A male Cerceris sp. looking for a sleeping spot on the bee hotel. I hadn’t seen this genus yet on the bee hotel so this is nice. Here he is still checking nest holes for a suitable spot, but after a little time he entered one of them.
I suspect it to be C. arenarius. The wasp reappeared on numerous occasion afterwards, so I’ll try to get some better photographs for identification.
References1 Nederlands Soortenregister