Native mushrooms play an important, though often underestimated, role in deer, elk, and caribou diets in North America. Mushrooms are often noted as an unusual or anomalous food in the diets of cervids; yet they often dominate diets in the late summer and fall in forested areas of western North America and throughout the year in the southeastern U.S. Mushrooms are particularly high in protein (16–19%), phosphorus (average 0.75%), and potassium (average 2%). Also, mushroom production is generally greatest in fall. Therefore, they are a highly nutritious food in late season when other native forages may marginally meet basal nutrient requirements of ungulates.
Launchbaugh, Karen L. and Urness, Philip J.
"Mushroom consumption (mycophagy) by North American cervids,"
Great Basin Naturalist: Vol. 52
, Article 5.
Available at: http://scholarsarchive.byu.edu/gbn/vol52/iss4/5