WSU has a pdf with general care, and describes the stages (month by month) for mason bees.
Orchard Mason Bees (WSU Extension King County Hort Fact Sheet #83)
http://www.metrokc.gov/dchs/csd/wsu-ce/agriculture/PDFs/MasonBee.pdf

Here is a link that might be useful: Mason Bes (WSU)

I live out by Seatc airport, nicsbees, and I didn't do anything with mine over the winter and they seemed fine and I have a lot more closed holes than I had last year. Mine are on the west side in the afternoon sun. I like watching their activaties when I come home from work.

I am really excited to read about your bees. This year I'd love to make my own bee houses. Is it difficult? And then, do you have to buy the cardboard inserts? And, bees? Do you have to buy those as well, or as they say "build it and they'll come"? Please tell me about your personal experiences. Thanks a lot

The WSU link did not work for me. Try this search at WSU for information.

http://www.googlesyndicatedsearch.com/u/washingtonstateuniversity?q=Orchard+Mason+Bees

Terran

Here is a link that might be useful: WSU Orchard Mason Bees

The WSU link for fact sheet #83 must have changed. Here it is: http://king.wsu.edu/foodandfarms/documents/MasonBee.pdf

Flora2, the paper straws are optional but make it easier to keep the houses clean from year to year. I bought my straws for this year (my first) but then saw that some people make them out of baking parchment. I have seen houses made of blocks of wood, including chunks of tree trunk, with 5/16" holes drilled in them. Also metal cans or wood boxes with bundles of straws inside. I made mine out of a 2x4 but I think the holes are too short so I'll make a deeper one next year. I bought bee cocoons but many people just put out houses and the bees appear! I may try that in another location.