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Roof Rat

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Rats are eating my trees!  The back field is currently experiencing an infestation of rats.  The rats aren't eating the coffee directly.  Instead, they climb up to the tops of the trees and chew on the branches.  This causes the chewed branch to fall over and die, along with all the leaves and coffee cherries on the branch.  Stupid rats.  If they ate the entire branch then they wouldn't cause nearly as much damage but they eat just a small portion of a branch, just enough to kill it, then move on to the next branch.  It's as if they're purposely trying to cause as much damage as they can.

Poison I first noticed the damage a couple months ago while pruning.  At the time I was busy doing other things and the rat damage was only in a small area of the orchard so I ignored the problem.  A few weeks ago I finally got tired of seeing the rats destroy branch after branch, all loaded with healthy coffee.  I talked to several other farmers.  Poison seems to be the preferred countermeasure.

Rats are skittish and smart.  Especially the roof rats (ratus ratus) out in my field.  Anything new in their environment and they'll ignore it for several days.  If a trap or poison hurts or scares them instead of killing them instantly, then they quickly learn to avoid it.  The poison I purchased is an anticoagulant containing 0.005% diphacinone.  One small dose won't hurt the rat.  If it did, then they'd take a nibble, get sick, and learn to avoid the bait (i.e. become "bait shy").  Since this poison is 99.995% peanut butter and bird seed, the rats learn to like it.  Rats live a very rough and tumble life.  They're always getting scrapes, bumps and bruises.  When enough of the anticoagulant from the bait builds up in the rat's system, they can't stop bleeding and all the bumps and bruises become fatal.  The rats never figure out what went wrong.  At least that's the theory.

PVC traps Bait The first problem is that rat poison works on just about anything that eats it.  Since I don't want to poison birds, dogs, children or anything else that might be out in the field, I used PVC to make little holders for the poison.  The concept is that only a rat can fit inside the PVC to reach the poison.  I placed several of these PVC bait traps all around the orchard.  I placed some on the ground, some at about mid-height on the trunk, and others way up high in the trees where all the damage is occurring.  I wanted to see which positioning was the most effective.

The answer:  the rats seem to ignore the poison no matter where I place it.  Stupid rats!  It's yummy peanut butter!  Eat it!  Everybody knows that rats are supposed to like peanut butter!  Apparently Hawaiian rats are too smart for that trick.

Mongoose The rats did eat some of the poison after a couple days, but only very small quantities.  The stuff at ground level was eaten the most.  Unfortunately, anything left at ground level can also be eaten by a mongoose instead of a rat.  In the 1883, the Small Indian Mongoose (herpestes auropunctatus) was introduced to Hawaii in an attempt to control the spiraling rat population.  The moron that introduced the mongoose didn't count on the fact that rats are nocturnal (active at night) while mongooses are diurnal (hunt during the day).  The mongoose population has hurt the native Hawaiian birds more than the rats.

Barn Owl Hawaii also has a healthy population of barn owls (tyto alba).  I plan to build lots of barn owl houses.  Barn owls are the ultimate rat predator.  They won't eat the rat population to extinction (they would starve if they did) but they will help keep the rat population under control.  The problem with barn owls is that they don't hunt near their nest.  It's a defensive thing.  They don't want to attract predators back to their nest so they fly up to three miles away to do their hunting.  I can build lots of barn owl houses but that will help the neighbors more than it will help me.

I may try to get the neighbors to put up their own barn owl houses.  I'll have to give them the owl house because buying a pre-built owl house can cost $100.  Ridiculous!  Barn owls will nest in just about any cavity that is big enough for them.  The perfect barn owl house is about 2 feet on each side with a six inch entrance hole.  That's about the same dimensions as a cat litter box with a lid, which I can buy for only $20.  I may have a difficult time convincing the neighbors to hang cat litter boxes on their barn.  So I'll probably use the wood from some old shipping pallets to build some prettier barn houses and save the cat litter boxes for the back of my own barn where nobody will see them.

Owls are cool but I need a solution now.  I went back to the Internet for more research.  Here's a site with great pictures and an identification quiz.  I even found a rat killing message board complete with web cams.  Did you know there's a sport called rat fishing?  My father is a dedicated fly fisherman, maybe I can convince him to spend some time in my back field at night.

Bucket Trap In Zimbabwe, some farmers will bury buckets or large pots with a couple inches of water in the bottom.  Then they hang a piece of corn on a wire across the top of the bucket.  Rats are excellent climbers and have no problem running along a wire but apparently they fall right off a spinning piece of corn.  One farmer claimed to catch 934 rats with 9 traps in 21 days.  That's a lot of rats.

Tree Trap I don't have any corn handy, nor do I have a good fishing rod.  Instead, I went to Home Depot and bought every rat trap they had.  They only had eight so I bought a bunch of smaller mouse traps too.  Everybody is familiar with the typical mouse spring trap.  Well, a rat trap is exactly the same only much larger and stronger.  A mouse trap will really hurt if it accidentally catches one of your fingers.  A rat trap can break a finger if you're not careful.  Sure enough, while setting one of the large rat traps, it went off and caught my thumb.  Let me tell you, IT HURT!  After several minutes of swearing, I tried to ignore the pain and get back to work but later that night it really started to throb.  I ended up going to the emergency room to have them drain my thumbnail so it wouldn't pop off.  We don't have health insurance yet (don't get me started on that subject) so I wanted to drill a hole in my thumbnail myself.  Valerie wouldn't let me.  It was midnight and the only place open was the local hospital.  They lanced my thumb and gave me a tetanus shot.  I was in and out in under an hour.  Still, I'm afraid to know what the hospital bill will be.

I had mounted all the spring traps inside wire cages I made to help keep the birds and dogs safe.  Then I tied the cage in the trees.  The next morning, not a single trap had been triggered.  Stupid rats.

I won't quit!  They can't beat me!  I'm smarter than a rat and I'm going to prove it!  It may take me awhile but I'll figure this thing out.  I still have nine good fingers left.

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