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Daily Archives: January 12, 2011

These photos are bringing back some great memories of my time on the ‘farm’ with mason bees. 

We tested various types of nests, and to duplicate these, I bought 50 small office garbage cans. 

A set up used in a mason bee trial
in blueberry field.

I set each one on  top of a fence posts. 

Unfortunately, bears could not resist going after the small amount of  pollen inside the nesting tunnels.  Several of the containers were smashed to pieces. 




Mason bee trial in a blueberry field.  Bears smashed quite a few of the containers with mason bee nests.  In the distance two other containers are visible sitting on top of a post.

  After this, I realized that bears were one of the challenges for keeping mason bees in these fields.  I knew that bears go after honey bee hives, and yes, beekeepers kept their hives surrounded by electric fences.  But I did not think that bears would go after mason bee nests.  I guess early spring bears are hungry and anything goes. 

In photos of previous posts, you can see the electric fence surrounding the nests.  It is easier to have many nests surrounded by one electric fence,  than having numerous locations each with an electric fence.   



Large mason bee nesting area surrounded by
an electric fence.



But concentrating mason bees in one area begs the question about the distance that mason bees fly.  This of course will determine the distance between mason bee houses/set-ups.  Another factor for consideration is flower density.  Distances flown will depend on flower density.  The question I find most intriguing is whether the female to male ratio changes depending on the number of cocoons set out at any one location.  If you set out say 1000 cocoons will these produce more females then when you set up 20,000 cocoons?  A good PhD project for someone.

Steve E from California, contacted me about setting out mason bees in an almond orchard.  He asked me for feedback on his idea of constructing a housing unit for mason bees out of a plastic barrel.

” I brought the two plastic tubs into my garage and took this photo of the 2 containers side by side.  You can see that the all-blue barrel is uncut, while the white one has a cut-out door of about 12″ x 16″ bordered by black tape.  Within the barrel are stacked cinder blocks.  You can make out a roll of cardboard tubes within one cinder block.  On top of the cinder blocks is a wood bee block.

So, if these barrels are only 33 inches tall (a bit less than one meter), are they too short to be effective ?  The diameters are 23″.  I could put a stack of cinder blocks out with a wood pallet on top, and elevate the barrel on the pallet to gain some height.  But that would make it more vulnerable to the wind, as well as more work and materials for multiple sites.
I can obtain these barrels quite easily, and they are simple to cut out.  The temperature within vs. without is at least 5 degrees warmer on a sunny day.  On an overcast day, at least the blocks are protected from the wind.
I can put vent holes in the top or upper edges.  But these are targeting February and March activity in an almond orchard and plum orchard, and it is generally lower to mid 50′s F in those months.
Please comment on the potential efficacy of this simple housing unit.”
COMMENTS:  The bees may behave/forage/fly differently in the blue and white unit.  Setting them side by side would make for an interesting test.  Cut a hole in the center of the top (4-6″ diam) so excessive heat can escape.  Also disoriented bees can fly out through the top and re-orient to their nesting tunnel after flying through the door.  Set cinder block against the sides, so to avoid any rain coming through the skylight hole and falling onto the nesting tubes.  Secure  from wind.  Set out in an open and sunny location.   Set up 3 thermometers: 2 inside at different heights and one on the outside north wall for comparison.  I look forward to hearing more about this housing unit.
When I started  producing mason bees, I set the mason bee houses onto a barn and shed of a blueberry farm.  This was easy.  But the farmer also wanted mason bees in his blueberry field to make sure the mason bees were pollinating his blueberry flowers far from his home and barn.  But there are usually no buildings out in these commercial fields for setting out mason bee houses.
Mason bee cocoons and their nests require a few basic essentials.  They need to stay dry and during the day need to be warm- in other words, a dry spot, in the sun and preferably out of cooling winds.
I came up with using Garbage pails, set up on its side.  Theywere secured to a post and with a few other pieces of  lath, secured to the post because some of these places can be quite windy.  It worked rather well.  The set up time though was long because no field had the same type of post. 
Tim setting up a “Mason Bee house”.

Cardboard tubes were used at the time and bundles of these were set in the back of the container.  To help the bees orient to their nesting tunnel, cotton batten and “1″ foam was interspersed amongst the layers of nesting tubes.

The middle of the container was used the most by the bees.  On some days, under sunny conditions, it became very hot in the upper section of the container.  It looked like bees were avoiding the excessively hot area of tubes.  To ”cool it down a little, I cut a small hole in the upper part of the “roof” of the container.

There usually is a lip to a garbage container so that the lid can be fastened to the garbage pail.  Unfortunately, when the container was on its side, rain pooled in the rim drowning many bees.  I cut a drainage hole so that water would not pool in the rim.

The container was set up about 4 feet above the ground to avoid the splash zone and also to avoid the cooler ground temperatures.

When we started using routered nesting trays, these stacks did not fit very easily into the round container.

We learned a lot from this trial. 

The yurt was still a few years away!

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