Bombus griseocollis foraging on Amsonia
Here is a selection of online and print resources for anyone interested in bees and other pollinators.

BeeSpotter. (Website).
https://beespotter.org/. (Citizen science site with bumblebee identification charts.)

Colla, S., Richardson, L., & Williams, P. (2011). (Online). Bumblebees of the Eastern United States. USDA Forest Service and Pollinator Partnership. 
(Photos, range maps and other useful information for identification.)

Eastern Bumblebees: Poster. (Online). US Forest Service.
https://www.fs.fed.us/wildflowers/features/posters/EasternBumblebeesPoster_reduced.pdf. (Good illustrations.)

Hansen, T. (2018). Buzz: The Nature and Necessity of Bees. New York: Basic Books. (A charming and extremely informative book by a naturalist that combines memoir and deep knowledge.)

Holm, H. (2017). Bees: An identification and Native Plant Forage Guide. MN: Pollination Press. (Clear, detailed guide to the families of bees and their preferred plants.)

Holm, H. (2014). Pollinators of Native Plants: Attract, Observe and Identify Pollinators and Beneficial Insects with Native Plants. MN: Pollination Press. (Great book for beginning and experienced native plant gardeners.)

Holm, H. Restoring the Landscape with Native Plants. (Blog). (Excellent photography and descriptions.) http://www.restoringthelandscape.com/ 

Illinois Wildflowers. (Website.) http://www.illinoiswildflowers.info/. (Photos, descriptions and fauna associations, including pollinators, of many species by Dr. John Hilty.) 

Lee-M├Ąder, E., Hopwood,J.,  Vaughan, M., Black, S.H., & Morandin, L. (2014). Farming with Native Beneficial Insects. North Adams, MA: Storey Publishing. (Useful for gardeners, as well as farmers.)

Mader, E., Shepherd, M., Vaughan, M., Black, S., & LeBuhn, G. (2011). Attracting Native Pollinators: Protecting North America's Bees and Butterflies. North Adams MA: Storey Publishing. (Great book for beginners.)

Moisset, B., & Buchman, S. (n.d.). Bee Basics: An Introduction to Our Native Bees. USDA Forest Service and Pollinator Partnership. (Nice, downloadable overview.) http://www.fs.fed.us/wildflowers/pollinators/documents/BeeBasics.pdf

Packer, L. (2010). Keeping the Bees: Why All Bees Are at Risk and What We Can Do to Save Them. Toronto: Harper Collins. (Engaging book by a well known entomologist.)

Schweitzer, D. F., Capuano, N. A., Young, B. E., & Colla, S. (2012). Conservation and Management of North American Bumblebees. USDA Forest Service and NaturServe. (Downloadable and useful for the more experienced.)

Wild Ones: Native Plants, Natural Landscapes. (Website.) (Native plant and landscaping society.) http://www.wildones.org/

Williams, P.H., Thorp, R.W., Richardson, L., & Colla, S. (2014). Bumblebees of North America: An Identification Guide. Princeton: Princeton University Press. (Excellent, detailed guide for the serious bee spotter.)

Xerces Society for Invertebrate Conservation. (Website). (Go-to resource for everyone.)
Articles and Papers (Online)

Insu Koh, Eric V. Lonsdorf et al. Modeling the status, trends, and impacts of wild bee abundance in the United States.  PNASPublished online 2015 Dec 22. doi: 10.1073/pnas.1517685113
PMCID: PMC4711882
PMID: 26699460

Jacobsen, Rowen. (7/24/2019). Are We Handling the Bee Crisis All Wrong?. (Online). Huffington Post. (Excellent overview of new research showing the value of native bees and how they help increase agricultural yields.) https://www.huffpost.com/entry/wild-bee-population_n_5d374e6fe4b004b6adb709d6

Hall, Damon M., Gerardo R. Camilo, et al. The city as a refuge for insect pollinators. Conservation Biology. First published: 14 September 2016. 

University of Minnesota Extension. MN lawmakers buzzing about $$ incentives for "Bee-Friendly" lawns. Yard and Garden News. April 19, 2019. (Includes resources for how to convert a regular lawn into a bee lawn.) https://blog-yard-garden-news.extension.umn.edu/2019/04/mn-lawmakers-buzzing-about-incentives.html