Spring has sprung early this year, but does that mean hibernating bears will get out and about sooner than usual? And what about other hibernators? WTIPs Jay Andersen talks with a local naturalist about how the weather affects or doesn’t affect, bears, chipmunks and mice.
Chel Anderson is a botanist and plant ecologist for the Minnesota Department of Natural Resources. She lives here in Cook County and joins us periodically to talk about phenology or what’s going on in the woods right now. So, welcome Chel.
Anderson: Hello, Jay.
Well, has this very early spring had any impact on hibernating creatures? Let’s first talk about bears.
Anderson: Well, that’s a great question. I think it’s best to start with thinking about ok, bears have been living here for thousands of years and this isn’t the first early spring. So, I have a lot of faith that there’s a lot of resilience built into the bears’ hibernating system. But, it’s still interesting to think about and wonder at, well, how do they manage these things? We’ve talked about how cubs are born in the den, during the winter, during the mother’s hibernation. The moms are going to make all the decisions here. The cubs are far from on their own, so the moms are going to decide are they ready to go out yet or not depending on what the weather is. She’ll just keep them right there in the den or maybe move them even to a better spot, another alternative den, if that seems reasonable. They are very good mothers and I suspect that they’re used to bringing their cubs through kind type of thing. For the other bears that don’t have responsibilities for cubs, whether they are males or females, they could well be out touring around a little bit, looking for opportunities to tie into something to eat. Remember, their digestive systems have been very, I guess, cleaned out is a good way to say it, because they haven’t been doing any eating, right? They’ve been kind of specially prepared physiologically for hibernation, so they have to slowly come back to kind of normal digestion and normal eating. So, they have very simple diets at this time of year. I would say probably the biggest effect on the bears who might be out moving around looking for something to eat by now, even if they’re going back and napping a little bit in their dens, is that because we haven’t had any rain, there isn’t a lot of green up of fresh grass shoots and sedge shoots and things like that, so those aren’t real available yet to eat, and that would be a key early food for bears.
It always seems to me, whether it’s an early spring or not, that bears tend come out just a couple three weeks a little too soon.
Anderson: Yeah, well, they probably do. Maybe they’re anxious, I don’t know, or maybe we’re not quick enough to get everything put away, so that we’re not attracting them.
Well, it just doesn’t seem to me that there’s anything much to eat, but then again, I’m not looking at the same goodies that they might. What would be some of the first things? You mentioned grass shoots.
Anderson: Yep, grass and sedge shoots are important. So, fresh shoots of simple things, not woody things, but herbaceous plants, especially grasses and sedges. They also eat the flowers of the aspen, so you might see a bear pulling over a sapling of an aspen to get at the flowers that are out, and there are some aspens that are beginning to flower, not a lot yet, but they’re happening.
So that would be much the same as what they will do later in the year when they are berries to pull down? You see all those branches that have been brought down.
Anderson: Right. Exactly. Another thing that you might see evidence of is you’ll see ant mounds dug up this time of year, because the ant larvae are a good first food often available. Sometimes you’ll see rocks turned over. Bears go around and turn over rocks looking for the larvae of other insects that they can eat. So, those are some of the first and usually available foods right away, but they’re not super abundant yet in part, because as I said, there isn’t a lot of green up of those grassy shoots yet, and we don’t have a lot of aspens in flower quite yet.
What about other hibernators, like chipmunks?
Anderson: Well, you know, for other hibernators, it’s kind of a mixed bag, I think. If you went into the winter in good condition to spend a winter, then you’ve still got some fat reserves to go. So, the fact that there isn’t maybe a lot of favorite foods out quite yet is probably not a big deal, you can probably make do. If you went into the winter not in very good condition, it could kind of play either way. Maybe it’s great that you can get up and start looking for something to eat, because there are fresh shoots of a few things out there that chipmunks would be interested in and they’ll certainly be looking for any seeds that all the other critters that were active during the winter didn’t get. As we’ve talked about for with the amphibians and reptiles, they’re good to go whenever they wake up. As long as the ponds and rivers and lakes are not frozen anymore, they can just start right in on their breeding. There’s plenty of aquatic insects and things that they are using to live on. I can say for sure, though, that some things aren’t up yet. Just this past weekend, I got to see two different nests of jumping mice, where those little mice, those dear little mice, were still coiled up in this perfect little ball with their four-inch tails wrapped right around them, and their big hind feet squeezed up tight to their abdomens, still sound asleep, completely asleep.
Chel Anderson, DNR botanist and plant ecologist. Thanks for helping us understand what’s going on around us this spring.
Anderson: Always a pleasure. Thank you.