Avian Encounters at the Bernard Field Station

This semester, as a part of the Experimental Ecology Laboratory class at Harvey Mudd College, I had the opportunity to go to the Bernard Field Station once a week to observe its flora and fauna. There are so many amazing plants and animals, from the Wild Cucumber (Marah macrocarpa) with its spikey fruits to elusive coyotes (Canis latrans) that make themselves known with their yelps in the distance and their berry-filled scat.

But to me, the most alluring of all organisms in the field station were the birds. During my time observing in the field station, I saw so many different birds, including hummingbirds, woodpeckers, jays, mockingbirds, sparrows, ducks, and even hawks. The most noticeable of these birds was the raucous California scrub-jay (Aphelocoma californica), which was normally among the first birds I would notice upon entering the field station due to its blue coloring, large size, and frequent calls. They would usually sit at the very top of trees, surveying the surroundings, and scolding anything they did not like with their distinctive rising, metallic calls. They are the masters of the field station, taking all the best perching spots and bossing all the other birds around. I even saw one stare down a red-tailed hawk (Buteo jamaicensis) that landed on its tree once. The hawk left the tree first.

 

Figure 1: California scrub-jay (left) staring down a red-tailed hawk in its tree (right) [1]

Then there are the ground-dwelling birds, the California thrashers (Toxostoma redivivum) and California towhees (Melozone crissalis). These birds have remarkably similar plumage, with gray-brown feathers everywhere except for the distinctive red feathers on their bellies. Both of these birds feed on insects they find by rooting through leaf litter with their beaks. The thrashers are most often detected by song, which is a jumble of many different songs. They can then be identified by their distinctive curved beaks. The towhees are harder to find and are most often announced by the rustling of dead leaves. Their timid behaviors do not make them any less interesting, though. I once watched a trio rooting around in the leaves under a live oak for half an hour. They would mostly mind their own business, but sometimes one would rush over to a nearby white-crowned sparrow (Zonotrichia leucophrys) and scare it farther away before continuing their browsing. The most exciting part was when the towhees started chasing each other around. The pursuer would flick its tail up as it ran, displaying its red vent that is normally hidden by its more drab body feathers.

Figure 2. Field notebook entry about towhees chasing each other. [2]

By far the most colorful birds in the field station are the hummingbirds. While there are many species that can be seen in the Southern California region, I mainly only saw three species in the field station: the emerald-green pink-faced Anna’s hummingbird (Calypte anna), the orange rufous hummingbird (Selasphorus rufus) and its cousin Allen’s hummingbird (Selasphorus sasin), distinguished from the rufous only by its green back. The easiest way to spot these tiny birds is by ear – the loud whirring sound they make as they zoom past is unmistakable. It is often hard to identify which species you are looking at since they are usually silhouetted against the sky, and all three species can look to have pink throats. Hummingbirds are surprisingly aggressive: if two hummingbirds come to the same bush to drink nectar, they will usually end up chasing each other around, wielding their sharp beaks like swords.

 

Figure 3. Allen’s Hummingbird sitting on a branch. [3] 

One of the most exciting occurrences at the field station is the presence of a hawk. This is usually either the red-tailed hawk (Buteo jamaicensis) or Cooper’s hawk (Accipiter cooperii). Usually, the hawks were just passing by or stopped to rest in a tree for a bit. Even so, they have an immediate impact on the other birds: as soon as one of these birds glide into the field station, the usual chorus of songs of all the birds around immediately stops. The sudden silence at an active part of the day was one of the biggest indications that these large birds were looming over the field station.

Figure 4. Cooper’s hawk sitting on a branch. [4]

I have to say that leaving these birds was one of the hardest parts of going home for the semester because of the coronavirus. Just being able to cross the street and enter a place that felt like wilderness, so different from Harvey Mudd campus just across the street, and observe these captivating little creatures across the street was so amazing. I can’t wait to come back and have more incredible encounters next semester.


Media Credits:
[1] Photo taken by Marguerite Tate
[2] Photo of field notebook entry written by Marguerite Tate
[3] Photo taken by tdlucas5000. https://flic.kr/p/RrbNL5
[4] Photo taken by Mark Nenadov. https://flic.kr/p/XRwvRT