So these guys are a common occurrence on the hummingbird feeder, and they are well known for this behavior. I believe they are called Acorn Woodpeckers.
When I moved here earlier this year, it was absolutely hilarious to see this behavior. Previously, I've never seen anything but hummingbirds use their namesake feeders.
Edit: I updated the picture with a better resolution version! Original posted image is here:
Woodpeckers are omnivores, they will eat stuff like tree sap, similar to nectar in sugar content. Sapsuckers are related to woodpeckers and specialize in tapping into trees to drink the tree sap. So much to say it isn't that uncommon.
That's really interesting! It does make perfect sense. It's extremely common on my patio to see these guys doing this. In fact, I just got some high resolution images a few minutes ago to add to this post.
This one below is particularly funny, as a feisty hummingbird wanted a turn and they were eying each other.