Why Most Squirrels Die Before They Are One Year Old

Added: 2026-05-23

[00:00:00]The squirrel you see in spring may never see the next spring. That sentence sounds dramatic, and I understand if it lands that way at first, but the longer I've spent watching backyard wildlife and reading what serious squirrel biologists have written, the more I've come to think it's just a quiet statement of fact. We have a habit, as people who live alongside squirrels, of treating their abundance as proof that they're thriving. They're on the fence, on the feeder, on the power line, on the roof, doing their small acrobatic work, and the natural human conclusion is that this animal must have figured life out.

[00:00:37]But abundance is not the same thing as ease. A species can be everywhere in your neighborhood and still be, at the level of the individual, living through one of the most precarious early lives of any small mammal you regularly see.

[00:00:52]The part that took me longest to understand is that what you're mostly looking at when you watch squirrels in a yard or park is the survivors. The ones that didn't make it are simply absent from the picture, and absence is the hardest [music] thing for a human eye to register. We count what's in front of us. We rarely count what should have been there. So, I want to try to walk through this carefully >> [music] >> because the story of why so many young squirrels do not see their second spring is not a tragedy story, >> [music] >> and I don't want to flatten it into one.

[00:01:26]It's more like an ecological pattern, the kind of thing that's been quietly shaping squirrel behavior for a very long time, and once you can see it, the small animal on your lawn starts to look like a different kind of creature. The first year of a squirrel's life is, by almost [music] any measure that wildlife biologists use, the most dangerous stretch it will ever go through. If a squirrel survives to its second year, its odds improve substantially because by then it has learned the local map, the local routes, the local risks. But getting to that second year is the hard part, and the reasons are not exotic.

[00:02:04]>> [music] >> They're the ordinary frictions of being small, inexperienced, and embedded in a landscape that did not design itself around your survival. It starts with the moment a young squirrel first leaves the drey, which is the leaf nest it's mother built somewhere up in a tree fork, often higher than people notice. A juvenile, meaning a young squirrel still learning the adult skills of finding food and reading risk, has none of the muscle memory the adults have. It hasn't yet built what biologists sometimes call a working spatial memory, >> [music] >> which is just the mental map an animal uses to remember where food is, where shelter is, and where the safe routes between them run. Adults move through a yard as if they're following lines you can't see, because in a sense they are.

[00:02:53]Juveniles are still drawing those lines for the first time, >> [music] >> and the cost of drawing them wrong, even once, can be high. The most obvious pressure is predation. Hawks, >> [music] >> owls, and a handful of ground predators all hunt squirrels, and a juvenile that hasn't yet learned to read a hawk's shadow, or to freeze against bark the instant a silhouette crosses the sun, is at a disadvantage that adults simply don't carry anymore. I'm wary of ranking which predator matters most, because the honest answer depends on where you live, what season it is, and what other prey is around. What I will say is that the behaviors you see in adult [music] squirrels, the long pauses on a fence rail, the head tilts, the quick checks of the sky, are not random ticks.

[00:03:42]>> [music] >> They are a kind of risk assessment, a constant background scan, and a juvenile is still learning the grammar of it.

[00:03:50]Then there are roads. This one is hard to talk about without sliding into the wrong tone. So, I'll just say it plainly. Vehicle collisions are a significant pressure on young squirrels, especially in suburban areas, >> [music] >> where their home range, meaning the area an animal regularly moves through, runs across a street. A young squirrel hasn't yet learned which crossings are tolerable and which [music] are not. It hasn't built the route habits that an older squirrel has. And [music] the cost of misjudging a car is final in a way that misjudging a hawk sometimes isn't, because at least with a hawk, you might dive into cover and live to be wiser tomorrow. The first winter is its own threshold. Squirrels don't truly hibernate in the way some people assume.

[00:04:37]They remain active most of the [music] year, and they rely on what biologists call scatter hoarding, which is the unglamorous term for hiding food in dozens of small caches across the landscape instead of one big stash. The whole system depends on the squirrel being able to find those caches again, sometimes weeks or months later, under leaves or snow, >> [music] >> and on having built up enough of a fat reserve through the heavy fall feeding period that biologists call hyperphagia.

[00:05:06]An adult [music] squirrel that has done this once or twice has an instinct for how much is enough. A juvenile is doing it for the first time, >> [music] >> often in a landscape it doesn't fully know yet, against competition from older squirrels who are also cashing and, in many cases, pilfering, which is the term for taking food another squirrel hid.

[00:05:29]Even before the cold arrives, the math of that first winter is already being decided. I think it's worth pausing here, because there's a temptation to picture this as a single dramatic struggle, and that's not quite right.

[00:05:42]It's more like a series of small daily decisions, each one small enough that none of them looks like much, but the cumulative weight of them is what the first year really is. A bad crossing, >> [music] >> a missed cash, a drey that didn't hold up in a storm, a few days of poor feeding >> [music] >> that thinned a fat reserve just enough to matter later. Most of the pressure on a young squirrel is quiet, and that's part of why we miss it. Then, you add the pressures that humans have introduced into the landscape, which a young squirrel has no evolutionary preparation for. Outdoor cats are one, >> [music] >> free-roaming dogs are another. I don't want to assign blame to anyone's pet [music] here. I just want to be honest that small mammals in a yard with regular cat traffic are facing a kind of pressure their ancestors didn't shape behavior around. Disease is another factor, and squirrels do carry a range of parasites and infections that hit younger, weaker individuals harder than established adults. Weather, especially unseasonable cold snaps or extended wet stretches, can take [music] a toll on juveniles whose fat reserves and shelter quality aren't yet up to adult standard.

[00:06:57]And there's the issue of dispersal, which is the term for the period when a young squirrel leaves the area it was born in and tries to establish its own home range somewhere else. Dispersal is necessary because no patch of woods or suburb can support unlimited squirrels on a single piece of ground, but it's also dangerous. The young squirrel is moving through territory it doesn't know, often crossing through other squirrels' established ranges, sometimes in a landscape fragmented by roads, fences, and buildings.

[00:07:29]>> [music] >> The trip itself is a risk, and not every juvenile completes it. I want to be careful here about urban versus rural differences because the honest answer is that the specifics depend on where you are. In some urban and suburban places, >> [music] >> certain pressures, like vehicle traffic or domestic pets, are amplified, while predator pressure from hawks and owls may shift in ways that aren't always obvious. In rural and forested settings, the predator profile tends to be heavier, and food competition with other wildlife looks different. What stays true across both is that a juvenile squirrel is facing a stack of pressures that an adult [music] has already, in a sense, passed through. The survivors you see are the ones who made it, which brings me to the part of this story I find most interesting [music] and most useful to know. Squirrels reproduce often.

[00:08:25]Many species in the United States have two breeding seasons in a year, and a mother can raise multiple young in each.

[00:08:33]From a casual human viewpoint, that looks like a sign of a species doing extremely well, almost too well. [music] But within wildlife biology, that pattern reads differently. High reproductive output is, in most cases, a counterweight to high early mortality.

[00:08:51]Animals that lose a large fraction of their young before maturity tend, over evolutionary time, to produce more young to begin with. The abundance you see, >> [music] >> in other words, is partly the visible side of a survival math you're not seeing the other side of. That's not a sad fact, [music] it's just a more accurate one. And once you carry it with you, the squirrel on the fence post stops looking like a generic backyard animal and starts looking like the outcome of a specific narrow corridor it managed to pass through. The adults you see have, in a real sense, already done the hard part. I think this changes how you watch them, at least it has for me.

[00:09:32]When I see a squirrel that is clearly small with a slightly thinner tail, a faster and less certain gait, the kind of squirrel that pauses too long in open ground, or takes a route an experienced squirrel wouldn't take, I no longer read it as a cute young animal. I read it as an animal that is currently in the middle of the most dangerous year it will ever live through. Most of them won't make it. Some will. And the ones that do will become the unhurried, route-following, fence-pausing adults that we so often mistake for proof that life is easy for squirrels. [music] There's a quiet line I've learned to respect with wildlife, by the way, which is that the moment an animal looks injured, or weak, >> [music] >> or unusually willing to approach a person, the most caring thing is almost always to step [music] back and call a licensed wildlife rehabilitator, or your local wildlife authority. Young squirrels in particular sometimes appear lost when they are not, and [music] intervening can do more harm than waiting and watching. So, the next time you see a juvenile squirrel, the small one moving a little too quickly, or a little too uncertainly along your fence, I just ask you to hold one thought in mind. You are looking at an animal in the middle of the hardest year of its life, working [music] its way through a landscape that did not arrange itself for its survival, on instinct [music] that is still being written. Whether that particular squirrel makes it or not is not yours to decide, and probably not yours to know. But the fact that there are any adult squirrels at all, anywhere in your neighborhood, is the visible end of a much longer and quieter story than abundance alone suggests. And once you've seen it that way, I think it's hard to walk past one again without slowing down, even just for a moment, to give that small creature its due.