wonderful pictures and thank you Konrad. I'm going to look more closely at my bees this season and see what different pollens I see. How does learn what pollen is from what plant? I imagine if willows are the predominant tree in bloom, it would be a good guess. But what about when plant bloom is more varied?

Here`s a link. Here is a link that might be useful: Bees

It's been now several years since I started making houses, ..overall, I'm not too pleased with the results. Just a little disappointed that not more bumbles use this home. I have also tried with several clay pots dug a little into the ground, laid down sideways, never one's a bumble nested. One of my owl houses was occupied by them one year, took some pictures at the end of season, [low number of bees]. I know that bumbles like moss, have seen many bumble nest in the ground,..as a child in Switzerland, on a hill/shade side was mostly moss, I could find many nest there. I might just fill the houses with moss and see, have build another 5 and I will place the entrance holes on different spots, perhaps paint with yellow around the hole. This house is about 16 feet up on a tree, pretty shady in the bush. Never had owls but Northern flying squirrel were in it one time, perhaps they got the moss inside? .. Please share your experience with attracting bumbles to your home. Allot of natural habitat gets destroyed by man, hopefully we can help a little.

I have hundreds of these bees on my caryopteris and other flowers. Where do they live? In a hive, in my house, in the ground? I see them sleeping at night right on the flowers.