A New “Tree” for Woodpeckers

A yellow-naped woodpecker is hard at work.

A yellow-naped woodpecker is hard at work.

Nothing beats natural behavior. Allowing birds to use their evolved traits, behaviors, and abilities usually results in a healthier bird in both mind and body. We encourage natural foraging behaviors by hiding earthworms in loose soil for the kiwis to hunt. We do bug scatters in the diving duck aviary for the ducks to dive for (it is so cool to watch!). And we try to make available various nesting material the birds would look for and use in the wild. Hummingbirds get spider webs, weavers get thorny twigs, and woodpeckers get…hmm…how do you replicate the tall, thick, dead trees most woodpeckers prefer to use in the wild? The San Diego Zoo’s Horticulture department does such a good job at keeping the trees alive and healthy that there are not many dead trees available. Not to mention that it would be difficult to actually move those trunks into the exhibit!

Enter the cork nest! The ingenious box was developed by curator Peter Shannon and his team at Albuquerque Biological Park. The nest box has plywood sheets on the top, bottom, and three sides. The fourth side is open, exposing the cork. The idea is that the cork is hard enough to provide the birds a tough substance to chip away at but is soft enough for them to still make progress. Here’s a photo essay and video of what happened…

On February 3, 2014, I used a tool to make a small indent in the hard cork on the front of the nest box and installed the box in the yellow-napped woodpecker’s Picus chlorolophus exhibit, which is just up the hill from the turtle exhibit on Tiger Trail.

#1: On February 3, 2014, I used a tool to make a small indent in the hard cork on the front of the nest box and installed the box in the yellow-napped woodpecker’s Picus chlorolophus exhibit, which is just up the hill from the turtle exhibit on Tiger Trail.

Within hours, the male was clinging to the front of the nest box and was working away at the starter hole I had made! You can see that the woodpeckers are much better at making circles than I am…how embarrassing.

Within hours, the male was clinging to the front of the nest box and was working away at the starter hole I had made! You can see that the woodpeckers are much better at making circles than I am…how embarrassing.

After congratulating myself for thinking about making the starter hole, I walked into work on February 9 to see this. Hmm, obviously I didn’t put the starter hole in the right place and the birds had come up with their own location.

After congratulating myself for thinking about making the starter hole, I walked into work on February 9 to see this. Hmm, obviously I didn’t put the starter hole in the right place and the birds had come up with their own location.

By February 16, though, the birds had come up with an even better spot!

By February 16, though, the birds had come up with an even better spot!

 A week later, the three holes look like a surprised cork ghost...

A week later, the three holes look like a surprised cork ghost…

 ...and by March 16, a scared cork ghost!

…and by March 16, a scared cork ghost!

It has been such a joy these past few weeks to see both of the woodpeckers engaging in their natural nesting behavior. At the time of this writing, the bottom hole is the most extensive cavity that reaches to the very bottom of the nest. The upper right hole is also large but does not extend or break through to the bottom hole. And the top center hole—the one I helpfully started for them—nothing. I think they just worked on it to be nice.

The video below is not the up-close-and-personal video I’ve tried to show in the past. But I think it is great in that it was taken from the guest walkway and is exactly what observant—and lucky—guests might be able to see for themselves! In the video, the woodpecker is “corkpecking” and chipping away at the material. Later in the day, I was delighted to see the female’s pointy beak emerge full of loose bits of cork. She spat the cork out, ducked back into the nest, and emerged seconds later with another mouthful of excavated cork. How cool!

Woodpecker Video

Mike Grue is a senior keeper at the San Diego Zoo. Read his previous post, A Trick up Her “Sleeves.”

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