This post is part of a series on the Wild Davis 2020 California Naturalist training course. This post is written by Wild Davis Graduate Teaching Assistant Chris Jadallah.
I am excited to spend some time at the Putah Creek Riparian Reserve for EVE 16: Wild Davis this quarter. Somehow I only made it here for the first time a few weeks ago, and I have already returned a few times since. Riparian areas are very special. They support so much biodiversity, serve an important ecological function as habitat corridors, and offer so much cultural, aesthetic, and economic value to people throughout the world. The parking lot is a short drive from my home near the edge of West Davis, just off of County Road 98 Right as the dark morning sky is starting to fade away, I head over with coffee in hand.
I arrive at the particular spot I selected within the Reserve at around 6:40 AM, just as the soft light of the morning sun officially rises up above horizon. The tops of the trees are bathed in a golden glow, but because the sun is still low, everything below remains in a cool light. A number of different trees make up the riparian forest towering over me, including valley oak, eucalyptus, black walnut, willow, and even what I think is an almond tree based on the fuzzy green fruits covering its branches. Perhaps it is a volunteer from a nearby farm which wouldn’t be surprising given that Putah Creek cuts through a landscape matrix of primarily agricultural land. The trees are filled with young green leaves that slowly drift in the very gentle breeze. The sky is clear but the temperature is brisk, about 48 degrees according to my phone. It’s chilly even under my fleece jacket, but in a refreshing way that reminds me of first coming out of the tent after a night camping in the woods.
I find a spot in the middle of the creek’s floodplain, and sit on the edge of a small cliff facing the water directly to the south. The ground is cold but mostly dry, except for the areas covered in vegetation where it is visibly damp, either from the morning dew or the storms that passed through the Sacramento Valley last week.
Before I can even settle into my spot, I am interrupted by a loud splash near the opposite bank. I see a plume of sediment underneath the surface of the water and immediately start scanning the area, thinking I might be able to find a fish. I was here last weekend and saw a largemouth bass hanging out near some large woody debris before swimming away. Immediately, I see a three foot long, slender object torpedoing from the area where I saw the splash away from me upstream. It disappears into the cover of an overhanging tree within a few seconds. My eyebrows furrow in incredulity and I stare in shock, thinking to myself, “What in the world?! That fish is HUGE. Did I really just see a three-foot-long fish? I’m pretty sure bass don’t get that big, could it be a catfish?” All of a sudden, it hits me – it was a river otter! My jaw drops in awe and stays that way for a good five seconds. I’ve only seen a river otter once before, when one was living at the Sutro Baths in San Francisco many years ago.
I’ve previously heard of river otters living in the Davis area, namely in the pools and canals of the Yolo Bypass, but I was definitely not expecting to see one today. I spend a good five minutes starting intently at the overgrown area where it disappeared, hoping to catch another glimpse, but alas, there was no sign of it. I begin to doubt myself, wondering if it was really just a big fish, so I pull out my phone to check the iNaturalist app and see if there had been any other observations of otters in the area before this. Lo and behold, someone recorded one in the exact same location less than two months ago. Just a few minutes into my observation, and my day was made!
It takes me nearly fifteen minutes to get back to more general observations of the site and stop thinking exclusively about the otter. I re-focus, and spend some time paying attention to some of the geomorphological and hydrological properties of Putah Creek. The water is about five feet away in front of me and below me, my feet hanging over the exposed earthen bank. In the area directly in front of me the creek is clear and fast-flowing, ranging in depth from about six inches to two feet. Medium-sized, multi-colored gravel make up the creek bed. Periodically, a small piece of algae or a leaf quickly floats by. About twenty feet across the creek is a marshy island, from where I assume the otter was either resting or sleeping before I accidentally disturbed it. The island is covered in short bunch grasses that are mostly brown, but with some pockets of green growth, as well as a few willow saplings.
Upstream, the channel narrows, so the river seems deeper and faster. In the middle of the channel, the water ripples due to some overhanging vegetation that dips into the surface. Downstream, the channel widens and the water slows. Along the bank, which curves slightly south, the water appears to still be moving relatively fast. It’s interesting to notice how these physical components of the creek play off each other. There is a clear relationship between channel width, channel depth, and flow, and this undoubtedly has an effect on the richness and abundance of aquatic life.
As I record these general notes, I periodically look back toward the spot where the river otter swam, and spend a few long seconds scanning in the hopes that it is still there. As I’m doing this, a female duck comes into view from upstream, slowly paddling along with the flow of the water. It swims toward the edge of the marshy island and begins foraging in the semi-aquatic plants, filtering water through its beak. A few seconds later, I hear a distant quacking that grows louder and louder until a male duck flies toward her from above, landing in the water with a loud splash. She immediately flies away and out of view upstream, and he takes off again to follow in a flurry of commotion.
After the disturbance, the scene becomes calm again. Just because it’s calm, however, doesn’t mean it’s quiet. The babble of the creek provides a constant backdrop to incessant bird calls. Directly across the creek from me, I hear the songs from what seems to be several birds of unknown species. Behind me, I hear the periodic and distant coos of a dove. The sharp cry of a red-tailed hawk pierces the air. Far away, the faintest sound of the occasional car speeding by on the county road comes into earshot. I could get lost in the sounds.
I take some time to observe more directly around me. Immediately to my left and right, and all behind me toward the middle of the floodplain, are young, leafy mustard plants between a few inches and about three feet tall. While a few are starting to flower with tall stalks of yellow blooms, most are still in the pre-flowering stage. Interspersed amongst the mustard are grasses of similar height, covered in stalks of young green seeds. To my right are some small brown mushrooms growing from the soil at the base of these plants. Walking trails criss-cross the floodplain, and I am surprised that I have not seen a single person yet given that these trails are usually quite popular.
It is 7:30 AM now, and as I get ready to walk back to the parking lot, I notice that the glow of the sunlight has lowered to capture more than just the tops of the trees. Downstream, it is even shining on the water surface, causing water vapor to rise in wisps. I’m excited to return to this place and continue seeing how it changes over the next few weeks – I have so much love for where I live.