cater to their visual sensitivity. That's why, among the tools in my tool bag, are always visual lures ones such as a feather pillow, a couple of antlers or bones, and old CDs, big feathers, or old soda cans that can be used as ornaments around the trap to attract the attention of animals.

In my last blog, I described picking a trap site and so once I know where I need to carry and set the trap, I gather all my tools and the cage and head off to the trap site to set the trap.  The cage itself weighs around 35 pounds, so that, along with the tool bag, can make for an interesting walk to the trap site if it is far or through a heavily vegetated area.  For some sites, a 20 min walk can easily double if you are carrying a huge and heavy cage with you.  The benefit though is that it gets you in shape fast if you are setting traps regularly!
When I set the trap that I'll describe below, it was luckily an easy spot not too far off from a human hiking trail The picture below shows a spot I picked out to set a trap. Vegetation in the Santa Monica Mountains can be very dense, so it is hard to tell but it is just on the edge of a natural animal trail, is flat, and is a position that is just between two sage bushes which will be great for disguising the trap. The red arrow in the photo below shows where the trap will be set.


Once I get to my trap site, I set all my tools down, and in the photo below you can see the cage along with my tool bag while I'm getting ready to set the trap.  Here you can see only half the cage, the feather bag inside the cage, and my toolbag on top of the cage.  

 

 Next, I put the cage in position.  I want it sandwiched between vegetation with the door to the cage just about flush with the animal trail.  This way, any bobcat that walks along the trail won't miss the trap.  It can be quite difficult to get a wild cat to go in a cage trap, but a great first step is making sure that the trap is in a position along a trail that increases the odds a bobcat will actually see whatever lure is inside the trap. I always try to have my traps so that the door is not only flush with the animal trail, but that the trap itself is perpendicular to the trail so that no matter which direction a bobcat may be walking along the trail, it will have equal opportunity to see whatever lure is inside the trap.  In the photo below, I have set the trap in the position I want it.

 

In the pics below, there's a great view inside the trap.  Here we are looking into the cage trap when the door is set open.  In the photo on the left, notice that the bottom of the trap is a hard wire mesh. Because bobcats are ambush predators that like to sneek up on their prey, they can be sensitive and deliberate about where they put their feet.  They are very careful not to make too much noise when hunting since it might alert their prey. Often, the visual lures that are put inside a cage trap to entice a cat inside will resemble potential prey for the bobcat.  In the photo on the right, I've placed a decoy foam rabbit, with the nose of the rabbit facing the back of the cage.  From this view, we see the decoy from behind and it resembles the white tail of a rabbit.  If a bobcat is tricked by this decoy, it may try to stalk and then pounce on it, so I always try to disguise the bottom of the cage with dirt so the bobcat won't feel the hard wire mesh on the bottom.  Putting dirt in the bottom also lends the cage stability, which is another great way to try to eliminate as many "unnatural" things about the trap as possible.  These photos give a great view of the treadle, or the "plate," in the back of the trap where the animal needs to step to trigger the door to shut.  Its hard to see, but the treadle is linked with a chain that controls a bar that keeps the door open.  If the treadle is pressed, the chain pulls the bar, releasing and shutting the door.

 

Now that the cage is in place and there's dirt on the bottom of the cage, it is time to start disguising it!  That means gathering a lot of vegetation to put both inside and outside the trap.  On the inside, the treadle needs to be disguised.  On the outside, the trap itself needs disguising so that bobcats that see that trap from the outside don't get suspicous before they even get close enough to see what's inside.  In the photo on the left below, grass goes on the treadle underneath the foam rabbit.  On the right, I've started to put vegetation all around the trap to make it look more natural.

Next, I start putting the finishing touches on!  Vegetation is put on top of the door, and I make sure that all the vegetation on the outside looks natural and is relatively stable.  The vegetation should stay in place even if it gets a little windy at the trap site.  In the photo on the left (below), the red arrow is pointing to the front of the cage trap.  At this point, its hard to even see where the trap is, which is what I'm shooting for!  It looks natural on the landscape.  In the photo on the right, I've put some white feathers just inside the trap and on the trail.  These feathers will help grab the cat's attention when it walks by the trap, hopefully getting the cat to stop and take a look inside the trap and be enticed by the fake rabbit.  The feathers come from the feather pillow that I have prepared with my other cage setting supplies.

At this point, the trap setting is done!  Before I leave the trap, I test the treadle to make sure the trigger action of the trap is just the way I want it, and that if a cat enters the cage and steps on the treadle, the door will shut properly.  When its all done, I'm ready to head out to set another trap, check what traps were already set, or head home for the day.  Now, it can be hard to even see the trap, although the feathers are a dead giveaway!  

 

Heading out, I take one last look at the trapsite (photo below).  Now it really blends in to the landscape (red arrow pointing to trap below).  I'll be back early the next morning to see if I've caught anything.  In total, it usually takes about one hour just to set a trap. Despite the hard work, it's always fun to set a new trap because it really brings on a feeling of total optimisim that you may catch something very exciting in it!

During the next blog post, I'll cover what actually happens when I've caught a bobcat in a trap.  I'm heading out of town next week to visit another urban carnivore study area in South Africa, so it'll take me a few weeks to get the next post up.  Sorry for the delay, but maybe I'll also have a good story to tell from South Africa!