The diggerwasp hill project has delivered a first success: a female Crabro peltarius  has begun digging a nest. I observed her for two hours, between ±18:00-20:00.
In the period before she started digging she was inspecting the hill for a suitable spot and had a clear preference for dark shadow rich locations and underneath overhanging leafs. Possibly this is related with the solidness of the sand on those spots due to higher humidity?
Eventually she settled for a spot somewhat lower than the surface against the side of the hill where the sand is not contained by the stone wall.
She digs head first and emerges every 10 to 15 seconds to push out another load of sand. The sand is pushed out of the nest using the legs and will shove the sand using her abdomen when it has accumulated in front of the entrance. The animations show the use of her legs and abdomen while moving the sand.
I am happy that the hill works in principle and hope to follow the progress, but haven’t seen her after the initial observation. Possibly the sand is still too loose, although it has rained a lot during spring and I sprinkled the sand after installing the hill for a long period of time in order for it to settle?
Some bees seem to have dug nests as well but also the owners of those have not appeared yet. Also the earlier observed Lasioglossum bee did not finish her work. Another challenge is the local cat population, actually primarily our own cat, that lie around in the sand which we try to deter.
So, to be continued…. hopefully 🤞😅
References1 Nederlands Soortenregister