Bird Watcher's General Store

Acorn Woodpeckers Stash Acorns - 10/10/08


Dear Bird Folks,

I've just returned from a bus tour of California. At one particular stop the tour guide pointed out a "woodpecker tree." The tree was filled with hundreds of holes. Many of the holes were filled with acorns. I asked the guide what kind of woodpecker had created this riddled tree, but she didn't know. Do you know what kind of woodpecker made all of those holes and do we have those woodpeckers living near us?

- Gus, New Britain, CT

Good one, Gus,

Your question sounds like the title of a mystery novel. The Riddle of the Riddled Tree. Let's examine the evidence. You say there was a tree. A tree filled with holes. Yup, that sounds like the work of a woodpecker alright. So far everything is adding up. But then you added a twist. According your story, some of the holes in the tree contained "acorns." Hmmm. Now I don't know what to think. The woodpeckers where I come from live on insects. Acorns? I don't think so. Wait! You said this incident took place in California. That changes everything. Who knows what the birds out there eat. I'm surprised the tree wasn't stuffed with guacamole. With that new piece of information I think I know what bird created all those holes.

Your tour guide was right, Gus. Those holes were created by a woodpecker, an Acorn Woodpecker to be exact. Obviously, the bird gets its name from the habit of gathering acorns, not because it is in the shape of a giant flying acorn. I'm telling you that straight away because I may have told a lady the flying acorn story a while ago and somehow forgot to tell her that I was kidding. Oh, well. Woodpeckers are a good group of birds for new bird watchers to study. They are fairly easy to observe and typically aren't very shy, except for that crazy off-again, on-again Ivory-billed Woodpecker. And once you get past the annoying downy/hairy twins, most woodpeckers are readily identifiable. The well-marked Acorn Woodpecker is no exception to this rule. With its black body, red head-cap, white face, and crazy white eyeballs, it looks like a tiny Parisian street performer. But it's not their clownish looks that make these birds special. The Acorn Woodpecker's nesting and feeding behaviors are unlike any woodpecker you'll ever see roaming the streets of New Britain, Paris, or anyplace else.

While many of our Eastern woodpeckers like to keep to themselves, the West's Acorn Woodpecker is a major party animal. It lives, roosts, eats, and breeds in such rowdy groups that it would put any frat house to shame. The signature behavior of this bird is its lifelong obsession with acorns. During the fall they will spend their days gathering thousands of acorns and depositing them in what is called a "granary." While many other woodpeckers also stash food, only Acorn Woodpeckers will actually construct their own private storage container. During the long, boring winters the birds pass the time by drilling dozens of acorn-sized holes in a designated tree. They will fill these holes with fresh acorns as they become available in the fall. Knowing that many other animals, especially squirrels, also enjoy a meal of acorns, the birds are careful to pack the acorns in tightly so the squirrels can't pry them out. See, we are not the only creature that has squirrel issues. We are just the only creature that won't stop whining about it.

The life of an Acorn Woodpecker revolves around these granaries. The entire flock will guard and defend them from all comers. Some granaries have been used by these birds for generations, with as many as 60,000 acorn holes drilled into a single site. For the most part these granaries are located in trees. Fortunately for the trees, the birds only drill into the outer bark so most of the time they are not affected by the holes. If suitable trees can't be found the birds will use nearby fence posts, utility poles and even the sides of wooden buildings, providing the human owners with lovely natural air conditioning, which often isn't appreciated.

The breeding habits of Acorn Woodpeckers are also quite a bit different from those of our Eastern birds. While the puritanical Hairy and Downy Woodpeckers pair off in traditional couples, the Acorn Woodpeckers are living the life of hippies during the Summer of Love. This woodpecker often breeds in cooperative groups, in which the male birds mate with any or all of the females in the group. The birds share the same nesting cavity as well as the parenting duties. Up to three females may lay their eggs in a single nest, with several adults, plus the offspring from the previous year, taking turns incubating the eggs and raising the chicks. The chicks are fed insects at first. As they grow older the kids are given bits of nuts, including, of course, acorns, but also walnuts, pecans, and for the rich kids, macadamias.

Unfortunately for us, Gus, Acorn Woodpeckers have a rather limited range. Just about all of them live west of the Rockies. There is little chance you'll be seeing one in New Britain, CT, unless it happens to be on road trip, traveling in a flowered VW minivan, filled with leftovers from the Summer of Love.

Artwork by Catherine Clark

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