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California Natives - Fauna Nature

Our Closest Neighbors Are Birds

Several avian neighbors regularly flout our home owners association rules by installing custom built additions on our house from late spring into the summer months. Of course our human neighbors are not aware of the nests and even if they were, it is against the law to move or destroy an active nest. While the three species discussed here are considered native to and common in California, each one ranges, to varying degrees, far beyond the state.

Photo of a Bewick's wren perched on a backyard railing
A Bewick’s wren perched on a backyard railing

A Bewick’s wren (Thryomanes bewickii) couple made a nest on a side of our house at a spot where the wall, roof and eaves intersect to form a small cavity. One morning I noticed two birds with white eyebrows making numerous trips from south to north. They hopped with brisk intent along a low brick and embedded iron railing wall that borders our patio, stopping every few feet to scan their surroundings. On almost every trip in the northerly direction, one or both wrens carried an insect in its beak. Upon reaching a particular spot along the wall he or she would gaze up at an opening that never previously looked like a nest box to me, take a brief flight up to the entrance and disappear inside. I have not attempted to view the chicks at their nest because to do so would require a way to see into a dark space that is enclosed on all but one side. From the outside, this inadvertent nest box looks like a good place to escape the notice of predators.

Still common in the western states, the Bewick’s wren population has declined significantly in the east. The species’ decline has been attributed to both pesticides and the aggressive nesting behavior of the House wren, a related but more aggressive wren that is known to commandeer nests and destroy the eggs and young of the Bewick’s wren, as well as those of other birds.

 

 

A resident House finch (Haemorhous mexicanus) couple nested on the western wall of the house. (The Bewick’s wren nest is also located along this wall, about five meters to the north.) The nest sits on a ledge underneath the roof overhang.

Photo of the House finch nest
The House finch nest

Finches have been nesting here for at least two years. The nest was, still is, visible from inside the house, through a window. Sometimes the female can be glimpsed at the nest with her head bobbing about in a way that suggested she might be feeding nestlings.

About six weeks ago I suspected they were feeding nestlings, but confirmation would require climbing up a ladder and peering into the nest. Being curious but reluctant to be a source of stress, I put it off.  One afternoon I looked up through the window at the nest to see a California scrub-jay fly to the ledge and start pecking at something in the nest. The parents were not around. Not being one to interfere with nature, I ran outside waving my arms and yelling. At this the jay flew to a nearby tree and the parents returned a moment later, one perched on a nearby railing and the other in a tree near the jay. Neither approached the nest, probably because I was in the way. The jay made another approach at the nest, but turned back. Between the unidentified earthbound object’s interference and finch parents’ presence, the jay determined that it was no longer going get a quick meal and flew away.

I  pulled the ladder out of the garage. At the nest I found two very young and awkward-looking nestlings covered with fluffy down. The one closest to me opened its mouth, as if to receive food; it appeared to be unharmed. I could not determine the status of the second nestling as its head seemed to be tucked into its body, as if in sleep. I left the scene so the parents could get back to their young. An hour later I stopped at the window to see the female tending the nest.

 

 

Photo of Mourning Dove fledglings on a ledge under roof eaves
Mourning Dove fledglings on a ledge under roof eaves

The Mourning dove (Zenaida macroura) ranges throughout most of the United States and into parts of Canada, Mexico and Central America. I discovered a pair of fledglings in a nest on the eastern side of our house when I walked  underneath the nest and a parent flew out, causing alarm for all concerned. At the parent’s sudden exit, a fledgling in the nest lost its perch and tumbled out. The young bird’s feathers were not developed enough for flight, but it was able to flap enough to glide into a landing. I picked up the fledgling with its wings folded close to the body and put it back in the nest. When I climbed up the ladder to take a photo later in the day, I discovered a second, smaller fledgling. The typical clutch size is two eggs.

The following afternoon I was working in the garden within sight distance of the nest when the larger of the two fledglings once again jumped, flapped and glided out of the nest when a parent took off. This time it was far too fast for me to catch and return even though it still could not fly. Accompanied by both parents from above, it hopped and flew short distances and disappeared among a tangle of trees in a neighbor’s yard on the other side of the decrepit iron railing that serves as a border around our property. In researching the species’ behavior, I learned that the male will feed a fledgling on the ground for up to two weeks, until it is ready to fly and be on its own.

The oldest known Mourning dove lived to over 30 years of age. Because they are fairly long-lived, the parents of the young pictured here may be the same pair that has nested at this spot every year since 2012. The couple tending this nest started off their courtship in the spring. I think that they have already produced a new brood because a parent is sitting on the nest now at all times. (The species is known to produce up to six broods per year.) During courtship they perch on the railing along the perimeter of our backyard and perform a back-and-forth dance that involves quite a bit of grooming. The male grooms the female, then she side-steps away and he follows her. When the male stops his pursuit, she returns and begins grooming him. Then the routine begins again. The male has a few spots on the railing where he likes to sit and coo his plaintive lament. To the human ear it may sound romantic or mournful, until one learns that this is a territorial call letting other males know to stay away.

Categories
California Natives - Fauna California Natives - Flora Nature

Backyard Monarch Project: A Year Later

I am so behind on planned posts! I have a piece of digital artwork featuring the western tiger Swallowtail butterfly that I want to include in a post that discusses the Swallowtail in some detail, but I am only about halfway through the layers that I am using to create a composite image.

So, I decided to post an update on a project I started about a year ago, something that I could knock out with a smaller time investment, an update on my backyard milkweed and monarchs project.

In this post from July 8, 2016, I documented the first appearance of a monarch butterfly in our yard. She showed up a few months after I planted some  Narrowleaf milkweed (Asclepias fascicularis), a native in our area that is currently in bloom in places along the Albertson Fire Road and on some of the single track trails in the area. I should point out that the milkweed appears to be competing for space, moisture and pollinators with the non-native mustard plants that turn the hills a glorious yellow in the spring. I have taken to pulling out encroaching mustard plants during my hikes, but only when there are no mountain bikers or hikers around because most people will not understand what I am doing–it looks like I am destroying nature instead of trying to give the Narrowleaf a better chance to fight against what is, in the Santa Monica Mountains, an invasive weed. Certainly during my first spring here, I had no idea that the plant that made the hills so yellow in the spring and attracted nesting Red-winged Blackbirds in quantities up on the Autumn Ridge trail was a problem for native plants.

Now, on to the actual update. Most of the Narrowleaf species planted last year in our yard have returned, but they remain small and it is not clear whether they will thrive. Even the tallest among them cannot sustain the voracious appetite of one caterpillar through five instars. From what I have observed on the mountain trails, it can take a few years for the Narrowleaf to establish itself to the point where it becomes a robust and tough plant that can grow tall and produce many leaves and flowers.

In the meantime, I continue to cultivate a fast-growing, non-native that is not invasive: Asclepius physocarpa aka Balloon Plant or Family Jewels. This spring six monarchs have already reached maturity on these plants. Here is a member of the two or three caterpillar generations currently developing on the plants.

Photo of a Monarch caterpillar "buzz-sawing" its way through an Asclepias physocarpa milkweed leaf.
A Monarch caterpillar “buzz-sawing” its way through an Asclepias physocarpa milkweed leaf

This morning a female visitor added a new generation.

Many, many eggs to lay before she rests
Many, many eggs to lay before she rests

 

 

 

 

 

 

 

 

 

 

In closing, something native but completely different, now blooming in our front yard: the fragrant Salvia clevelandii.

 

Categories
California Natives - Flora Nature

Ceanothus (California Lilac)

Photo of Ceanothus on the Mesa Peak Trail in the Santa Monica Mountains (March 2017)
Ceanothus on the Mesa Peak Trail in the Santa Monica Mountains (March 2017)

Last spring I started replacing non-native with native California plants around our house. I started with a couple small plots front and back and a slope on one side of our house. This spring I expanded this effort to include additional areas in the front and back yards.

The plants I put in this spring included a Ceanothus shrub, a hybrid known as Ray Hartman. I planted a Ceanothus because 1) several species of the shrub grow along nearby mountain trails where I like to hike; 2) it is an important pollinator shrub; 3) it has nice flowers in the spring, or summer depending on the species; and 4) once established, it requires no summer water. In the course of writing this article, I discovered yet another good reason to include a Ceanothus or two in a native plants garden: after they are broken down in the soil, the shrub’s spent leaves become an good nitrogen source for neighboring plants.

About 50-60 species of the genus Ceanothus have been identified. Roughly half of these are native to California. This genus of shrubs or small trees is a member of the of the Rhamnaceae family. Ceanothus has evolved to survive in low nitrogen soil despite the fact that nitrogen is an important nutrient that it requires. How did it evolve to survive in a soil that is low in nitrogen? Going back some millennia, the genus started trading favors with a bacterium in the genus known as Frankia. The partnership turned out to be mutually beneficial. Each partner had an intrinsic limitation or environmental reality that it was facing and required an adaptation in order to survive. As it turned out for these two, a shrub and a bacterium, a symbiotic exchange was the answer.

Frankia lacks the chlorophyll found in green plants, so it cannot photosynthesize energy from the sunlight but it is great at nitrogen compound conversion. The genus Ceanothus lives in nitrogen-poor soil and yet it inexplicably, at least by me, skipped the chapter on nitrogen chemistry. As a result it cannot get enough usable nitrogen on its own but, it is great at photosynthesizing energy, or sugar, from sunlight. The partners discovered, probably very slowly, that an even trade was the best strategy for continued survival.

Filament-shaped Frankia absorb nitrogen from the atmosphere and convert it into a form that the Ceanothus’ roots can use. According to Peter del Tredici, a senior research scientist at the Arnold Arboretum, as the shrub grows, the bacteria infiltrate the roots and flood the root with hormones to prompt the plant to create root nodules (A Nitrogen Fixation: The Story of the Frankia Symbiosis, 27). Within the root nodules, Frankia convert nitrogen into a root-friendly component that the shrub can use. In return, the shrub photosynthesizes and shuttles sugar down its roots to the bacteria. Plant and bacteria evolved together. They established a niche within and probably have had a formative impact upon the ecosystems where they are found, because other plants benefit from their alliance. The late Bert Wilson of Las Pilitas Nursery included several nodule photos with a moving description he wrote about Frankia’s purpose within and benefit to the ecosystem it inhabits.

Research has shown that leaves shed by the Ceanothus plant are broken down by bacteria other than Frankia in the soil. One of the byproducts of the Ceanothus leaf’s return to basic elements is a form of nitrogen that is accessible to other plants that do not have a direct symbiotic partner like Frankia–but they do have a mighty nitrogen-fixing team as neighbors.

Photo of Lupine growing beside the Mesa Peak trail in the Santa Monica Mountains (March, 2017)
Lupine growing beside the Mesa Peak trail in the Santa Monica Mountains (March, 2017)

Lupinus aka Lupine is a wildflower that we have seen in abundance this spring because of the generous amount of rain southern California received during the winter. I have a couple of these plants in my garden, but with adequate winter rains they are ubiquitous in spring, appearing not only on mountain trails but in a triangle of dirt beside the entrance ramp to a freeway, for example. Lupine works with a nitrogen-fixing bacterium as well, not a Frankia bacterium but one in the genus Rhizobium. For more about the nitrogen-fixing plants (and their partners) of California read Bert Wilson’s There are Many Higher California Native Plant Species That Fix Nitrogen.

Finally, understanding the capability of plant and bacteria partnerships that fix nitrogen may present human beings with the opportunity to rely less on fertilizer to feed a hungry world. Fertilizer pollutes our water and soil and the effect is cumulative. Nitrous oxide, a byproduct of nitrogen fertilizer, is a potent greenhouse gas that contributes to climate change. Fortunately for all living things on the planet, there are scientists who are researching how we might turn to nitrogen-fixing on a large scale and farmers who are willing to test the hypothesis that less (fertilizer) might be just as effective, and thus better, than more.

Categories
California Natives - Fauna Nature

Pacific Gopher Snake – Pituophis catenifer catenifer

During the past month I have encountered the Pacific Gopher snake (video) three times while hiking or running on the fire roads and single-track trails near my house. Each sighting was in a different location. The second and third snakes appeared at least one mile or more from the previous sighting so they were probably three different individuals.

The Pacific Gopher is very common snake in California. Most active during the day, it will hunt on very warm evenings. Its prey includes small mammals, lizards, other snakes and birds. Birds? Yes, the Gopher snake can climb trees. I once witnessed one drop casually from a low hanging tree limb onto the ground. Some snake species, the Striped Racer for example, can move so fast that it can be difficult to identify them. The Gopher snake is slower moving, taking a relatively leisurely pace for a snake. The one Striped Racer I have spotted so far was so quick to slide down a bank into the safety of a tangle of sage beside the trail that I only had a second to see the second half of its slender black form with horizontal yellow stripes.

Any snake encountered on the trail (or off-trail) is a resident of the natural world around us and should be given plenty of space and respect. Other common snakes found on the trails include the Western Rattlesnake, Kingsnake and Striped Racer. These snakes have evolved within and are perfectly adapted to southern California’s Mediterranean ecosystem. The particular misfortune of the Gopher snake is that humans often do not know the difference between the Gopher and a Western Rattlesnake. The easiest way to tell the difference is head shape. The head of a rattlesnake is triangular  while the head of the Gopher is slightly oval and slim by comparison.

Many people have an aversion bordering on phobia to snakes. This phobia is something that I have been thinking about lately, probably because I do not seem to possess it. I do have a fear of rattlesnakes in the sense that I do not want to accidentally stumble upon one, or find one taking up residence in my house, or get within striking distance (half the length of the snake itself), but that seems rational; a bite is not only painful, it can be life-threatening. What puzzles me is when there is a fear of or extreme aversion to all snakes, including those that are non-venomous. Maybe it depends upon one’s familiarity with different snakes species, that is, being able to identify a snake when encountered, or simply knowing the physiological differences, e.g., the shape and width of head, between a venomous and non-venomous snake.

It could also be due to to something known as an epigenetic rule. Epigenetic rules, refer to “…genetically based neural wiring that merely predisposes the brain to favor certain types of action.” Following this theory, humans may be predisposed to certain genetic instincts, such as a fear of snakes, although that instinct may remain unexpressed, as in my case.