I have 4 TBH's built to Dennis' specs all were working great I really like the design. I went on vacation from 6 Aug to 19 Aug. have been having a problem with yellow jacks. I did my first in-depth inspection today and found completly empty nests in two hives. I had my father-in-law feeding a 1:1 by volume suger water mix while I was away. I have a pan in the bottom of the hive that holds 1 liter of syrup, no problems here they were taking a liter a day. My intention was to get them to build more comb I was worried that they did not have enough to make it thru the winter. There was no new comb ever and they really never seemed to fill the comb they had. we have been having seasonable weather compared to the north east US. I did have a robbing problem and reduced the entrances down to about one inch wide. I also noticed the yellow jacks were able to go in and out with little resistance. These are Elgon bees, the Carns I have defend the hive to the end. Why did they abscond? and how do I get them to draw out more bars they average 9 per hive.