May 29, 2006

Acorn Woodpeckers

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© Jim Pankey -- click picture to enlarge

-- click note to play

A friend of my long time friend in Cherry Valley, California, took this magnificent picture of Acorn Woodpeckers adding acorns to their granary. In my opinion this picture gets right to the reason that Acorn Woodpeckers are such interesting birds.

To me, Acorn Woodpeckers with their sharply marked faces look like the classic clown bird, and their flight pattern reminds me of a pop-up toy. They are a communal bird who will create huge granaries of Acorns in dying trees or as this picture shows, in telephone poles. Because they can create enormous caches for their treasure (one study found a cache of 60,000 acorns), they work together to protect their horde. This cooperative behavior extends to their nesting and parenting behavior as well. From The Sibley Guide to Bird Life and Behavior:

Polygynandry In a very few species, individual females may end up paired with more than one male, and males may pair with more than one female. This complex breeding system, called polygynandry, has been best studied in a European songbird called the Hedge Accentor (Prunella modularis). In North America, Smith's Longspur (Calcarius pictus) and perhaps a few other species are polygynandrous.

One very well studied species has been described as "opportunistically polygynandrous." The Acorn Woodpecker has a complex mating strategy in which birds live in groups (primarily to defend stored acorns) and several females lay eggs in a single nest. These females compete with each other with regard to the number of eggs each lays in the nest, even to the point of throwing their rivals' eggs out of the nest. Male compete with each other for access to the females, and if a dominate male is removed from the group during egg-laying, he may throw all the eggs out of the nest upon his return and force everyone to start over again. Once the clutch is finally laid, all group members help raise the young.

So where can you find these guys? You can see Acorn Woodpeckers in the oak covered hills of California. I can't help but think I've seen these exact birds and this exact telephone pole on one of my walks with my friend through Bogart Park. In the Monterey Bay region, you can find any number of Acorn Woodpeckers in the woods at Elkhorn Slough. And although, they are not common in the Portland area, you can reliably find a small colony of Acorn Woodpeckers at Pacific University in Forest Grove just west of Portland.

BTW: You can buy the song with the calls of the Acorn Woodpeckers from here. And to see more of Jim's pictures, you can go here.

Update: Here's a couple more of Jim's Acorn Woodpecker pictures you really should see (here and here).

Posted by Mary at May 29, 2006 02:02 PM | Entertainment | Technorati links |
Comments

I didn't even know the word Polygynandry nor that its behavior existed in birds--but observing these acorn woodpeckers and the way they were caring for the young in the nest seemed an oddity. I couldn't believe it at first, but there were actually 7 adults tending and one in a tree guarding. I hope to return there to catch them as they leave the nest, but that will probably not happen this year, as I am traveling East (to St. Louis, MO) for a couple of weeks.
I'm happy someone takes interest and expands my knowledge. I won't forget it. Thanks for posting my photos.

Jim

Posted by: Jim Pankey, USN (Ret.) at May 29, 2006 04:02 PM

You're right -- beautiful
picture. I'm limited by my
point & shoot box -- but did
finally get a picture of a
huge ponderosa trunk riddled
with acorn holes. Take a
look!

Granny J

Posted by: Granny J at June 4, 2006 08:13 PM