[00:00:00] Michael Hawk: Hey, Michael here. Today's episode is a special one. Recently, our friends at Future Ecologies podcast reached out with an idea that went something like this. Hey, we all love oak trees, right? And masting those odd years when oaks produce tons of acorns. That's pretty cool and mysterious. Why don't we get a bunch of nature podcasts together and all release episodes at the same time about, or inspired by masting.

I thought it was a great idea. It's a mast of podcasts. In fact, we just released a brand new Jumpstart Nature podcast inspired by Oaks and Masting as well, and our friends at Future Ecologies, Golden State Naturalist, Outside In, and Learning from Nature: the Biomimicry Podcast are all releasing episodes in their unique styles as well.

Today's Nature's Archive episode is a re-release of my popular interview with Dr. Walter Koenig, covering one of the largest beneficiaries of masting the Acorn Woodpecker. And Dr. Koenig is also a masting researcher, so no need to [00:01:00] recreate the wheel when we already have this spectacular interview to share.

So please enjoy this critical mast event.

[00:01:12] Michael Hawk: As a nature lover I'm often asked what my favorite plants, animals and insects are. And I always struggled to answer those questions because I have so many favorites and they're kind of context dependent too. Sometimes it's just what I saw last. But when it comes to birds, woodpeckers often come to mind first. 

They're usually quite colorful, charismatic, and have such an amazing set of adaptations that let them drill into trees, excavate insects from bark and even fly catch on the wing. 

And one of the most interesting woodpecker species is the acorn woodpecker found in much of the west and south Western United States. They live in large groups. They're loud. If they have a clown face and can store thousands of acorns in specially drilled holes that are just acorn sized. Today's guest is Dr. 

Walter [00:02:00] Koenig 

he spent several decades studying these birds and affiliation with the Cornell lab of ornithology and UC Berkeley. Today, we'll learn about their behaviors, 

why you don't find acorn woodpeckers in the east, despite a nice variety of Oak trees and get this acorns aren't even their preferred food. Dr. Koenig has studied their breeding behaviors and group compositions, which is perhaps the most fascinating part of the interview. And I just can't do it justice in this short intro. So you'll just have to listen to find out. And if one studies acorn woodpeckers, it follows that one studies acorns too. 

So we also discussed the phenomenon of masting. That is when Oak trees produce bumper crops of acorns in synchrony across wide geographic ranges. In fact, this past year was a mast year for some Oak species in California. So, if you're interested in what causes masting, you might want to jump to the last 23 minutes or so of this interview. So without further delay, Dr. 

Walt Koenig. 

Okay, Walt, [00:03:00] thank you so much for joining me today.

[00:03:01] Dr. Walt Koenig: It's my pleasure.

[00:03:02] Michael Hawk: People often ask me what my favorite animal is or what my favorite bird is. And I always really struggle with those questions. These are just so many that you can really get interested in, but. By and large, I think when it comes to birds, I always say woodpeckers in general.

And today we're going to dive into perhaps the most interesting woodpecker. I might say the acorn woodpecker. so I'm really looking forward to it.

[00:03:25] Dr. Walt Koenig: I'd have to agree with that. Acorn woodpeckers are certainly very special, and woodpeckers in general are unusual and striking birds.

[00:03:35] Michael Hawk: Very charismatic, very noticeable. I'd be interested in how you got interested in acorn woodpeckers. So how did you, I guess, first get interested in nature?

[00:03:45] Dr. Walt Koenig: Unlike a lot of my peers, I was not really pushed into looking at birds or being interested in natural history when I was a kid. I always had a very unfocused interest, In [00:04:00] nature, I grew up in the suburbs of Chicago, where there was a little bit of nature left back in those days.

My primary interest got sparked when we go on vacation , and we always took road trips out to the national parks in the West, Places like Yosemite and the West Coast places where there was a lot of interesting nature.

I really had very little idea what any of it was, but it made a lot of sense to me that it was something that was pretty exciting. Eventually, I got lucky enough that when I was in college. By which time, as I say, a lot of my peers probably had, bird lists that were longer than the one I have now, but, I got shamed into, being interested in birds.

 I spent a summer working at the Field Museum in Chicago, which was a great place to get interested in natural history. And at the time, one of the things that, really sparked my interest was when [00:05:00] we picked up a bird that had been injured during the weekend and I brought it into a lady, up there who knew how to deal with sick birds.

And she, did so. I remember going back a week later and asking her what the bird was, whatever happened to it. I have no idea whatever happened to the bird, but I do remember asking her what kind of bird it was, and suggesting that it was a crow, because it was this black bird, and that was the only black bird that I knew of, and she looked at me like, I was from outer space, and said, no, it was a grackle.

And that shamed me into going down and getting a bird book and actually starting to get interested in looking at birds.

[00:05:40] Michael Hawk: Yeah. That's fun to think about those stories. When I think back on my own, you know, personal journey that I've been on, those little moments of discovering that there are like other birds or other species, other ladybugs, other whatever out there that, you know, to an untrained eye, maybe seem the same, 

Like this whole new world gets opened up. 

[00:05:58] Dr. Walt Koenig: Yeah, For sure. In fact, before [00:06:00] then, I remember going to some park where there were ducks, and somebody, and I have no recollection who, pointed out to me that some of them were wild ducks. They weren't just ducks that got fed with pieces of bread that people threw out to them, they were wild ducks that, flew up to the Arctic during the summer to breed, and I just thought that was amazing.

But that still didn't really get me going. It was really being shamed about this black bird that I had no idea what it was that finally made me think, huh, I better actually find out something about birds.

[00:06:34] Michael Hawk: so my understanding, I'm going to jump ahead a little bit, is that, for a, significant period of time, you led a study into acorn woodpeckers about behaviors of acorn woodpeckers at the Hastings Reserve. Now, so help, Connect those dots, then you, so you go from being shamed into having to learn a little bit about birds to now, becoming, you know, say the foremost expert in acorn woodpeckers.

what led to that?

[00:06:59] Dr. Walt Koenig: well, [00:07:00] there were similar, mess ups on my part, I would have to say. but I did end up going to grad school in natural history, I guess, in behavioral ecology is what I thought I might be interested in and I really was searching around for a thesis project and really was not doing terribly well focusing in on anything, until the guy, Michael McRoberts, who had actually started, An acorn woodpecker project picked down here at Hastings Reserve.

This was in the early 1970s. Gave a talk up where I was a grad student in Berkeley, and being rather desperate for a thesis at the time, I thought, well, maybe I'll go down to Hastings and see whether that might work out, because he was going to finish up and leave. So I did. Hastings turned out to be a nice place, and Michael McRoberts helped me kind of get going, and from there, I just got lucky in terms of acorn woodpeckers being a fabulous [00:08:00] bird to chase after.

[00:08:01] Michael Hawk: Absolutely. So let's, let's talk a little bit about acorn woodpeckers for those who have not seen one. can you give a description? What do they look like? Sizes? Colors? Where do you find them? Things like that.

[00:08:13] Dr. Walt Koenig: So, acorn woodpeckers are typically described as being clown faced. They do have a clownish type of visage, if you will. they are quite common along the west coast and in the southwestern U. S., but their range actually extends much further than that. They're in, the Big Bend of Texas. they have expanded in recent years.

They're now up in Oregon and have actually made it across the Columbia River into southern Washington. but more dramatically, they're quite common in the mountains of Mexico, both the Sierra Madre Oriental, and Occidental, going all the way down into Central America. And there are a couple of populations that actually live in Columbia.

Over that whole range, [00:09:00] they are dependent on oaks. So they really are dependent on the acorn crop. Which we'll get into at some point, but they're found pretty much only where there are oak woodlands and oak forests. They don't, for some reason, and have never been in eastern U. S. Where there are other woodpeckers that are related to them, but they are quite vocal They make a lot of fun noises that make them very conspicuous, 

[00:09:50] Dr. Walt Koenig: and they are relatively, I won't say tame, because in places where people aren't very common, they can actually be fairly scarce [00:10:00] and hard to see.

But in places and parks and things where there are a lot of people, they can end up being quite noticeable and easy to see.

[00:10:09] Michael Hawk: Yeah, that's right. and you know, with the name acorn in the name, it's easy to see there must be a connection with oak trees, though I know sometimes common names do lead us astray. So do they tend to live in, say, micro habitats where there's a diversity of oak species, or can they make do if there's, say, just, you know, if it's just homogenous, one type of oak?

[00:10:30] Dr. Walt Koenig: One of the really interesting things about the geographic distribution of acorn woodpeckers, is that they are not, strictly speaking, restricted to places where there are oaks. They tend to only be found in places where there are at least two species of oaks, which is for your listeners who are in California, why there are no acorn woodpeckers in Oakland and no acorn woodpeckers on the Berkeley campus because there is only one [00:11:00] species of native oak there, the Coast Live Oak. There are a few exceptions, one of which is down here where I live on the Monterey Peninsula, but for the most part acorn woodpeckers are restricted to areas where there is relative diversity of oak species.

The reason for that oaks, as we will probably get into later on, are masting species. They produce a lot of acorns, a lot of seeds some years and very few seeds other years. And if you're living in a place where there's only one oak species, you're going to have what amounts to an acorn crop failure fairly regularly, once every three or four years, which is basically once a generation, if you're an acorn woodpecker. And acorn woodpeckers just apparently are not able to make it in most such places. Whereas if there are two or more species, the species do not necessarily produce acorn crops synchronously.

And so, when you have several species of oaks, the probability of all of them failing during the same year [00:12:00] is very low, you only get a year when there are very few acorns, and the acorn woodpeckers end up being in trouble very rarely.

[00:12:07] Michael Hawk: So I think that there'll be a surprise a little bit later when we talk about, food preferences for acorn woodpeckers. But before we get there, like, how about nesting preferences? I assume like most woodpeckers, they're cavity nesters.

[00:12:21] Dr. Walt Koenig: Acorn woodpeckers are cavity nesters, and they also roost together in cavities throughout the year.

They are communal roosters. They live in family groups, and In some cases, the entire group will roost together in the same nest cavity, though sometimes they'll split among more than one roost cavities on their territory. During the breeding season, it's the breeder males that usually spend the night in the nest.

That is a woodpecker thing for some reason. Nobody really understands it terribly well. But beyond that, once the young fledge, everybody will [00:13:00] often roost in the same nest cavity. So nest cavities turn out to be very important and roost cavities are very important for acorn woodpeckers.

[00:13:08] Michael Hawk: When it comes to cavity creation, are they excavating their own cavities, reusing existing ones, using natural cavities?

[00:13:15] Dr. Walt Koenig: There's a lot of variation among different species of woodpeckers, which is one of the many interesting things about them. Acorn woodpeckers do excavate their own, roosting and nesting cavities, but they aren't all that good at it. They often take a long time to do that. They reuse old cavities about 50 percent of the time, so half of their nests are in a cavity that they have previously reused, not necessarily the year before, but in prior years, and that combined with the fact that they do roosts, In these cavities means that any territory really needs in any group of acorn woodpeckers does need to have several cavities that they can roost and nest in.

[00:13:57] Michael Hawk: Gotcha. And to me, one of the really cool things [00:14:00] about Acorn Woodpeckers is the behavior aspect. 

And that's, you know, one of the things I said at the beginning that woodpeckers are at the top of my list when it comes to like, what I consider to be my favorite birds, most interesting birds. And a lot of it is because their lifestyle is so unique, and there's a lot of adaptations that are required in order to be able to excavate holes in trees as we're talking about here.

so I'm wondering if you can just maybe give a synopsis of some of the interesting adaptations maybe that woodpeckers in general have or specific to acorn woodpeckers.

[00:14:36] Dr. Walt Koenig: Woodpeckers do have a whole series of interesting. adaptations. They, of course, have special feet, these zygodactyl feet, where they have two toes forward and one or two toes backwards. Helps them to actually grip onto trees that they're moving up and down upon all the time. 

[00:14:52] Michael Hawk: yeah, I mean, if you think of that, the classic woodpecker posture that you often see on a tree where they're just kind of like clung to the side, it's [00:15:00] because of those feet

[00:15:00] Dr. Walt Koenig: Exactly. they have these tongues, that go all the way around their heads so that they can stick them out, strikingly long distances. Back when I used to have a bird that I could show people, I would pull out his tongue and, it would go an amazing distance given that,

 as birds, they aren't that big.but they use that. They have a little barbs at the end. Uh, most woodpeckers, which are wood boring and are pecking into wood, looking at wood, trying to find wood boring insects will use that to pull out those insects. Acorn woodpeckers are largely fly catchers, so they're spending a lot of time fly catching up in the air.

They also leaf glean and bark glean in particular. One of the old names for them was ant woodpecker, and in fact they eat a lot of ants, which are often on the trees, living up in the trees around here. Woodpeckers are best known for their [00:16:00] pecking, their excavating behavior. They are able to excavate holes quite quickly when they put their heads to it. How they do that, I'm not a functional morphologist, but the functional morphologists who have looked into it, it's often said that Woodpeckers have these, you know, have to withstand these incredible, forces as they're pecking at the bark or the wood of a tree.

In fact, it turns out that if you work out the, forces given the, size of the woodpecker heads and the distance that they're moving it, basically what's known as the allometry of the situation of all the forces that are acting, that the the forces that they are withstanding are pretty much comparable to the forces that humans are able to withstand without, you know, serious damage to our brains.

 it's pretty striking what they're able to do, but a lot of it is because their [00:17:00] bills are quite strong. They do have some, uh, morphological adaptations in their skull structure so on that help them to withstand these forces, but mostly it's just that they, they are really good at pecking away at the, at the wood in the bark of trees. 

[00:17:18] Michael Hawk: Right? I attended a woodpecker seminar a while ago where, a fellow, presented and, He was talking about some of the musculature and how just the speed at which they're able to drum or tap, like comparing that to a human, try to tap at the same rate with your finger. And you can't, just so many levels of the, physical adaptations that, that woodpeckers have. 

[00:17:45] Dr. Walt Koenig: And that may be true though. I think if we were the size of a woodpecker, tapping your toe might be a lot different than it is when you're, , the size that we are, and that's turns out to be a lot of the sort of [00:18:00] key to what woodpeckers are doing compared to, you know, when we look at it, it just looks striking, And amazing. And it is, woodpeckers are striking and amazing, but a lot of the sort of physics of the situation works out pretty well when you're the size of a woodpecker. 

[00:18:17] Michael Hawk: there's so many different directions to go, but I am excited to talk about some of the, communal 

behavior. 

So just to recap, you were saying that largely they live in family groups. Can you break that down a little bit more in terms of male, female, juvenile ratios, uh, things such as that? 

[00:18:35] Dr. Walt Koenig: Acorn woodpeckers are what we call cooperative breeders. Cooperative breeding is, not terribly unusual, but pretty interesting social behavior found in maybe 10 percent of bird species, but it's quite uncommon in North America. There are quite a few elsewhere in the world, particularly in Australia, and also Africa has many [00:19:00] species of cooperative breeders It's a social system that's characterized by the fact that more than a pair of individuals is attending a brood or a nest at the same time. So there are also some mammals that are cooperative breeders. Uh, the famous one, of course, are meerkats, which apparently have their own, practically their own TV channel for them, I believe. Though I don't get TV, so I can't actually confirm that. But in terms of birds, there are several species in North America, the ones that people that may be familiar to at least a few of your listeners, Florida scrub jays, not the scrub jays in western, uh, US, . They are not cooperative breeders, but there's a distant population in Florida now it's, considered its own species, uh, which are cooperative breeders. There's another species in the southeast, the red cockaded woodpeckers, , and one which is probably familiar [00:20:00] to almost all of your listeners, at least in North America, which are crows. Common crow and elsewhere in the world, some of the other species of crows are also cooperative breeders. So cooperative breeding, again, you're talking about more than a pair of individuals attending we'll call it a nest because I'll be talking mostly about birds. Acorn woodpeckers are much more complex than your standard, what I like to think of as your simple cooperative breeder. Your simple cooperative breeders, such as those Florida scrub jays and also red cockaded woodpeckers, have what are known as helpers at the nest. So, young that fledged from a group. typically hang around in their natal group for a year or even longer during which time they'll help to raise Subsequent young and subsequent nests, which amount to be younger siblings in most cases, and that is also true of acorn woodpeckers. the young [00:21:00] that are produced in a nest will typically stay around for a year, two years, even longer, long after they have become adults and fully capable of breeding on on their own. They will still be in their natal group helping to raise younger siblings. But on top of that, acorn woodpeckers also have a very complicated mating system. There's what we call a Breeding core of individuals in any particular group, and a group can have up to six or seven breeder males, co breeder males, we call them, who are all competing for matings. With one, sometimes two, and rarely three, joint nesting females. And we call them joint nesting females because they all lay their eggs in the same nest cavity. So, acorn woodpeckers are, what is often called true communal nesters, in that more than one female lays eggs in the same nest cavity. 

[00:21:57] Michael Hawk: I know there's more to the story, but I wanted to [00:22:00] jump in. You're probably getting there. But when when you talk about, these multiple males and then multiple females in this, communal group, what are the relations to each other? Are the males related to each other or separate from other groups? You know, have they been kicked out or, or had to disperse from from another group and and join in or what, paint that picture a bit. 

[00:22:19] Dr. Walt Koenig: The simple story is that, yes, the co breeder males are all related to each other, they are typically brothers. or fathers and sons, or some combination of that. The females, the breeder females, similarly, if there's more than one, and most groups do not have more than one breeder female, but here in our study area about 20 or 25 percent of groups do, and when they have more than one, Those females are sisters or sometimes a mother and her daughter. So, since there's no outside mating, now your listeners will probably be aware that one of the big discoveries of the modern molecular [00:23:00] era has been That in a lot of these species of birds and mammals, uh, that are out there, that are what we like to call socially monogamous, they go around as pairs during the breeding season.

In fact, it turns out that the males are out looking for females other than their mate to try to mate with. Females are often mating with males other than the male with whom they are ostensibly mated. as a result, a lot of the offspring in some of these species are not sired by the caregiving male, by the male that the female is actually mated to socially. That Does not occur in acorn woodpeckers. Acorn woodpeckers have a really bizarre mating system, but they do not go out and mate outside the group. So the young in the group that are produced by this breeding core of individuals are all related to the breeders. And so [00:24:00] everybody in the group is closely related to everybody else. With one major exception, and that gets into sort of the next level of acorn woodpecker dome, which is how do these groups manage to sort of persist through time. And that was a big question when I started this study. Uh, that was in the early days. of the study of cooperative breeding People had really just sort of figured that these species typically consisted of birds that were related to each other and when you had helpers. So, for example, acorn woodpeckers have helper males and helper females. Birds of both young, both sexes, will often remain in the group after they fledged, And so, it just kind of made sense to a lot of people that if there was a vacancy, if the breeder females died, that her place would be taken over by one of the helper females After all, why else should she be staying there other than the [00:25:00] possibility that she would be able to inherit the breeding status of her mother who's in that territory? This pretty much assumed that what was determining reproductive roles In acorn woodpecker groups was reproductive competition. Reproductive competition is well known, particularly among mammal, mammalian societies. the reason why young mammals in a lot of societies aren't breeding is because the older males, fathers, would basically beat the crap out of them if they tried to mate with their mate. So that's the reproductive competition aspect of it. And reproductive competition does turn out to be very important in acorn woodpeckers, but it does not appear to be the major factor, at least at its only one of the factors that's determining reproductive roles among these groups. And the other factor is incest avoidance. So, birds that are [00:26:00] living in groups that have breeders of the opposite don't attempt to breed with those birds. Those are the non breeding helpers, as we call them in the group. If the female in a group dies and there is a reproductive vacancy, that vacancy is not filled by a helper female that might be in the group. Instead, it's filled by an unrelated bird from elsewhere in the population, and at that point, the breeder female is now unrelated to all the males in the group, including the helper males. who have fledged in that group, and they then can now become co breeders along with these older males, their father and uncle, who are still in the group and attempt to mate with her. Whereas the helper females typically then just disappear or are kicked out of the group.

[00:26:55] Michael Hawk: Oh, my head's spinning a little bit here. So I want to see if I'm 

[00:26:58] Dr. Walt Koenig: Yeah, that was a lot, I [00:27:00] realize, but they're complicated birds. 

[00:27:03] Michael Hawk: I, I I can I can see that 

now.

 So if we could like magically start at like time T equals zero and there's like this, group already in existence. So at the, at the very beginning, the females are unrelated to the males. Is, am I correct? 

[00:27:19] Dr. Walt Koenig: So, let's, if you, if you get a new group, and new groups do form occasionally, it's going to be maybe two brothers who will join up with a female, an unrelated female from some other other group. And it's, Unusual for them to be able to find decent territory where they're going to be able to be successful. And that's a large part of why we believe they live in groups to begin with. But it does happen. One of these occasions where you get one or maybe two, three brothers who start a group with an unrelated female. They then have a nest,fledged [00:28:00] young, all, both both or all three of those males are going to be competing for matings with the breeder female,uh, so they don't pair up in any traditional manner. Uh, the young that are produced from that nest, Both males and females, and you know, they don't have particularly large broods, but they could easily fledge three or four young. they are going to be, stay around in their natal group for a year or two at least, uh, during which time they're going to be helping their parents. Of the males, one of them's their father, they don't know which one it is. The others are basically uncles, okay, but they're all closely related to them. They don't know who's who, but they do know they're close relatives to all three of them. And they know they're closely related to the female. Uh, so they're just going to help to raise younger siblings. And the critical juncture. Comes when the breeders of one sex or the other die. So if there are two breeder females in the group, joint females, [00:29:00] and one dies, nothing in particular is gonna happen. The group's gonna continue with that one breeder female. But if there's one breeder female, or if both those females die, then there's a reproductive vacancy. Now there are complications. That I'm not going to get into because then it just gets too messy. But the simple story is that that vacancy is not going to be filled by one of the helper females. If there happens to be one the group, it's going to be filled by. a coalition of sisters that are then going to come to that territory and fight it out with other coalitions of sisters, to fill that vacancy and become the new breeders in that territory. 

[00:29:44] Michael Hawk: Okay, so I have a question about that. how, do these various coalitions of sisters discover that there's an opening? Are they just kind of always poking around at neighboring, colonies to, to, to see what the response is? 

[00:29:57] Dr. Walt Koenig: As far as we can tell, [00:30:00] yes. They spend a lot of time foraying, basically moving around to different territories, checking out who's there, who's around, what's going on. They know who many of these birds are. we have some quantitative evidence for that, from the work of one of my grad students, Mickey Pardue, who did a great job looking at cognition of acorn woodpeckers and demonstrating that they could recognize birds that are talking to each other, saying hello to each other, that are from different groups or groups that where they shouldn't know who each other is, they can actually, they know who a lot of the birds in the surrounding territories are. Even though it's still kind of a mystery, we do know that they can discover, at least at certain times of of the year, they can discover a vacancy literally within minutes of it happening. And we know that because we will [00:31:00] capture birds, At dawn, try in their nest, in their roost holes when we need to band them, uh, when there's an unbanded bird in a group and we are trying to catch them.

And if in that process we happen to capture, say, the breeder female, the only breeder female in a group, we need to get her back out there as quickly as possible. Because by the time the sun is beginning to come up and the birds are beginning to move around, If we aren't careful, there are already birds who have found that vacancy and coming into that territory trying to start something up to fill that vacancy.

And this starts what we call these power struggles, which are these fights to fill these vacancies. And power struggles are really exciting. it's something which if any of your listeners, who are within the range geographic range of acorn woodpeckers, they ever go out and hear a [00:32:00] lot of activity of acorn woodpeckers. It could be a power struggle, and they're just, they can just be incredibly exciting to watch. 

[00:32:08] Michael Hawk: Yeah, that's something I'll have to keep an ear out for. Often when I hear woodpeckers getting really vocal, I wonder if there's an owl or, you know, a predator or something. And actually I want to get into vocalizations here in a moment. but I'm wondering this in the banding program, having to get the female, the breeding female back so quickly, uh, I'm assuming that that was a, discovery by accident of how quickly then the the neighboring coalitions move in. 

[00:32:32] Dr. Walt Koenig: It is kind of learning the hard way. I mean, we used to do a lot of these ambushes, is what we called them. It's really one of the major ways we would try to keep the population banded, because in order To do the kind of work we're interested in, where we're really interested in the behavior of individual birds, we really have to know who every individual is within the group.

And that means keeping them banded with color bands that we can then [00:33:00] read from a distance away. to tell who they are, , when we banded them, where they came from, whether they are fledged from that group, or whether they're immigrants that came into the group. And that's sort of how we can begin to decipher the complicated social system of a bird like the acorn woodpecker.but yes, uh, we used to do a lot of these ambushes, at pre dawn in the morning because we figured, well, okay, we get them in the morning. Uh, we can try to band them and bleed them before it gets light. And that way, when it does get light, we'll let them go. And hopefully they'll just think it was all a bad dream. but. Especially early on, we would do that and, uh, you know, kind of wait till it began to get light. And then that's when we would start having problems if we caught one of these birds that, basically meant that because we had the bird in the hand, there was a vacancy in that territory. And, [00:34:00] It was just amazing, literally within 10 15 minutes, there could be birds out there starting to squawk and act like they wanted to, uh, start causing trouble and start a power struggle to fill that vacancy. 

[00:34:14] Michael Hawk: Yeah. And you don't want to reintroduce that breeding female into the middle of a power struggle. That's not exactly low impact to that female. 

[00:34:22] Dr. Walt Koenig: Exactly, because if you're not careful then, and that power struggle really gets going, that female may or may not be able to get back control of her territory. In which case, he's just kind of messed up the entire. you know, social behavior of that group for an indeterminate amount of time. 

[00:34:39] Michael Hawk: I know there's so many other directions we can go here, but, but one other kind of lingering top of head question for me is if you have a successful breeding group and they've, been producing multiple offspring year. after year. I'm assuming at some point the group grows too large or maybe there are too many helpers. Um, you know, what, what happens [00:35:00] in those scenarios? 

[00:35:02] Dr. Walt Koenig: one thing I didn't stress is that group size varies considerably within the population, so there are a lot of, what you could call a simple pair, one male, one female groups. There's some groups that have one male, one breeder male, one breeder female, and one helper who's from the prior year.

So trios, uh, you can, you can have all combinations. You can have groups that have one breeder male. two breeder, two joint nesting females, and they may or may not have helpers. there are more groups that have,co breeder males, than joint nesting females, but you can also have both. Now, at some point, the largest breeding group we've ever, I think, had, it was into the low teens. Uh, so that's a group that has maybe three or five. co- breeder males, could have two joint nesting females. Plus, it's been a successful group that has a bunch of helpers that are still around [00:36:00] from prior years. they then can, may fledge a bunch of young. And a couple of years ago, for the first time in the fall, we actually had a group that had 21 birds in it.

 that was just strikingly unusual. And it does not last very long. It's just too many birds for the group to really be able to handle. We don't really know why because they do have these which I think I alluded to, but we will talk more about granaries where they store acorns, and that's an important, backup food resource for them. But 20 birds, it's a lot of birds, and unless there are a lot of acorns out there, uh, they end up having problems, and many of those birds will end up leaving, and one way or another. and trying to find a territory somewhere else that they can move to. Whether they're successful or not, that we don't know. There are birds out there who are [00:37:00] wandering around who are, just don't have a group affiliation. We don't think there are very many of them, because we don't think that's a particularly successful way to get a breeding position in the population. But there are a few out there. And we don't really know what limits group size, but we do know that having a group that has more than 10 or 12 birds is pretty unusual. 

[00:37:23] Michael Hawk: It's interesting to know what happens when you hit that, threshold. so it sounds like some, uh, more discoveries ahead. 

[00:37:30] Dr. Walt Koenig: Yeah, as I like to say, somebody really needs to study these birds someday. There's a lot that we still don't understand. 

[00:37:38] Michael Hawk: And, uh, you know, I alluded to the vocalizations and I think one of the things when you live or hike or just spend time near acorn woodpeckers, very often you hear them. before you see them. And a lot of people characterize one of their vocalizations kind of sounding like a laughter in a way. so I'm curious, like as woodpeckers go, they seem to be more vocal than many [00:38:00] other species. maybe that's true, maybe not. I'd be interested in your perspective and, if you could tell me a little bit about their vocalizations and what they mean and how they relate to their communal, behaviors. 

[00:38:10] Dr. Walt Koenig: They are more vocal than your standard woodpecker that basically just, you know, you'll hear it. Drum or you'll, you know, they'll make those quick little notes that they make that tell you you have a Hairy Woodpecker out there, or a Downey Woodpecker or whatever.that's almost certainly because they are highly social.

Acorn woodpeckers are a member of a genus of woodpeckers, of which there's several other species in North America. Lewis Woodpeckers in the west, redheaded woodpeckers the East. They aren't all social, even though there are quite a few species in Central and South America that also are cooperative breeders Although nobody has ever really studied them, but they're often found in groups Many of the species in that genus are fruit eating of one sort or another. So, acorn woodpeckers [00:39:00] are pretty much at least in terms of fruit, focused on acorns. But, many of them have a diet that is far more diverse than your classic woodpecker, which is out there pecking around in the wood looking for these woodboring insects. Acorn woodpeckers eat a lot of insects. They are insectivores, like other, uh, woodpeckers, but they are not looking for them inside the, bark of the trees. They are fly catching, as I already mentioned, and bark gleaning and then supplementing that with this fruit eating habit. They also sap suck. are known to have the genes which allow them to both taste and digest sugars, which not all woodpeckers have, I believe, or certainly not all woodpeckers are known to have, but probably most of the woodpeckers in that genus have, who are frugivores. so they sap suck a lot, particularly in the [00:40:00] summer and late winter around here, when the sap is beginning to flow in the trees, they make sap holes, which are different from sap suckers. So you can kind of tell them apart. but they they do sap suck. In fact, I've had a group, three or four birds that were coming to my hummingbird feeder, chasing off the hummingbirds for the last couple of of months. 

[00:40:21] Michael Hawk: I want to go back to the fly catching because when I lead walks, or bio blitzes, and we have acorn woodpeckers in the territory, I, I always love to point out the fly catching behavior, because stereotypically, that's not what you expect of a woodpecker. And they seem very good at it, too.

Uh, they're they're surprisingly nimble in the air. Uh, how common is that among woodpeckers? 

[00:40:44] Dr. Walt Koenig: Again, it's something that I think is found pretty commonly in that genus. Uh, so I haven't spent a lot of time watching red headed woodpeckers in the east, but Lewis woodpeckers, which are pretty closely related and equally bizarre from acorn [00:41:00] woodpeckers, they fly catch a fair amount.

I mean, they're classically known for looking like small crows out there when they're fly catching. But acorn woodpeckers, that is really one of their main sources of food. They're dependent on acorns, but acorns are not a particularly good food resource.

And insects, of course, are much better. They're like 30, 35 percent protein. And so that's a much better food. source for them. And any particular day when it's not rainy and cold out there, they'll be out 

[00:41:34] Michael Hawk: And you did mention that, alternative common name, um, reference that they, they eat ants. And when I think of ant eating woodpeckers, a lot of times I think of the Northern Flicker who maybe will even find a colony on the ground and, and, you know, stand on the ground eating ants.

Do, do acorn woodpeckers ever forage on the ground in that way? 

[00:41:54] Dr. Walt Koenig: Yeah, they don't like going to the ground. There's scary stuff on the ground. Uh, [00:42:00] snakes. They don't want to be down there with the snakes. They do go to the ground, but It's not particularly common. I mean, you will see them occasionally go down and retrieve an acorn that they dropped. Presumably, they go down, perhaps most commonly, to get grit, because they, like most birds, sandy grit to help them digest things. so they're getting most of their ants up there in the trees, because that's, and there are a lot of ants up in the trees too.

Uh, it's one of the things that actually made climbing up to the nests of acorn woodpeckers the most challenging, was that sometimes those ants are just terrible and they'll just climb all over you as soon as you get up in the tree.So, uh, they could make climbing trees pretty unpleasant. but ant-eating woodpecker. It's, it's one of the old names for acorn woodpeckers. It, uh, nobody's used that for quite a while. 

[00:42:55] Michael Hawk: Yeah. That was new to me. Um, which is, which is why I was curious about that. a [00:43:00] little bit so let's finally get into the granaries. I know that's like a lot of times what people lead with when they talk acorn woodpeckers. so these granaries, I've seen some just immense ones.

Can you describe what a granary is, what it looks like, what's going on at this place? 

[00:43:14] Dr. Walt Koenig: Acorn woodpeckers are tied to acorns and oaks, as we've already talked about. And part of it is that they have developed a striking habit of drilling individual holes in, 

[00:43:28] Michael Hawk: And was that a pun by the way, a striking 

[00:43:31] Dr. Walt Koenig: I mean, well, yeah, okay, I'll accept it. A striking habit of drilling these These individual holes in the dead tissue of trees. Uh, and other structures. They, of course, are well known for doing this in buildings and, and people's houses Telephone

poles. so they'll drill these individual holes that they'll then harvest acorns in the fall as they're maturing and put them in these little [00:44:00] holes. Now, the point of that. as I said, is that it has to be in the dead tissue of a tree. So it's always in dead limbs or the bark. It has to be in a species of tree that has relatively thick bark where they aren't piercing into the living tissue of the tree, because they, the whole point is that they're doing this in the late fall, early winter, when around here in California, uh, that's when it starts getting wet and cold and rainy. And the whole point is to allow these acorns to dry out and to not rot and mold during the winter. So although they will occasionally stuff acorns in a cavity where they'll stick hundreds of acorns to fill up the cavity, that's not the first place they'll put the acorns and they'll only do that once they've kind of run out of other places to put them. Because if you do just take a whole bunch of acorns and stuff [00:45:00] them in a cavity in the winter, they're just going to rot. Whereas you put them in these holes, they're often facing down so that they stay dry, even though it's rainy and wet in the winter. As I've already mentioned, they aren't really good at drilling holes, cavities, but they, they do it. And so they'll drill a few dozen hundred of these a year, and they'll just keep doing it. They'll reuse these these holes over and over again during the winter and each year when the acorn crop matures. And so if they happen to have a nice. tree, that is going to be around for a while, they can end up with a, granary, as we call them, that has tens of thousands of holes. These big granaries, , which end up being kind of famous because they can be pretty striking,are not all that common because These birds are trying to drill these holes as fast as they can, just to make up [00:46:00] for holes that are being lost for one reason or another, because often the limbs are falling during the winter, the tree is falling apart, You know, they have to work pretty hard to maintain a granary that's going to have a thousand, a couple thousand holes, and allow them to last through the winter and the spring. But it does become an important food resource. I do have to mention that there is the great story about acorn woodpecker storing acorns, not for the acorns, but for the grubs, typically weevil larvae that live inside the acorns and eat the acorn meat. Uh, and if you actually pull out an acorn from a granary early in the winter, you will often find either the holes that the weevils have come out of, or if you open up the acorn, you may even find a couple weevils still in there. the fact is that this is known fondly as the grub theory, and it was conclusively disproved back around, [00:47:00] uh, you know, over a hundred years ago now. because if you actually watch an acorn, woodpecker, eat an acorn, you can see them pull the acorn out, bring it over to a tree where it has what we like to call it, an anvil where they can stick the acorn and start pecking into it. And then they will actually, you can actually see them eating bits of the acorn. So they are actually storing acorns for the acorn meat, not for any of the grubs that might live inside them. But they are an important food resource, allowing them to survive through the winter as permanent residents. Uh, here in California, they are permanent residents throughout most of the state, even in places like Yosemite Valley. where it's cold and snowy and wet in the winter, but there's still permanent residents because they can go and pull out an acorn if they have to during the winter. They can feed bits of these acorns to [00:48:00] their young in the spring when they have nests, when it happens to be cold and wet and crummy in the spring as well, which even here in California.

It can be for a few days in April and May. 

[00:48:13] Michael Hawk: The fact that managing the granary is, is a lot of work when we were talking about the size of these, uh, communal groups. how are the granaries managed, for example, are rotting acorns removed? 

[00:48:26] Dr. Walt Koenig: , they certainly check on the acorns. as they dry out, they shrink, and the birds spend a lot of time in in the winter just sort of checking on them, and if they don't fit very well anymore, they will pull them out and move them to a hole where they fit better, because then they do also spend a lot of time defending them against the titmice and the quail and the ground squirrels. And everything else that might come and want to steal those acorns when they are no longer available on the oaks themselves. Because by the time you get [00:49:00] to January, and February, and March, and later, in a typical year, those are the only acorns that are going to be around. And so there are a lot of animals out there that would like to get those acorns. And of course, having them, Carefully packed in those granaries makes them difficult for anybody else to get them, and the birds then defend them against all these other species. As well as other acorn woodpeckers that might want to come and try to steal them. 

[00:49:27] Michael Hawk: I remember observing one time, uh, granary and I want to say there were two acorn woodpeckers, that were both. A few feet away from each other and it looked like they were putting fresh acorns into holes and a pair of of corvids came flying and I think they were crows, though my memory may be failing me.

They may have been ravens. But nonetheless, it spooked the acorn woodpeckers and they hadn't quite gotten those acorns all the way wedged in there yet. So it was an easy meal for those corvids. and I was surprised that I didn't see like a defense from other acorn woodpeckers. They just kind of let [00:50:00] those, corvids Take those acorns. I'm curious a little bit about that defense that you spoke about. Part of it is getting that acorn in there in the first place where it's hard for somebody else to get it out. But how, how do they react to somebody coming in and taking their food? 

[00:50:13] Dr. Walt Koenig: They do try to defend their granaries, but a crow is, what, it's five, six times larger than an acorn woodpecker. And often they do come in packs. crows are also cooperative breeders, and so you can get two or more of them coming in at the same time. And, acorn woodpeckers as, uh, As aggressive as they might be, I think, when something like, uh, three or four or five crows come in, it gives them pause there isn't a whole lot they can do about it. In general, they're pretty good at defending their granaries. They'll certainly chase away ground squirrels, which will come after the acorns in the spring. Uh, what's really a lot of fun is this time of year, you'll get years when there are only a few trees that have a lot of acorns. [00:51:00] it's not a very good crop in general, but. There'll be one or, you know, there'll just be a couple of trees that for some reason have done very well. And so everybody just piles into those trees, trying to get those acorns as fast as they can. And you'll get both crows and you'll get all these scrub jays coming in, not just the scrub jays that are in that area, but you'll literally get dozens of scrub jays coming in one after another, taking an acorn and then flying off with it and then storing it somewhere. The poor woodpeckers that might happen to live in that territory. It's just kind of sad watching them trying their best to defend the territory, but ultimately they get overwhelmed and there just isn't much they can do about it, but they try. And you know, the woodpecker group may have six, seven, eight birds and they'll all try to defend it, and crows, certainly a raven. ravens have just started showing up here [00:52:00] at our study site, but the crows are pretty common, and they're big enough. to give an acorn woodpecker a lot of pause. 

[00:52:08] Michael Hawk: Well, that makes a lot of sense, especially in that context. So we've alluded to acorn production in good years and, maybe we even used the word masting earlier. I can't recall, but, uh, can you tell me what masting is? 

[00:52:21] Dr. Walt Koenig: So masting is the variable and synchronized production of seeds of plants, and so, I'll talk mostly about trees because that's where it's been most studied and what I've been most interested in. we realized early on that the demography of acorn woodpeckers was highly dependent on the acorn crop. So, in a really bad acorn year, which we had early on. A lot of the birds end up leaving. They disappear. A lot of the population just ends up disappearing from the study area. A few of those birds came [00:53:00] back the next spring, but a lot of them, of course, never did. In a really good acorn year, acorn woodpeckers not only breed, in the spring. And can have two nests here here in, uh, Central California. but they can even sometimes breed in the fall, right now. So, we actually have run across a few nests when we were out there counting acorns. The latest baby woodpecker I've ever banded here at Hastingswas, November 1st. So, in a really good acorn year, they can start a nest in sort of the latter part of August and during September. And they can be fledging young in the latter part of October or even early November. Their demography is really dependent on the acorn crop, and that got us interested in trying to quantify the acorn crop. There was a little bit of work on it, but people didn't seem to know a whole lot about what it was what was affecting the acorn crop. It becomes pretty complicated pretty quickly because [00:54:00] we do have multiple species of oaks here at Hastings. but we figured we'd do what we could. And, that was, quantifying the acorn crop to try to understand their masting behavior. So the interesting thing about masting is it's not strictly speaking something that an individual tree does. So a tree may produce a lot of acorns one year and not very many or no acorns another year. But masting is a population level phenomenon. It's something that all the trees in the population are doing more or less at the same time. So in a good mast year, all the individuals Of whatever species we're talking about, are going to produce a relatively good acorn, crop whereas in a bad mast year. none none of them, or very few of them, are going to produce any acorns at all. 

[00:54:50] Michael Hawk: Do you ever see a case where masting crosses, and I suppose this could just be coincidental, but do masting events ever cross [00:55:00] species boundaries or like maybe affect an entire section of oak trees? 

[00:55:03] Dr. Walt Koenig: They can cross species boundary but that then gets into what is sort of determining how does a population of trees decide when it's going to produce to put all its energy into acorn production? And. those factors can be similar among some species so that you can get some synchrony in acorn production among different species. But one of the things that really sparked my interest early on was this definition, which was synchronous production of seeds by a population of trees, but what no one seemed to really care too much about or have spent a lot of time studying was how big a population we were talking about. So was it just the trees right here at Hastings? These trees that we have here, including Valley Oaks and Blue Oaks, found all around the state, around the Central [00:56:00] Valley of California. So they cover millions of acres. And so if it's a good acorn year for Blue Oaks here in Hastings, is it a good year up in the Bay Area around Oakland and the Berkeley Hills?

Is it a good year in the foothills of the Sierras? Or what? Nobody seemed to really understand. And so it took us a long time before we kind of realized that, in fact, the population we were dealing with was much larger than people had suspected. And, in fact, for some of the species, at least, it pretty much encompasses their entire geographic range. Which, For example, for Oaks does encompass the foothills of California going all the way up to, the, Great Central Valley.Basically, you know, the north around Redding and so on, and then all the way down into Los Angeles County at the southern end of the Great Central Valley. And So then that [00:57:00] raises the question of what then is sort of driving this pattern where, what, causes these tens of millions, maybe hundreds of millions of trees to all kind of decide, okay, This year, we're going to put all this effort into producing acorns. 

[00:57:15] Michael Hawk: right. I mean, I suppose to, to a lay person, they're probably like, well, it's gotta be the weather. but I think it's more complicated than that. 

[00:57:22] Dr. Walt Koenig: Well, not necessarily. In fact the weather is probably the main driver of what's going on. The two things that correlate strongest with the acorn crop for most species, it varies from species to to species. so that's why, you know, it's hard to generalize across everybody.but the 2 things that are the most important for, say, the valley oaks, or the blue oaks, uh, which are species, which at least a lot of your listeners here in California will be familiar with, conditions during the spring, when they're flowering, so these are species that are [00:58:00] flowering in February and March and April, and then those flowers that are what, then mature into acorns the next, fall. And so the conditions during the spring are very important. And then the complicating factor and the one that sort of really makes things difficult is that it also depends on, what the acorn crop was the year before. 

[00:58:23] Michael Hawk: Hmm. 

[00:58:24] Dr. Walt Koenig: So if they put a lot of energy into and had a very good acorn crop last year, then they tend not to have a very good acorn crop this year. And this is what really tells us at some level that part of the story is that they're storing energy somewhere in the tree when they use up a lot of that energy to produce a big crop of acorns, it takes a while for them to restore that and be able to produce another good crop of energy. And the real complicating factor comes because trees are really complicated [00:59:00] structures and it's really hard to figure out where they're storing and what they're storing. We don't even know what the critical resources are that they're storing up to produce an acorn crop. And so it's been very difficult for the people who really are into that sort of, that aspect of things, to really figure out what's going on in terms of resource storage, and then how they decide when to actually put those resources into acorns. Now, the interesting thing that I will mention in terms of valley oaks and blue oaks, again, these two very common species that are ranged throughout much of California, is that when they tend to have a really good acorn crop is when conditions are warm and dry during the winter and spring, presumably, because that fosters pollination in the spring.

These are all wind pollinated species, that's why they produce these catkins that are producing all this [01:00:00] pollen in in the spring that's getting blown around, and it's that pollen, which has a very hard time pollinating and fertilizing the flowers when it's a cold, wet spring. when it's warm and dry, that's when they tend to do better in terms of having a good acorn crop in the fall. 

[01:00:19] Michael Hawk: My understanding is that you have, I mean, as you said, you try to quantify the acorn production. And, how long has that research been going on? 

[01:00:29] Dr. Walt Koenig: We started quantifying the acorn crop here at Hastings. back in 1980, when we really got interested interested in the spatial pattern, what's called spatial synchrony of acorn production. In other words, trying to figure out how big a population. was, producing acorns synchronously.

It turns out to be a whole kind of interesting story in and of itself, which I won't get too far into, because as one might expect, synchrony does decline as [01:01:00] you get farther away. So it declines with distance. So when you're talking about how the acorn crop here at Hastings and Central Coastal California is, well, it's almost certainly going to be more synchronized with populations with trees that are relatively nearby, but and when you get up to theBay Area which is, you know, now we're talking, eh, 100 miles away, 120 miles away, it's going to be less synchronous, but it is still statistically synchronized, at least to a lesser extent, with the trees that are here. And you can actually show that when you have enough data throughout the range of both Blue Oaks and Valley Oaks.

That even populations that are hundreds of kilometers apart, one end of the Central Valley to the other end of the Central Valley. do exhibit some degree of spatial synchrony, and that is presumably because, [01:02:00] as you mentioned earlier, the weather is one of the main driving factors and weather is rainfall and temperature is one thing which is well known to be highly spatially synchronized over large geographic areas.

[01:02:15] Michael Hawk: That makes sense for sure.and we very often in California have fairly consistent weather up and down the length of the state, but it does vary. There are some years where it's, you know, rainy in SoCal and dry and nor, you know, Northern California or vice versa. So I'm sure those provide interesting opportunities to look at the correlations with weather. 

[01:02:34] Dr. Walt Koenig: Right, yeah. 

[01:02:35] Michael Hawk: How does, uh, how's 2024 stacking up? 

[01:02:38] Dr. Walt Koenig: Well, I haven't actually, we just finished our statewide survey. It was all in all, is a good year, I would say. Blue Oaks are doing very well in quite a few places. We go to enough sites and there's enough variability that we do enough different species and it ends all, all ends up kind of, [01:03:00] becoming a big jumble in my mind, 

[01:03:02] Michael Hawk: until you put all the data 

together and 

[01:03:04] Dr. Walt Koenig: putting all the data together, but relatively speaking, it's it's a good year for blue oaks here, at least in the central coast. It's doing very well, and it was doing very well in several other sites that we do blue oaks. at. Valley oakshave not been very good in any particular spot, but they do have acorns. It's not a bad year. A couple of the other species we look at, Coast Live Oak is the the one that it does not, it is not found all the way around the Central Valley.

It's found from about, Just north of the Golden Gate, down along the coast into Baja, California. We don't go all the way into Baja, but we do look at several populations in Southern California, and I think they were doing pretty well there, too. They're certainly doing well here in Hastings. It hasn't been a good year for any of the species in recent years, and so I think even [01:04:00] though You know, it was a pretty wet winter. But despite that, I think it's been long enough since it's been a really year that some of these species have just decided they're going to go ahead and go for it, even even though, conditions weren't quite as favorable for it in the spring as it might have been otherwise. In terms of blue oaks, I did look at that. It's the best blue oak year here at Hastings since 1985, which is pretty good. I mean, that's a long time. Not that there haven't been a couple of good years since then, but, uh, in terms of the population in general, it's, it's a good year. There are a lot of acorns out there. 

[01:04:38] Michael Hawk: Given that it's seems to be at least for a couple of the, Key species here in California, good acorn year. What should naturalists be looking for when they're out and about? Are there going to be any interesting animal behaviors, acorn woodpecker behaviors, you know, things like that to pay attention to?

[01:04:56] Dr. Walt Koenig: Certainly when it's a good acorn year, and there are lots of [01:05:00] acorns, it is fun to watch. Well, acorn woodpeckers, harvesting those acorns and storing them, them, but acorns, despite the fact that they are not a particularly nutritious food resource, of course, they're incredibly bitter, which if any of your listeners, if they've ever tried to eat an acorn, are probably well versed in. Nonetheless, there are a lot of things out there which really try to go for those acorns, mammals and birds. And so it's fun watching them harvest the acorns, sort of interact with each other when they're in some of these trees that have a lot of acorns. you know, , it is possible to find nests of acorn woodpeckers in the fall, , in a really good year, which is really striking, uh, to see birds nesting in the fall. And I, and I think there are other species that might be doing that as well. there are a fair number of species here in California, certainly, that will nest occasionally in the fall. And I think several of those kind of [01:06:00] dependent on acorns. 

[01:06:01] Michael Hawk: Great. good to good to know. And One other kind of quick thought , that I had when you were talking about, you know, typically you don't have a good acorn production year back to back, the implication is there must be some energy resource or something like that that, uh, that mediates this. I was speaking with a tree phenology researcher phenology a few weeks ago, and they were telling me about the leaf economic spectrum, which for listeners, that's the concept where, uh, in general, you can measure the, the health of a tree by whether it is producing more energy than it uses to produce that leaf in the first place.

A tree needs excess resources to be able to grow. So it's kind of a simplistic. first pass at, what's going on with, this tree. And it got Me thinking, like, is there any way to quantify, I mean, these, some of these oak trees are immense and the number of acorns on the individual oak tree could be immense.

Is there any way to kind of first pass [01:07:00] guesstimate the amount of. Energy being produced by a tree versus the amount being consumed? 

[01:07:05] Dr. Walt Koenig: Well, I wish there were.. There have been several groups that have tried, and it is really difficult because trees are modular in many ways. You can measure the nitrogen, the phosphorus, and then whatever the carbon that's in a particular branch or in a particular, limb but you don't necessarily know what's going on in the rest of the tree. And then the big problem, the big black hole, has always been the roots. these trees are known to have really large root systems, but to actually get at what's going on in them has really befuddled the plant physiologists who. that I know of who have tried to get into that. So it's been a real challenge. As I may have mentioned, there have been several groups that have taken parts of the tree and looked at the nitrogen or the phosphorus or whatever, tried to understand whether [01:08:00] that varies depending on the seed crop or depending on what's going on in the tree.And sometimes they get, results would seem to make sense, and sometimes they seem to get results, which just show that it has nothing to do with seed production. It's been really difficult for those people, and I have to feel for them because it would be fun to really know what's going on. 

[01:08:25] Michael Hawk: Yeah. Yeah. the amount ofdiscoveries that we need, I think, to get to that point, it'd be a series of events to get there. It's been a lot of fun talking acorn woodpeckers and acorns and oak trees with you today.

Is there anything else that you think we've missed that you really wanted to tell our listeners about when it comes to these topics? 

[01:08:44] Dr. Walt Koenig: Well, that's a good question. Certainly being outside and actually paying attention to what's going on around you can be a life changing experience for anyone. When I was young, it took me a long time to really get to the stage [01:09:00] where I kind of realized how interesting the world was out there and how complicated it was. One of the things you learn by spending one's career trying to understand something like acorn woodpeckers is just how complicated and how interesting the world is around us and how much effort it takes to really get to the point where you begin to understand how things are working. I think that a lot of your listeners will have spent time paying attention to, listening, watching various nature documentaries and things. And one of the things a lot of us always talk about. when we get on to a discussion of that is just how much work goes into the little bits of snippets that end up in these documentaries that you'll see on tv and elsewhere and how much effort it takes to really be able to know [01:10:00] what's going on. when you just begin to appreciate, not just how much effort goes into it, but how interesting and complicated these animals are, it really is, can change one's life just in terms of being able to appreciate the outdoors and the world around us. So I think a lot of your listeners may already be at that stage. But any that aren't, it's, it's worth just spending time outside and whatever it is that happens to interest you, trying to think about what it is and, how it survives and how it manages out there. Because it's probably a lot more complicated than you might think. 

[01:10:40] Michael Hawk: Well, I love it. I am well aware of the benefits of nature and observing, but I have to remind myself still to to do it at times because I get too wrapped up in advocating for nature and not experiencing nature. So I appreciate hearing that. And it's a good reminder for myself. Are there any, projects upcoming, any work [01:11:00] from your graduate students that you'd like to highlight, 

[01:11:02] Dr. Walt Koenig: Well, I'm retired and no longer have grad students. But I do spend a fair amount of time here at Hastings, which is a place I came as a grad student and decided I never wanted to leave and was fortunate enough to pretty much be able to achieve that dream. It's a lovely part of the world. We live just a few miles away. The main bit of research I still do is trying to quantify the acorn crop, understanding acorn production. I am still interested in the woodpeckers and am trying to work on another book on them. I did write one back in my youth. Hopefully this one will be a little bit more fun. because I'm older and I think more fun than I was early in my career. And we know a lot more about them. They're pretty exciting birds and I'm hoping to sort of wrap up and bring together a lot of what we've learned [01:12:00] about them over the last 40 years, 50 years that we've been studying them. 

[01:12:04] Michael Hawk: Do you have a publisher or estimated date or anything like that? I guess I can keep my radar, attuned. 

[01:12:10] Dr. Walt Koenig: I have not bothered to, uh, To bug publishers yet, it probably will be an academic book, but still, I'm hoping to make it at least more accessible than back in the day. So, it'll, it's likely to be an academic publisher and certainly won't come out in the next year. But, I'm hoping to be able to wrap it up next year. Being a retiree, I'm trying not to work too hard at it, because then it just doesn't get to be quite as much fun. And they do turn out to be complicated birds. It's been a lot of fun, but a lot of work to kind of look at some of these analyses that I did 20 or 30 years ago and say, it's time to bring that up to modern standards and really try to bring it together with what we now know about acorn [01:13:00] woodpeckers. So I think it'll be of interest to at least some of your listeners, and it certainly will be fun to try to sort of put it together and get it published. 

[01:13:10] Michael Hawk: All right. Well, I think our circles overlap just enough. I'll probably see or hear about it when it happens, but, maybe to be a little more formal about it. Is there a place that people can go to keep track? , do you, are you on social media or do you have a website or anything like that that you'd like to share? 

[01:13:25] Dr. Walt Koenig: I do still have a website. It's through Cornell, and, if anybody is more interested, if they Google Walt Koenig Cornell, uh, University, it's sure to pop up. you just have to, ignore all the Walter Koenig Star Trek parts of, uh, the web. otherwise, I do try to keep it reasonably up to date and you can find out more about acorn woodpeckers and masting there. I did have a dual career, a couple of problems. So, after working here at Hastings for many, many years, we did go to Cornell and [01:14:00] I finished up my career at the Lab of Ornithology, Give a small plug for it because it was a great place and even though we're back here in California at Hastings, I do still have my website through Cornell University, hopefully for the foreseeable future.

[01:14:14] Michael Hawk: Well, I'll make it easy for people and include a link in the show notes so they don't have to sift through the Star Trek. Linksin Google. 

[01:14:23] Dr. Walt Koenig: It can be fun doing that. It's uh, yes, that would be 

[01:14:27] Michael Hawk: , I suppose if you just add the keywords, acorn woodpecker, it probably helps a little bit,

but 

[01:14:32] Dr. Walt Koenig: would be good.

[01:14:34] Michael Hawk: all right, well, thank you so much for spending so much time today. I appreciate the wealth of knowledge that you've been able to so clearly explain, and I appreciate you. So thanks again. 

[01:14:44] Dr. Walt Koenig: no problem. And uh, I look forward to hearing from you in the future.