The early morning sun cast long shadows on the hills in Portezuela. The Scrub Oak shadows were warped and elongated, making them look like giants. I scrambled across a small drainage while keeping a wary eye on the vegetation to make sure I was not diving into Poison Oak. I was out looking for a new pair of Island Scrub-jays who we have seen “acting nesty” in this area. I headed to where I saw them six days ago, hoping they would still be hanging around. I scanned the flat and gentle slope in front of me and saw nothing. It was barely seven o’ clock and a warm breeze rustled the leaves of trees and shrubs. I hadn’t seen a jay yet. Perhaps they knew something I didn’t. I wandered the hill, ears alert for any sound that might give me a clue to where these birds were. My eyes constantly scanned for movement.
Occasionally, I closed my eyes and just listened. Though the jays weren’t moving about, a concerto of bird song enveloped me. Spotted Towhees—perhaps the most abundant bird on the island—sang from nearly every aural direction. Bewick’s Wrens zoomed around and crooned from the tippy-tops of snags. Blue-gray Gnatcatchers “zee zee zee zee zeeeed” frantically, zipping from branch to branch. The leaves rustled, the breeze whispered, and the creek rushed behind me. Suddenly, I heard it—a single jay call, almost a scream. My head snapped up and I saw the silhouette of a Scrub-jay bobbing in the top of a large Scrub Oak 150 meters away. I began my quest to find their nest.
When I got to the tree, I dropped my pack and crept silently towards an opening in the branches. I could hear the pair rustling around in the protected sphere under the canopy. I peered through the branches and watched them hopping around from branch to branch, picking off bark and munching the goodies underneath. I might have been watching them for a while before they flew off to their possible nest site, so I began to take territory points on the male, AP/URB, a second year born on the plot in a different territory. I started the 5-minute countdown timer on my watch and took a mental note of where AP/URB perched so I could go back and GPS it later. I watched them forage together. Every so often they perched on the top branches of the tree and he brought her a morsel to fed her. Every 5-minutes, my watch beeped and started the countdown again. Each time, I took a mental note of his location until I had five territory points.
They continued to forage until finally, I heard the satisfying “craaack” of a stick breaking off a bigger branch. I swung my gaze to the female, PGO/AP, and she had a fresh stick in her bill and she was about to break off another one. She took the sticks, each about the dimension of a pencil, and flew up to the top center of the tree. Lucky me, their nest is in this tree! Usually, you watch the birds pop out of the chaparral with material and then fly many meters until you can’t see where they go or they fly behind a ridge and you have to follow them and wait for another material carry. It can take hours of careful observation or random vegetation searching to find a nest. Thankfully, the male began carrying sticks to the same part of the tree. I was surprised that they were building the nest right in front of me. I’m sure they knew that I was there because they had acknowledged my presence with chuffs and grunts and the occasional curious head cock. They are a new and young pair; perhaps they haven’t learned that when they see a human it means their nest is soon to be discovered. I let them build for a while so I didn’t disturb them. When they seemed to take a break, I took my nest pole and snuck into the foliage.
The nest was roughly 3.5 meters high in the oak, hidden from the top and only barely visible from below. The birds had woven the sticks into a round platform in the crux of a branch. Next, the birds would add smaller sticks to the inner bowl, and then soft lining in a neat cup. I took a GPS point directly below the nest, took notes on the shape, height, and progress of the nest, and slipped out of the tree again. The birds took little notice, and continued to build their nest. I flagged a nearby tree and took off again to look for my next pair.
Nest found. Satisfaction. When you find the nest of a new territorial pair, you get to name the territory and therefore the birds. Since the territory is in Portezuela, the beer-themed plot, I named the territory Lagunitas after a Marin County brewery. I checked the nest today and there were no birds around. Usually when you go near a nest, the pair flies in and “chuffs” at you—a sort of grunting “ruh ruh”. I was worried that the nest had been abandoned, but I later saw them carrying lining material (fine grasses) to the tree. Hopefully they will fledge young, although reproductive success on the island is low. Of approximately 141 studied nest attempts last year, only 18 nests fledged young. The others were lost to predation, abandonment, or weather. The idea of so few nests putting young into the population is startling, but once the birds make it past the fledgling stage they have much higher survival rates. Island Scrub-jays can live a long time compared to smaller birds; some have been known to be at least 16 years old.
I will follow this nest until fledging (or until it fails) and let you all know how it goes.
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