Fluctuations in food availability often create corresponding variations in marten populations. This condition is more pronounced in the less optimum habitat of the marten. Probably the second most critical food source is berries, especially blueberries, followed by small birds, eggs, and vegetation. The marten is a voracious and opportunistic feeder. Carrion such as the remains of wolf kills or salmon carcasses are eaten in many areas.
Wild marten are fond of sweets such as jam.
They will sometimes take treats from humans. It has been reported that red squirrels are a major food source for marten. This does not seem to be the case in Alaska. In fact, the two seem to get along quite well. Marten commonly use red squirrel middens as resting places.