# Thoughts on Robbing Screens



## reprosser (Mar 16, 2013)

"Intuitive behaviors are interesting. Potential robber bees leave from their original colony
by going over the robber screen,but don’t do the same when they try to enter a neighboring hive.
They hover around the fronts of screened hives and never get in; then,they
go back home over the top of their own screen. We aren’t sure, but it appears that
these robber screens also deter marauding yellow jackets"

from http://entomology.ucdavis.edu/files/147611.pdf

I just added robber screens to my 4 hives (I plan to leave them on permanently) to see how well they work.


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## David LaFerney (Jan 14, 2009)

Not much if any - although intuitively you would think so. There was a university study on robber screens that made this same observation - not a research result, but an observation - reprosser seems to have found it. However, it does appear to me that the farther the opening into the hive is from the opening into the robber screen the better they work. I'm a believer though - I have them on just about every hive now.

We have chickens as well as bees, and sometimes we let them out of their wire enclosure - even they can get really confused about how to get back in and they are much more intelligent than individual bees. They get in a spot where they are very close to where they want to go (inside of the pen) such as behind the open door, but to get in they have to actually move farther away to go around something (like the door) to get to the opening, and they just can't picture it. They really want to get in by the short straight line distance - but the wire keeps them from it. 

I've noticed people exhibiting the same kind of behavior - climbing over or squeezing through a fence instead of simply walking a short distance around it for example. Although that's probably mostly just laziness.


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## Slow Modem (Oct 6, 2011)

I have a robbing screen on one of my hives that was weak. They work ok, but when there's a lot of traffic, things get really crowded on the screen. I don't know if they're able to pass pollen or nectar through the screen, or if they have to wait on an opening in the top to get into the hive.


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## Becky Jackson (Jun 7, 2013)

I seem to be the only one who has experienced that the robber screens DON'T work in all cases. I built the ones as per UC Davis and Eric Mussen's plans. I had some newly started nucs with caged queens still, which started being robbed on day one of making them up. I made up robbing screens but they were not effective since the robbing had already begun. The bees just flew or crawled up and over in massive numbers. I used sheets draped over the hives to cover just to the top of the robber screen, and that helped (left them on for a week or so). Time and perseverance got it under control. On another late nuc I had to feed it, and the robbing just wouldn't quit until I gave them some more brood and frames of honey and took the upper feed tray away. It had a robber screen in place the whole time. All my hives now have screens, and they will stay on to keep robbing from ever happening.

So what I'm saying is that if robbing has already begun, simply adding a robber screen may not be enough to protect your hive. You may have to combine several anti-theft techniques.
Becky


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## David LaFerney (Jan 14, 2009)

You aren't the only one who has had that experience. Robber screens are just one tool. They help a lot, but you still have to cover all the bases.


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## JimmyA (Jul 22, 2013)

I have pretty good luck with robber screens. I have 2 nucs and needed to use them (robber screens) as my nucs are not full -- just a few frames. They really help with robbing. I think I got them from Mann Lake. I had to modify them -- shorten them for my hive. I recommend them. They work for me.

JimmyA


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## Michael Bush (Aug 2, 2002)

> if you are using robbing screens on say 2-3 hives in the same area, will the bees from the other hives not know how to enter similiar hives and still rob them -- since they have to go in from the top to enter their own hives?? Is this an issue or not? 

Not. The mentality of a bee returning home is not the same thought processes as a robber.

>Also is the width of the opening and issue? 

Somewhat. UC Davis seems to think it's not. I think it is...


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## Belewsboy (Jun 6, 2012)

I had a new nuc which was constantly being robbed by large numbers of robbers. I saw a recent post on a homemade design. Mine is about 5" tall and full width of the bottom board. I put a reducer in the hive entrance with the smallest opening which is offset to one side of the hive. I put the same size opening on top of the screen on the opposite side of the hive. The robbers smell the honey from one side of the hive...far away from the screen's actual entrance. Works every time. I am still amazed how well this works.


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## David LaFerney (Jan 14, 2009)

Slow Modem said:


> I have a robbing screen on one of my hives that was weak. They work ok, but when there's a lot of traffic, things get really crowded on the screen. I don't know if they're able to pass pollen or nectar through the screen, or if they have to wait on an opening in the top to get into the hive.


You know after I read your remark I got to thinking about it, and went out to my apiary where I have about 25 hives with assorted variations of home brewed robber screens that I made to evaluate the differences. Some of them have metal window screen wire on them (which I thought might help to deter SHB) and others have hardware cloth up to #7. Of course we have a nice goldenrod flow going right now so lots of hive activity. Sure enoughmost of the ones with the bigger holes had a lot of bees hanging out on the outside of the screen, and the ones with the screen wire did not - it looks to me like they actually might be passing nectar through the bigger holes in the hardware cloth, and the screen wire deters them.

BTW, it's hard to quantify, but I believe that they all work pretty well unless a hive is really really vulnerable for some reason - such as teetering on the edge of crashing from mites and associated sickness. However it really does seem that the more elaborate variations - staggered/reduced entrances, and metal masking on the end where the entrance to the screen is - actually do work better. That's my impression from trying them for this one season anyway.


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## kilnrat (Feb 10, 2010)

Thanks for your imput. It's good to hear other's experiences.


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## kilnrat (Feb 10, 2010)

Thanks for your input. It's always good to hear from other beekeepers.


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## kilnrat (Feb 10, 2010)

Thanks for your input. It's always good to hear other's experiences.


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## Glen H (Aug 17, 2013)

This is what I have been using, it has a propolis screen on it.

It appears to me that they pass stuff from the outside to the inside through the screen.








Glen


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## kilnrat (Feb 10, 2010)

Thanks for your input. Always good to hear from other beekeepers.


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## Slow Modem (Oct 6, 2011)

That's some great feedback! Thanks guys!


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## Slow Modem (Oct 6, 2011)

Since I was out in the bee yard this morning, I went ahead and put robber screens on the rest of the hives (not the greatest paint job, but it works). I figure it's like taking Vitamin C - It might not help, but it probably won't hurt.


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## JimmyA (Jul 22, 2013)

I think you'll be pleased with the results.


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## JimmyA (Jul 22, 2013)

Looks like Pacasio to me!


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## Glen H (Aug 17, 2013)

I like that it has three doors (entrances) on it. Mine just has the one on the top.

Glen


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## JimmyA (Jul 22, 2013)

Mine, for a Nuc, has a door on top and a door on the bottom.


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## Slow Modem (Oct 6, 2011)

Glen H said:


> I like that it has three doors (entrances) on it. Mine just has the one on the top.
> 
> Glen


The 10-frame has two lower doors, the 8-frames have one lower door and one top door.


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