Acorn woodpeckers of Angel Island
by
Angel Island is a park and nature sanctuary in the middle of the San Francisco Bay. It used to be an immigration and quarantine station and a military base, and now it's a park with interesting historical features. You can only get there by ferry, and while you can camp there, the only people who live there are park personnel and I guess maybe some people at the coast guard station.
In recent years, I've tried to go there in late December, during the intercalary interstitial interregnum. That's when it's the quietest and everything is green from the winter rains.
It's a great place to see birds. The ecosystem is not that different from San Francisco, so I tend to see a lot of familiar friends, like this California scrub jay.
During my last visit in December 2024, I identified a new bird. I first heard some unusual cries and I used Merlin Bird Sound ID to identify the bird by sound. Then when I had an idea of what it might be, I started looking around.
Sound ID said these red-hat wearing cuties were acorn woodpeckers.
I could see and hear that these were woodpeckers. They were definitely pecking at the tree, and like a lot of woodpeckers, they liked dead trees. But why, I wondered, were they called acorn woodpeckers?
I thought it might have something to do with all the coastal live oaks on Angel Island. It's more dense with them than anywhere else I've seen and maybe there's something about about that habitat that these "acorn" woodpeckers like.
Maybe whoever named them saw these oak trees full of acorns and named the woodpeckers after them. Maybe they eat some kind of worms that only live in acorns?
I was thinking about this for maybe an hour as I hiked along the ring road. Then I came across some dead trees that were much closer to the path, and this time the light was at a better angle for me to see, and I finally realized why they're called acorn woodpeckers.
Acorn woodpecker is not some kind of fanciful name. No, these woodpeckers make holes in dead trees and stick acorns in them!
Then, as if to politely help confirm my identification, one of the acorn woodpeckers flew to a branch right next to the granary tree and let me photograph it.
How cool are these birds? While I didn't catch any of them in the act, the Wikipedia page has some great photos of acorn woodpeckers carrying acorns in their beaks. Maybe one day!