A bee that likes mud

This little bee is larger than a sweat-bee and smaller than a honeybee. It is a native North American bee that lives mostly unnoticed in the American landscape.

Known as the mason bee, this insect builds a nest of mud. It finds a crack in a rock, a hole in a board drilled out by a carpenter bee or a hollow, broken weed stem in which to make a nest. The mason bee begins the nest by packing a small amount of mud into the hole. Half done, the bee collects pollen from flowers. It makes a soft bed of pollen upon which it lays one egg. After the egg is laid, the mason bee seals the hole with more mud and proceeds to busy itself doing more masonry work.

I found this bee packing mud in the end of a hollow length of metal used to make an ornate gate. This bee is a great pollinator.