If a wolf pack was in a situation where food was scarce and relocating was not an option, would they resort to foraging plants or fruit?

Which plants would be toxic to wolves if ingested?

Would they know by instinct not to eat these plants?

I apologize for asking three questions in one. I'm a children's book author, working on a story about a pack of wolves. Can you help me?

Thanks for your time! :D

Wolves, like foxes and dogs, can and do eat vegetable matter, though not very much.  A study in Italy on wolf diet in Mediterranean, Apennine and Alpine habitats all showed vegetable matter to make up less than 5% of the wolf packs' diets (Capitani et al. 2004 Mammalian Biology vol 69 pages 1-10).  Canids (dogs and allies) generally are pretty omnivorous and while meat is the main source of food they will take all sorts - I've seen foxes eating blackberries and taking beetles.  Depends on where your fictional wolf pack was as to what was toxic, but I'd guess that they would be pretty good at avoiding toxic foods, either through learning from other pack members whilst young and through taste.  Canids can (and are) poisoned routinely, but usually through the use of poisons that are hard to detect or which are masked by other smells - remember that canids are used by drug squads and rescue organisations in airports and disaster areas respectively to find contraband or people through smell!