What a great image.  Thank  you!

How lucky can a person get! You spotted one of the many native solitary pollinators. It is a wool carder bee, Anthidium manicatum, blocking the entry to a hole/space which contains the individual cells she built and provisioned for her eggs which will soon hatch. Next spring, a new generation of adult wool carder bees will emerge.

A friend who studies several common native bee species here in Oregon, has seen some wool carder females create a debris pile similar to that in an apparent effort to seal off and hide their nest.

The typical place for a wool carder bee to build a nest is a hollow tube, such as a dead plant stem. There, she’ll construct individual cells, each one designed to hold one egg on a pollen cake which will be the youngster’s only food source until it matures and emerges from the cell next year. The individual cells are wrapped in soft “wool” removed from fuzzy leaves such as lamb’s ears, Stachys byzantina.

Information and images about the wool carder bee are here, including a row of cells wrapped in wool (3rd image from the right): http://www.bugguide.net/node/view/7744.