While one thinks of Coyotes as opportunistic eaters of fruit, it is a whole other thing to "digest" the fact that Wolves do the same............Deer, Caribou, Bison, Moose and Beaver are the prey items that most of think of when you investigate the Wolf diet..............."Wolves almost certainly cannot digest berries as efficiently as they can digest ungulate prey (Litvaitis and Mautz 1976)."............ "However, even if digestibility of berries is low, great abundance of berries on the landscape might make berries an important food source because berries can be acquired with little energy expenditure in the summer months when availability of mammalian prey is low (Tremblay et al. 2001)"................. "In Voyageurs National Park, Minnesota, berries constituted 30–50% (volume) of wolf diets in July and August 2015 (T. D. Gable, personal observation)".

https://www.researchgate.net/publication/313515430_Estimating_biomass_of_berries_consumed_by_gray_wolves

Estimating biomass of berries consumed by gray wolves 

Article in Wildlife Society Bulletin · February 2017

 THOMAS D. GABLE,1 Northern Michigan University, Department of Biology, 1401 Presque Isle Avenue, Marquette, MI 49855, USA STEVE K. WINDELS, Voyageurs National Park, 360 Highway 11 E, International Falls, MN 56649, USA JOHN G. BRUGGINK, Northern Michigan University, Department of Biology, 1401 Presque Isle Avenue, Marquette, MI 49855, USA 

ABSTRACT 

Gray wolves (Canis lupus) consume berries and other wild fruits seasonally when available or abundant. However, a method to convert percent frequency of occurrence or percent volume of berries in wolf scats to percent biomass has not yet been developed.

We used estimates of the average number of blueberry (Vaccinium spp.) seeds in 10 individual wolf scats collected in and adjacent to Voyageurs National Park, Minnesota, USA, along with published values of the number of seeds per blueberry and blueberry masses to estimate that a wolf scat containing only berries equated to an average of 0.468 kg of berries consumed.

In Voyageurs National Park, Minnesota, berries constituted 30–50% (volume) of wolf diets in July and August 2015 (T. D. Gable, personal observation).

We recommend using this berry conversion factor (0.468 kg/scat) to convert the percent frequency of occurrence or percent volume of berries and other wild fruits to percent biomass when estimating wolf diets from scats.

Wolves are opportunists, however, and will take advantage of other food sources such as human garbage, flightless molting birds, and spawning salmon (Oncorhynchus spp.) when available (Szepanski et al. 1999, Peterson and Ciucci 2003, Wiebe et al. 2009). 

Wolves also consume fruits such as wild blueberries (Vaccinium spp.) and raspberries (Rubus spp.) when these fruits are abundant. In areas where berry consumption occurs, berries typically constitute a minor (

However, in some areas, berries can be a significant summer food item for wolves. Berries (primarily blueberries) constituted 10–30% (frequency) of the diet of wolves from 1 June to 15 September in southern Quebec, Canada (Tremblay et al. 2001). 

Similarly, vegetation (primarily berries) occurred in 52% of scats collected at home sites in July and 20% of scats collected on trails in August and September in north-central Minnesota, USA (Fuller 1989). 

In Voyageurs National Park, Minnesota, berries constituted 30–50% (volume) of wolf diets in July and August 2015 (T. D. Gable, personal observation).