The great beaver migration has started! Thousands and thousands of beavers across northern Minnesota have left their families and embarked on a perilous journey through winding streams, across bogs, and sometimes over land in an effort to find hearth and home before ending up in the belly of a wolf. Ok, it is not technically a migration…more like a mass exodus of young beavers who are tired of living with their parents and family, and think the grass is greener if they set off on their own (i.e., dispersal). Typically this large dispersal event starts when the ice melts in spring and continues through early June. Beavers will still disperse at other times of the summer and fall but spring is peak dispersal time. And this is where the wolves come in. Many young dispersing beavers travel through dangerous places in hopes of finding a spot to dam up a stream and create a pond to call home. And by dangerous we mean places that lack deep water where beavers could escape an attacking wolf. Put differently: dispersing beavers often travel through habitats where they are toast if discovered by a wolf (or other predator like bears). Unsurprisingly, wolves take advantage of the large increase in vulnerable beavers, and wolves kill the most beavers of any month in May. Based on ~2,500 wolf scats we collected and analyzed in 2015, we estimated that beavers constituted 60% of wolf diets in May. Of course, there is variability in predation behavior between packs and beavers constituted up to 87% of some pack's diets during May. That said, in years with mild winters, such as this year, predation on beavers can be quite high in April. Last year, when we had a super long winter, predation on beavers in April was virtually nonexistent. Most of the beaver kills we find at this time of year are in flooded ash swamps, soggy black spruce bogs, beside narrow and shallow woodland creeks, and sometimes just in the woods far from water. And the predation on beavers has already started this year, and we have documented 7 dispersing beavers killed by wolves thus far (we started our predation work on April 15). For instance, we have studied the predation behavior of Wolf Y1T, the breeding male of the Blood Moon Pack, from April 15-21 so far. During this period, he has killed 3 dispersing beavers and after each kill went right back to the pack’s den, almost certainly to provision his mate and therefore his pups. In some sense, the scene in April-May is like a prolonged version of one of those nature documentaries where the baby turtles have hatched en masse and are trying to get to the sea before birds and other predators pick them off. Except in this instance, instead of a beach, beavers are navigating a tangled interconnected web of wetlands and streams and ponds that perforate an expansive forest that is home to dense wolf population that are looking for an easy meal so they can survive and rear their pups. The beavers’ goal is to find a home and a mate. Some will make it. Some will not. Sources used for this post: 1.) Gable et al. 2017. The problems with pooling poop: confronting sampling method biases in wolf diet studies. Canadian Journal of Zoology. 2.) Gable et al. 2020. Outsized effect of predation: wolves alter wetland creation and recolonization by killing ecosystem engineers. Science Advances. 3.) Gable et al. 2023. Wolf-beaver dynamics in the Greater Voyageurs Ecosystem, Minnesota. Book chapter in Wolf: Nature, Culture, Heritage.