Previous Birds of the Month can be found here.
It is dangerous to slam a portion of your body into a hard surface 15 times a second, with a force 1,000 times that of gravity. You or I could not do it. Yet acorn woodpeckers, like the 200 or so other species in the woodpecker family, are so extraordinarily designed that for them it is as relaxing a pastime as idling in a park. Here is one about to start hammering:
Male acorn woodpecker
A woodpecker’s beak is extremely strong, and built so it absorbs the impact of the hammering rather than transferring it to the bird’s organs or muscles. Its brain is small relative to the size of its body, and positioned so that it has maximum contact with (and therefore is maximally protected by) its unusually thick skull. Woodpeckers also have a thick third eyelid, which closes a fraction of a second before each stroke of the bill, in order to protect the eyes from the splinters that fly from the tree as the bird drills away.
Large white-billed woodpecker, demonstrating its strong beak
The woodpecker is so spectacularly fit for purpose that it is often used by creationists as proof of the existence of God. Ted Hughes displayed a poor grasp of woodpecker biology when he wrote
Pity the poor dead oak that cries
In terrors and in pains
But pity more
Woodpecker’s eyes
And bouncing rubber brains.
In some ways, the acorn woodpecker is a rather average example of the woodpecker family. It is average size and weight: about 8 inches and 3oz. Its plumage is on the minimalist end of the woodpecker scale: black and white with a striking red cap. (Other species throw brown and green into the mix.) You can distinguish male from female by looking at the cap: the male’s cap starts far closer to the beak, while the female has a black band between beak and cap. It lives in the woods and coastal areas of California and southern United States, through Central America and down to Colombia. Its eyes are spookily pale.
Female acorn woodpecker
Woodpeckers drill and drum for a number of reasons – to attract a mate, to establish territory – but mostly to locate insects that live inside the bark of trees. Once the woodpecker has drilled a hole in a tree, it pokes in its long, sticky, bristly tongue, wraps it round the ant or grub or mealworm and pulls it out to eat. In this moment of feeding, it is convenient for the woodpecker to have a long tongue. The rest of the time, however, it is not so convenient, and the bird retracts the tongue so it is wrapped around the skull and drawn into the nostril.
Woodpecker skull. That long thing curving around the outside is the tongue.
Acorn woodpeckers eat a fair number of ants, but their primary food source is acorns. It is this that makes the species exceptional among woodpeckers. Acorns are located on the outside rather than the inside of oak trees. Acorn woodpeckers therefore drill into trees not in order to find acorns, but in order to make holes in which they can store acorns for later use, and especially during the winter. Here is a tree which has been attacked by acorn woodpeckers:
You can see that some of the holes have been filled with acorns. Such trees are called ‘granaries’ and may contain more than 50,000 holes. The woodpecker’s main concern is to find a hole that fits the acorn exactly.
As the acorn dries out, it decreases in size, and the woodpecker moves it to a smaller hole. The birds spend an awful lot of time tending to their granaries in this way, transferring acorns from hole to hole as if engaged in some complicated game of solitaire.
Multiple acorn woodpeckers work together to maintain a single granary, which may be located in a man-made structure – a fence or a wooden building – as well as in a tree trunk. And whereas most woodpecker species are monogamous, acorn woodpeckers take a communal approach to family life. In the bird world, this is called cooperative breeding. Acorn woodpeckers live in groups of up to seven breeding males and three breeding females, plus as many as ten non-breeding helpers. Helpers are young birds who stick around to help their parents raise future broods; only about five per cent of bird species operate in this way.
Adult bird feeding younger one inside tree
Sometimes a single brood, laid by one female, will contain eggs that have different fathers. The similarly-aged half-siblings will be raised together by a combination of biological parents, adoptive parents, older half-siblings and adoptive siblings, until they are old enough to work in the family acorn business or go off and start a granary of their own. In short, acorn woodpeckers are some kind of super-species, evolved (pace creationists) to manage their physical and familial activity efficiently and harmoniously.
When animator Walter Lantz was on honeymoon in California in 1940, he heard an acorn woodpecker pecking and calling as it stashed acorns in the roof of his cabin. Lantz’s new wife suggested that he create a cartoon based on the bird; the result is Woody Woodpecker.
You may be thinking that Woody does not look much like an acorn woodpecker. If anything, he is closer to the pileated:
Woody also does not resemble the acorn woodpecker very much in sound. Inspiration works in mysterious ways. Here is the pleasant-ish call of an acorn woodpecker:
Here is the less pleasant laugh of Woody Woodpecker, repeated across a whole hour. I lasted 28 seconds. You?
Tags: animals, bird of the month, birds, hannah rosefield, woodpeckers
As the acorn dries out, it decreases in size, and the woodpecker moves it to a smaller hole. The birds spend an awful lot of time tending to their granaries in this way, transferring acorns from hole to hole as if engaged in some complicated game of solitaire.
This seems like an extraordinary level of effort when they could JUST EAT THE GODDAMN ACORN instead.
I find this extra funny because it contrasts with the whole thing where the creationists are using woodpeckers as an obvious example of intelligent design.
Intelligent my ass. You know where you can get bugs instead of hammering them out of trees? EVERYWHERE, LITERALLY EVERYWHERE, THERE ARE MORE BUGS ON THIS PLANET THAN ANYTHING ELSE.
Plus dried out acorns seem way less appetizing than fresh ones! Come on, birds.
Apparently caching acorns gives them a chance for the bitter tannins to leech out! I’d like more info from an expert on this, though, since googling “acorns” is returning a lot of investment websites.
Also, oaks only have acorns for part of the year, so the woodpeckers are ‘storing up for winter’, as it were. In my particular neck of the woods, there are no acorns on the ground by November–they have all been eaten, stored away by the various creatures that store acorns, or are buried under soil and leaves.
‘ transferring acorns from hole to hole as if engaged in some complicated game of solitaire.’ This phrase made me smile, and, really, doesn’t it describe most food storage, even that of humans?
Yesssssss. Winter is hard, and the goddamn squirrels keep burying the acorns and then dying. Gotta put them in a granary.
What you want is Walt Koenig’s research: http://www.nbb.cornell.edu/wkoenig/wicker/My_Rese…
He has been studying Acorn Woodpeckers for YEARS and knows more about them an anyone else.
This paper probably touches on your question but there’s no PDF on his website 🙁
The effects of tannins and lipids on the digestibility of acorns by acorn woodpeckers. Auk 108: 79-88.
Well isn’t that appallingly relevant. Nifty!
I briefly tried to get my co-op house in college to adopt the acorn woodpecker as our house mascot, since they’re so cooperative. If I recall correctly, my woodpecker lost to a flag made out of a sheet that said “flag” on it.
Oh I love woodpeckers! (we don’t have them in Australia, and also I like their plumage) This is great!
Eeeesh that picture of the wood with all the holes in it creeps me out. Oh hello trypophobia, nice to see you again!
(Hint: Don’t google that for the correct spelling because it will WRECK YOUR DAY.)
Yessss. The whole hole thing didn’t much bother me until the rash of articles about it. Somehow, thinking about it started to give me a little bit o’skin crawl. It still doesn’t rise beyond the level of heebie-jeebies, but I did have to scroll past that picture extra-fast.
I love these bird columns SO MUCH.
They are even more fun if you think about them as “Dinosaur of the Month”.
There is a red-bellied woodpecker at my parents’ house that likes to hammer into the gutters. I have been awoken many mornings by it ramming its bill into the aluminum and MAN what a racket that is.
I’m a big fan of the bird columns – thank you so much for sharing!
I’ve got one that likes to bang on the metal inside my chimney. It’s a very early riser. I’m not very fond of woodpeckers at the moment.
There is a red-bellied woodpecker at my parents' house that likes to hammer into the gutters. I have been awoken many mornings by it ramming its bill into the aluminum and MAN what a racket that is.
I'm a big fan of the bird columns – thank you so much for sharing!
I have seen those before! (the granaries). and NOW I KNOW.
When I lived in New England, I battled a woodpecker. I’d rush outside with the broom I kept at the back door and wave it at the little bastard. I aimed carefully to never hit him, though. I did admire his beauty. But he was not welcome to drill a hole or build a nest on my house!
I was skirting the law. This bird was an endangered species and it was illegal to harass him, with steep fines for destroying a nest. I wanted him to be happy and free … and off my property! Had to shoo him away before he established any nest!
I got twitchy after twice daily having to leap up and sprint to the back door. So I rigged the back deck to safely accommodate my little dogs. Much better routine ensued: hear woodpecker hammering my house, let dogs out onto the deck, where they barked their fool heads off and frightened away the bird. The little dogs are not birders, but did consider him anomalous and therefore a potential threat to their human (me) and their home.
Only had to send the little canines outside half a dozen times before the woodpecker decided the dozens of trees on my acre of property were better suited to him. Dozens. Available the whole time he’s been pecking at my house. And then there were the 100 acres of undisturbed forest beyond my property.
So yeah, bird brain. But very pretty.
There is something indefinably creepy about a creature spending its life taking the seeds of a tree, which were meant to be scattered far from all trees and into the ground, and putting them inside the slowly-dying-of-this-process husk of another tree instead. It’s like an alien has heard about reproduction and decided to help but got horribly confused.
*BANG BANG BANG BANG BANG BANG BANG BANG* *flutter*
*achingly silent pause*
Ahhhhh! *zzzz*
*BANG BANG BANG BANG BANG BANG BANG BANG BANG*
Goddamit.
(I kid. (Sort of.) I am very fond of acorn woodpeckers, except when I am trying to sleep.)
I can’t believe no one has commented on that tongue.
That tongue is THE MOST GROTESQUE AND AMAZING THING I HAVE EVER SEEN.
Same here. I had NO IDEA. And I still don’t quite understand how it works. The tongue wraps around the skull but does it go over or under the skin?