Building a Low Pressure, Humane, Animal Trap

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Introduction: Building a Low Pressure, Humane, Animal Trap

Great Outdoors Contest

Runner Up in the
Great Outdoors Contest

I had a problem, I had a whole family of squirrels in my garage, I like squirrels- they are cute, and generally friendly.  I don't like them in my garage.

I don't blame them for wanting to be in my garage, it is pretty awesome in there, but it is a problem; they chew on electrical wires, poop, and there is also no food sources in the garage.  So they had to go.

I can borrow a commercial metal animal trap, but the issue is that I encountered right away was that the pressure plate in one of those requires a bit more force then a small squirrel.  So I was quickly able to catch mommy squirrel, but none of her children.  This is bad, now I have a bunch of baby squirrels in my garage, no food, and no way for them to get out.

I needed an animal trap that could be triggered by the minuscule weight of a baby squirrel, and hold them securely until I can release them.

Step 1: 1. Bill of Materials

To build this trap you will need:

Main body:
4x 2x2 cut to 1.2m
4x 2x2 cut to 35cm
2x board cut to 1.2m long, 35cm wide
2x Screen mesh 1.2m long 40cm wide
screening (cut to fit when complete.

Door:
1x board cut to 55x40cm
2x 2x2 cut to 30cm
2x 2x2 cut to 35cm
4x 1x2 cut to at least 20cm
small bungee cord

Teeter trigger
1x 2x2 cut to 1.2m long
2x 2x2 cut to 35cm
rope


Tools required:
Jig Saw
Drill
Hammer
Nail gun/staple gun
Brad nailer
round file

Consumables required:
Roofing nails
2in screws
3in nails
2in brad nails

Step 2: 2. Assemble Base Frame

At this point you will assemble two rectangular frames, be sure to pre-drill all holes, those 2x2s will not take a screw directly and the wood will split if you do so.

Step 3: 3. Form the Box

Attach the boards to the top and bottom of your frame, forming the box that will be the basis for the rest of your trap.

Step 4: 4. Attach Mesh Screens

Attach the mesh screen to the sides.

I used the roofing nails, as they slightly overlap the edges and hold everything well in place.  You could use staples if you have them long enough, or put another 1x2 on top and screw that down (again be sure to pre-drill)

Step 5: 5. Put the Back On

Using the thin screening cut to shape for the back of the cage and attach, I used a mixture of roofing nails and staples to hold this in place (the staples into the plywood boards because they will not split it, the nails into the 2x2s)

Step 6: 6. Begin Construction of the Front Door

The front door is a 'guillotine' style- don't let that scare you, the idea is it closes when the animal is nowhere near the door itself, and the trigger mechanism takes a lot of the weight off the door, so while it shuts with some speed (somewhat slower then gravitational acceleration) it does not have a lot of force behind it.

Step 7: 7. Build Front Door

Make a cut into the front door to leave a 'notch' just at the top line of the trap when the door is closed.  Make the exposed part of the notch slightly wider and taller then a 1x2.
This is where the lock will engage when the door drops

Step 8: 8. Build the Locking Mechanism

In order to hold the door down once it has closed some sort of locking mechanism is required, this simple setup is to carve a small notch into the back of a 1x2, in which a bungee cord will sit trying to push it forward against the door.  When the door comes down the notch we put into it will become exposed and the lock will engage, you will need to pull it back in order to unlock the door.

Step 9: 9. Build the Teeter System

The teeter is basically just that, a teeter-totter that holds on one end the trigger mechanism, and on the other the door.

Take a single 1x2 and notch it.

Cut a larger then 1x2 hole in the top of the trap.

Build up 2 2x2s vertically from the trap, and place the .5in metal rod through them and the teeter bar.

Tie both ends of the teeter bar to the trigger and the door respectively.

Step 10: 10. Optional Improvements

While your sawing away at the back of the trap in order to put the trigger mechanisim, you might want to make a nice big lockable panel so that you can more easily place bait inside.

The trigger meachanisim as provided is very gentle, so the animal only needs to brush it in order to set it off, but it only covers part of the cage, tiny critters may go around it, so enclosing it in a screen while depressed will increase the surface area of contact that the animal may brush it from.

Alternatively placing a 'flap' pressure plate way at the front of the cage leaning up against the trigger mechanism should assure that sufficient force to dislodge it is created by even the smallest lightest critter by the time they get to the bait.

Finally you could build a 'reverse teeter' hooked up directly to the bait, basically, assure that if the weight of the bait changes negatively, the trap triggers.  The downside to this is that the animal may be on its way out when the trap finally triggers, and getting the balance exact may be difficult, but it assures that if the animals has gone for the food it will trigger.

Carry handles would be nice as well, or you could reinforce the teeter mech so that you can carry it by that.

A 3d printed trigger notch, and rim- would really improve the sensitivity by assuring that you need far less lip to catch the mechanism then the rather coarse wood will allow for.  Milled trigger mechanism would be similarly effective.

Similarly 3d printed, or bearing sliders on the door would make for a more smooth closure.

Step 11: 11. Put Everything Together

Ok, now we can put everything together

Step 12: 12. Catch Your Critter, and Release Safely.

Set it up with some bait, and wait.

Wear gloves when moving the trap, your fingers may look tasty/threatening to the now caged animal.

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21 Comments

not enough detailed images.. giving up and looking for another design.. or just winging it

Just wanted to say congratulations on being a finalists in the Great Outdoors Contest! This was a fantastic instructable! Good luck!

as far as I know in Ireland, Red squirrels are protected (this trap could be trouble) but grey squirrels are vermin, they're invasive and kill/displace native reds.

Humanely capturing squirrels is a noble effort. I believe in live trapping myself. That way you can release any non-target animal that walks into the trap. However, we all need to be mindful of our local laws and impacts on the environment. In many US states ( not sure of other countries. ) it is illegal to transport a live squirrel off your own property. In this case, the only legal recourse is to hire professionals, or euthanize the animals humanely. Please check your local laws and educate yourself before dealing with an infestation of any kind.

This is most certainly good advice, however if one animal made it to a place you don't want it and you do nothing to prevent it from returning then even when you release the animal a league and a furlong away another one will just get in there. I don't personally understand the 'drive the animal so far away that it won't be able to find its way back' scenarios as a result. Release outside of the unwanted area AFTER you block further access.

In my case I'm only interested in squirrel out of garage. My first step was to identify the method of entry and block that. Further I have a nice 100ft tree on my front lawn, several more in the backyard, a massive carport, and a roof covered with solar panels (that have 4 inches clearance under them) that I am happy to have house as many squirrels as it will support. So I will normally release them just at the base of my driveway facing the tree (I figure if a family of what according to my current count is 9 squirrels can live in my garage with no access to food or water then the same number can pretty happily live in the tree or other parts of my outdoor household)

The reason why I bring this up is... I'm sorry... not good news for you. I've been through this. I sealed up all the holes nicely with wood, and metal mesh. I got all the squirrels out of the attic. Within a few days those buggers ripped open entirely new holes in the house right next to where I patched up. Doing more damage then before. I live next to a large park with 10 -20 large trees. I hope you have better luck. I do. Please message me and let me know how this goes. I might be able to offer some friendly advice.

Also, be careful with the trapped squirrels. Always wear thick gloves!

Not to seem negative, but it disturbs me when people refer to something being illegal, yet cite no source whatsoever. That's how internet rumors get started. So if you're going to refer to laws, cite your source from a reputable site. This person took a lot of time and effort to create a good instructable, I feel any comments that refer to it possibly being a criminal offense should be equally as thorough.

A quick google search only yielded one hit about it being illegal to move squirrels, and that was from a UK site.

My apologies. I have a serious pet peeve about internet rumors too. This, I will prove to you, is not one. Here is a citation from the Florida wildlife conservation commission. See the question "What do I do with a nuisance animal after it is caught?"

http://myfwc.com/conservation/you-conserve/assistnuisance-wildlife/faqs/

Here is another nicely written article by a guy with credentials in the nuisance wildlife industry. He also directly states that "without a permit you can’t legally transport that animal off your property"

http://blog.timesunion.com/wildlife/an-introduction-to-the-nuisance-wildlife-industry/251/

Many states have similar statutes in place. When you think about it really makes sense. Who are you to bring your problem to someone else's door step? In addition it could be quite cruel to the animal to be relocated.

NOTE: You used the term "criminal offense" which I don't believe is appropriate here. Illegal does not equate to criminal. Some actions dealing with a nuisance animal involving cruelty might be criminal. However, violating live transport laws is merely a civil offence with a fine. ( In all the cases I've seen. )

Helpful Google Search: transporting nuisance animals off property

Excellent post! I built a very similar trap years ago based on some plans in the Foxfire series of books. We had a significant skunk problem and I needed a way to deal with them in a humane manner. The difference in design was that mine was solid with a small opening for air. I didn't know it at the time but I did myself, and everyone else, a big favor by not having screened sides. I've never seen anything official to back me up, but it seems if the skunk can't see you when it point's the sprayer in your direction, it won't spray.
I captured over a dozen skunks (and numerous raccoons) and never once did I get sprayed. I think the screened sides make us feel better as humans but in all honesty, most of these animals live in very tight, confined, dark spaces. Seeing a human walk up to your cage I'm sure is a freaky experience...

In my case the screened sides serve two purposes, neither of which was 'makes me feel better':
1- It is my understanding that most animals assume that anything they can see through is not a true barrier (like say some leaves, or ivy, something to be pushed through, not an impregnable wall), as a result having a clear screen at the back and sides makes the animal unable to perceive that they are walking into a box with potentially no escape (burrowing animals have no problem with this, but others do). Next, I don't want to get right up to the trap to confirm that there is actually an animal inside it, or if it was just falsely triggered, so being able to visually confirm from a distance saves me some effort.

2- This was absolutely a 'build with what I have laying around' project, I happened to have a fair amount of heavy duty screen mesh that I used in a firepit project (which I really should have taken pictures of) laying around and doing nothing. Now its part of a very effective trap that will likely be serviceable for a while.