If you build it... they will come! The Bee houses come to life.

Carefully cut leaves to put into the nest, these will be filled with pollen and then a tiny egg laid in each one. several of these leaf nests will fill just one hole with the females being laid first then the males towards the outer edge of the tunnel. This will allow the males to hatch first and get ready for the later females to emerge. The males will hang around the nesting area and mate with the females once they emerge a couple of weeks later.
Making these bee houses I drilled a 10mm hole for the Mason bees and a slightly larger 12mm hole for the leafcutters. It's really rewarding to see them using their allotted holes.

 A chunky leafcutter bee, she has been working hard gnawing at the holes to make them the right size inside and then carrying cut leaves to put in them. Rose bushes are a favourite for these little queens.

A Leaf cutter bee has completely filled one of the top holes with her little leaf cells in which her grubs will grow.

 There seems to be a lot of debris below, spare rejected leaves and a lot of saw dust where the bee has gnawed the inside tube to fit her needs.

Rejected leaves and sawdust from altered holes.You can clearly see here the difference in hole sizes for the different bees, the larger ones being for the Leafcutters.

Each hole has to be at least five inches deep to allow a good mix of female and male eggs. If the holes are too shallow, only females will be laid.

Here we can see a smaller Mason bee putting the finishing touches her smaller chamber. It is being filled with pollen, once this is done an egg will be laid and then it will be sealed up with mud, hence the name 'Mason' bee. I have put a tray of mud below the logs to provide the tiny bees with an easy source of mud.

This lovely picture was taken a couple of months ago and shows the first bees to arrive at the bee houses...the red mason bee. These bees were the first to arrive and just seemed to be biding their time and sleeping in the holes, I imagine they were the newly hatched males waiting for the females to hatch and become available.

In the early morning the tiny Mason bees would stick their heads out of the tunnels and warm themselves in the morning sun. This is an important fact and all nest sites should be placed so they catch the early morning sun, facing the East. This allows the tiny critters to power up for the very busy day ahead.