Caltech Wildlife: Acorn Woodpeckers

Some of Caltech’s numerous, beautiful woodpeckers. Credit: Jieyu Zheng.

Woodpeckers are perhaps the most overlooked yet ever-present wildlife species on campus. Like the ubiquitous fox squirrels (a topic for another day), they are a daily sight if you know where to look. Every time I mention them to other Caltech students, the most common reaction is, “Wait, we have woodpeckers on campus?!” And I’ll nod slowly, like a long-time local: “Yes, we have at least three families of them.”

Among all woodpecker species, acorn woodpeckers stand out for their habit of drilling customized holes to store acorns—hence their name. If you look closely at the oaks and palm trees around campus, you’ll likely find thousands of neatly arranged holes, enough to trigger trypophobia. Yet, the woodpeckers remain busy, diligently collecting fresh acorns and shifting older ones into better-fitting holes as they dry and shrink. If Caltech’s founders had ever looked up, they might have found these birds to be a more fitting mascot— a native species to the West Coast with alert eyes shining in extreme engineering obsession.

So, where exactly are they located? I personally know of three active colonies: one near the Chen parking lot, another along the palm trees on Wilson, and a third in the central hub of the student dining area by Red Door. Each group appears to run its own “banking business” of acorns, feeding themselves as well as opportunistic squirrels and crows. Originally specialized in oak trees, these adaptable birds have expanded their service to palm trees, telephone poles, and even the seams of campus buildings. According to a longtime (20+-year) Caltech employee, the peckers once drilled holes between the bricks of Noyes, leading to water leakage issues.

To me, these birds are a simple constant source of joy and company. Every time I pass their territories, I would glance up, searching for their red-capped heads and white underwings. Their distinctive waka-waka calls, like a carpenter’s saw, guide my eyes to their bullet-shaped bodies darting between trees—they are always on a mission. Watching their persistent work reminds me to go into the lab and tackle my own research with the same determination.

The recent fires in Greater Los Angeles have destroyed homes, affecting many from the Caltech community, including the wildlife. When a tree near the Keck Institute and another on Wilson fell, they took with them the woodpeckers’ carefully drilled nests intended for spring hatchlings. Luckily, with their craftsmanship and resilience, the peckers have rebuilt new tree cavities in the remaining trees and are ready to bounce back.

I hope that after reading this, you, too, will take a moment to look for these tenacious creatures—our feathery and industrious campus companions.