We have all heard about hummingbirds and their ability to hover and fly backwards. These tiny feathered jewels are a delight to observe. They are birds of the New World, and I feel sorry for people living in parts of the world that don't have hummingbirds. Where I live, on the coast of Northern California, the resident hummers are Anna's hummingbirds (Calypte anna). We get the occasional Rufous and Allen's hummers (Selasphorus rufus and S. sasin, respectively) passing through on their migrations, but the Anna's are here year-round. We have front-row seats to watch their mating displays, and I know they must be nesting nearby even though I've never managed to locate a nest.
The other day, while sheltering in place at home, I went outside to photograph birds. The Anna's hummers were putting on quite a show. The males have been displaying since February, flying straight up-up-up and then plunging into a J-shaped dive near an observant female. At the bottom of the dive the male uses his tail feathers to create a sharp and very loud chirp. When this occurs about a meter from your head, it sounds like a pistol shot. Trust me on this.
Anyhow, that day I was lucky and captured some shots of a male Anna's hummingbird hovering in place. These aren't National Geographic quality photos, but then again I'm not a National Geographic-caliber photographer. For anyone who is interested in such details, here are the EXIF data:
300mm f/4 lens
1/2500 sec at f/4
At a shutter speed of 1/2500 sec, you can freeze even the movement of a hummingbird's wings. You can see very clearly that although the bird's wings are moving, his head remains perfectly skill and his position doesn't change at all.
A hovering hummingbird moves its wings in a figure-8, similar to the sculling motion of a skilled rower. If you use your imagination a bit you can see the rotation of the wings in this set of photos.
Given the mandate to shelter in place at home, I don't know how many of the upcoming morning low tides I'll be able to explore. On the one hand, I'd be by myself, not risking exposing anyone to any germs I might be carrying. On the other hand, staying home means, well, staying home. The tidepools are calling to me, but this year I might not be allowed to accept the invitation. All for the greater good, right?
We Californians are all under a state-wide mandate to stay at home, to minimize the spread of COVID-19 this spring. School hasn't been cancelled, but all classes have converted to distance learning. I had four days to figure out how to deal with that. Fortunately we are in spring break this week, which gives us all a little bit of a breather. I'm going to use the time to catch up on grading and plan for the second half of the semester.
The marine lab is also closed for business. Only essential personnel are allowed to be there. The term 'essential personnel' includes people whose responsibilities are animal husbandry. Since animals will die if I'm not there to feed them, I have met that criterion for essentiality. That's not a word, but you know what I mean. With so many fewer than usual people at the marine lab, there's a lot more wildlife activity. A few days ago I saw a long-tailed weasel (Mustela frenata) chase down and capture a young brush rabbit. I just barely had time to catch a quick shot with my phone.
The most noticeable thing, though, is the increased birdsong. The sparrows, finches, red-winged blackbirds, mallards, doves, towhees, and hawks are all making a lot of noise. The barn swallows (Hirundo rustica) returned to the lab on the 21st, right on time! Maybe this year they'll have a more successful nesting season than they did last year.
Yesterday I witnessed something I'd never seen before: a territorial dispute between a black phoebe (Sayornis nigricans) and a barn swallow. The fact that I had never seen it before in no way implies that it happens only rarely; maybe I've just never paid that much attention to these things before, or they've never happened while I've been around to watch.
Here's the story, in a series of snapshots.
Prologue. The barn swallow (H. rustica) is perched on one of the outdoor light fixtures. The phoebe (S. nigricans) swoops up from below.
The swallow takes to the air, only to be divebombed by the phoebe.
The swallow retreats. . .
. . . and the phoebe perches, triumphant, on the rain gutter.
The entire altercation lasted maybe as long as four seconds. I didn't see where the swallow flew. The phoebe remained on the rain gutter for about a minute or so, then took off over the meadow. Perhaps it has a nest somewhere nearby and was defending it. Both species build mud nests on cliffs and buildings, so these birds could be competing for nest sites. Or maybe phoebes just don't like swallows. Either way, this was the sort of interaction that I don't notice when there is a lot more human activity at the marine lab. Nature has a way of re-asserting herself when humans are removed from the scene for even a short period of time.
Of course, sea anemones don't have faces. They do have mouths, though, and since a mouth is usually part of a face, you can sort of imagine what I'm getting at. The sunburst anemone, Anthopleura sola, is one of my favorite intertidal animals to photograph. Of the four species of Anthopleura that we have on our coast, A. sola is the most variable, which is why it keeps catching my eye.
This afternoon I met the members of the Cabrillo College Natural History Club for the low tide at Natural Bridges. Here are some of the A. sola anemones we saw.
Such an amazingly photogenic animal, isn't it?
This past Fall semester the NHC went tidepooling at Pigeon Point. Today we were at Natural Bridges, and later in the spring we are going to Asilomar. I didn't intend it, but this school year the club is getting a look at three very different intertidal sites.
It's no secret that I love pelicans. I love watching them soar low over the waves, where they are truly in their element. I love watching them plunge from the air into the water and then bob right back to the surface, because unlike their cormorant relatives, pelicans can't fly underwater. And I love watching them plunk around on land, where they are dumpy and awkward but still somehow elegant.
The other day I ventured out between storms to photograph birds. As per usual I ended up down at Natural Bridges, where pelicans were hanging out on the last remaining rock arch. They were well within the reach of my long lens, so I took a lot of photos.
The best photos I got were of a subadult pelican coming in for a landing.
Landing gear down!
Decreasing air speed:
And. . . touchdown!
A job well done!
The youngster managed a safe landing without knocking one of its compadres into the water. That isn't always the case--those wings can do a lot of damage. But the three adult birds on the left hardly seemed to notice, which means the youngster has learned how to stick the landing without disturbing everyone else in the vicinity. I'm sure that's a lot easier said than done!
Autumn is migration season in California. We all know that, in the northern hemisphere, birds fly south for the winter and return north for the summer. And indeed, this is a very good time to go bird watching along the Pacific Flyway, as migrating birds stop to rest and feed at places such as Elkhorn Slough. Here in Santa Cruz, autumn is punctuated by the return of monarch butterflies (Danaus plexippus), roosting in eucalyptus trees at Natural Bridges State Beach and Lighthouse Field.
Since 1997 the Xerces Society for Invertebrate Conservation has been tracking monarch sightings on their migrations between the western U.S. and Mexico. They conduct a volunteer butterfly count every Thanksgiving. More recently, community science data sources such as iNaturalist provide much of the information.
This morning, before it got warm, I went to Natural Bridges to see how the monarchs were doing. I wanted to photograph clumps of butterflies dripping from tree branches. It seemed, however, that there aren't as many butterflies as I remember from previous years. The clusters were not nearly as large or as dense as they should be. And the data shown in the figure below do demonstrate a precipitous decline in monarch since 2017. We're still a couple of weeks away from this year's Thanksgiving count, and there is still a chance that the butterflies might arrive in larger numbers.
Trained observers know how to estimate the number of butterflies in a cluster like this. The numbers of butterflies at various roosting sites are aggregated to assess overall population sizes.
This morning I did see one butterfly that had a tagged wing. It was wearing a green Avery round sticker, with some writing in what looks like black Sharpie. The color of the sticker was very close to the green of the surrounding foliage, so I wasn't even able to see the sticker until I downloaded the pictures from the camera.
At first I thought the tag resulted from an official scientific project or undertaking, but it turns out that anyone can tag a monarch. The tags are used to track migration of the butterflies. There doesn't seem to be a central depository of tags and their origins, so knowing the color of the tag doesn't tell me where this particular butterfly came from.
Once the sun hits the butterflies and they begin to warm up, the clusters start breaking apart. Butterflies open and close their wings, exposing the darker dorsal surfaces to the sun and warming up their flight muscles. Sometimes they dislodge one another.
On a cool morning like this, many of the butterflies that fell out of the clump couldn't fly yet, and landed on the ground. The boardwalk is perhaps not the safest place for a butterfly to wind up, but at least in a monarch sanctuary such as Natural Bridges the visitors are knowledgeable and look out for the butterflies' safety.
As I wrote before, the butterflies we see at Natural Bridges this year were not born here. This means that their survival to this point has depended on healthy conditions in the Pacific Northwest and the western slopes of the Rocky Mountains, where they lived as caterpillars and emerged from their chrysalises. This also means that planting milkweed for monarch caterpillars in California won't help the butterflies that we see here, although it would help butterflies that are destined to overwinter elsewhere. What will help local butterflies--monarchs and otherwise, and all nectar-feeding insects, in fact--is planting California native plants, to provide them with the nutrition they have evolved to survive on.
People call them air rats or trash birds, but I really like gulls. Especially the western gull (Larus occidentalis), known colloquially among birders as the WEGU. Yes, gulls eat garbage, but that's only because humans are so good at making garbage and leaving it all over the place. Other gulls may travel quite far inland--in fact, the state bird of Utah is the California gull (Larus californicus)--but the WEGU is a California Current endemic species. This means that its natural food sources are the fishes and invertebrates of the California Current, which flows southwards along the west coast of North America. As a result, it lives in only a very narrow strip of coastline, nesting on cliffs and restaurant roofs.
Case in point. Yesterday afternoon I was at Moss Landing with my marine biology students. We had hiked along the road, over the dune to the beach, down the beach a ways, and returned over the dune to circle back to our starting point. The last item of note that we all watched was a western gull hunting along the shoreline of the Moss Landing harbor.
It had grabbed a crab. It looked like a rock crab, but I couldn't tell what species.
The crab wasn't dead, and was thrashing around enough to make it difficult for the gull to get a good grip on it.
The crab gets a reprieve!
But the gull didn't give up. It reached down, came back with the crab in its beak, and then flew off.
I don't remember what I expected from my first view of Death Valley. I knew it to contain the lowest elevation (Badwater Basin, 282 feet below sea level) in North America and that it was really hot in the summer, but beyond that I had no clue. [Aside: the marine biologist in me wondered which metric 'sea level' refers to, and decided that it was probably mean low low water] I certainly wasn't prepared for the spectacular geology, although in retrospect I shouldn't have been so surprised. We didn't see much in the way of wildflowers, for one reason that I didn't anticipate but which makes perfect sense: although Death Valley received enough winter rain to form a temporary lake in the valley, there hadn't been enough rain in the autumn to trigger a superbloom. That was fine by me, as I'd already seen many wildflowers on the trip and was happy to be fascinated by the geology.
There are at least two small waterways in Death Valley National Park that are called Salt Creek. The first one we encountered was in the hills above the valley, and is a rare desert riparian area.
This Salt Creek is fed by several small natural springs and runoff from the scant winter rains. As you can imagine, this oasis is a vital necessity for wildlife. Animals as large as desert bighorn sheep and as small as quail depend on this water source, which may contain the only somewhat reliable drinking water for 15 square miles.
As I mentioned, for me, Death Valley ended up being all about geology. I knew the valley floor was where we would find the lowest elevation in North America: Badwater Basin, 282 feet (86 m) below sea level. And now I can say that I've seen it, but there isn't much to see except the line of other tourists hiking out across the salt flats to take photos of the sign. So as a must-see destination, Badwater was interesting but not compelling. We skipped it.
But the rocks! The hills surrounding the valley, especially those on the eastern side, are spectacular. My favorite area was a range of hills called Artists Palette, viewable from a gorgeous 1-way loop drive off of Highway 190. When I saw the name on the map I thought it must be a place either a location where painters found minerals they could use to make paint, or a scene they liked to paint. Fortunately we decided to take the detour that meanders through the formations, so we could get off the main road and just gawk. I had never seen anything like this scenery. I know enough geology to understand that minerals come in all sorts of colors, but had not seen them together like this in a natural state. My eye is always drawn to colors, and I couldn't stop goggling at the variety of umbers, ochres, greens, and pinks, all jumbled together like some giant's ice cream sundae.
It's impossible to capture the grandeur of this landscape in a photograph. You really have to see Artists Palette in person to appreciate the vibrant colors of these hills. If you ever go to Death Valley , take the time to drive this little loop. You won't regret it!
Across the valley to the west, are the Panamint mountains. Beyond them, the Owens Valley and the mighty Sierra Nevada!
So those are the rocks. The fish were in the second Salt Creek that we encountered, about 20 miles north of the Artists Drive loop. This Salt Creek is one of the remnant small bodies of water left after Lake Manly dries up. Lake Manly is a temporary lake that occasionally forms in Badwater Basin after unusual heavy rains. Most of the time, though, Badwater Basin is dry except for some small creeks. Salt Creek generally flows from north to south down the valley and eventually disappears into the sand.
Salt Creek is inhabited by a little pupfish, Cyprinidon salinus salinus, that looks like and is about the size of a guppy. Well, maybe it's a little bigger than a guppy. Populations of pupfish inhabit several creeks scattered over the desert across California and Nevada. Over time they have evolved into 10 genetically distinct species and subspecies, each adapted to the nuances of its particular stream. Two of the 10 have gone extinct in historic times. The Salt Creek pupfish, C. salinus salinus, is endangered, due to the ephemeral nature and fragility of its environment.
They are called 'pupfish' because they appear to be playing like puppies. Plus, they are very cute. But life as a fish in one of the driest places on the planet is a tough gig. Pupfish live short, intense lives, growing to adulthood and breeding in the span of a single year.
Salt Creek pupfish (Cyprinidon salinus salinus) in Death Valley
As you can see, the creek is hardly deep enough for these little fish to swim. Pupfish exhibit the sexual dimorphism common in fishes--females are rather drab and nondescript, while males are more colorful. The behavior that was described as playful, earning the fish the moniker 'pupfish', is really all about the business of living. Males are territorial, defending a spot against other males. When a female chooses to spawn with a male, she enters his territory. Then the two of them perform a short, wiggling dance, and spawn together.
From the perspective of an evolutionary biologist, the isolated pupfish populations are fascinating. Each waterway inhabited by pupfish is an independent 'island' in a very real sense of the word. The fish cannot migrate between streams, and thus populations evolve independently of each other. This is called allopatric speciation, from the Greek roots 'allo-' meaning 'other' and '-patry' meaning 'country'. Over time, each population becomes reproductively isolated from the others, so that even if Manly Lake were to become once again a permanent body of water, the fish from different streams would be unable to mate with each other.
Of all the things that manage to eke out a living in what is arguably one of the most inhospitable places in the world, these little fish are my favorite. Major props to them, for surviving where they do and making it look like fun!
Joshua Tree National Park gained a certain notoriety this past winter, when idiots went there during the federal government shutdown and trashed the place. The vandals chopped down the iconic Joshua trees (Yucca brevifolia), let their dogs run around unleashed, left litter scattered over the landscape, and carved new roads through the desert. I'd like to give most people the benefit of the doubt and assume that they didn't realize the damage they were doing to the park. However, it takes only a few bad apples to destroy a public resource for everybody, as we've all experienced at some point.
The very first thing I learned about Joshua Tree is that it has two distinct desert habitats. Hey, I'm a marine biologist, and the desert--any desert--is new territory for me. None of this landscape has been anywhere near the ocean for millions of years! Anyway, the eastern half of the park is Colorado Desert, which is similar to what we had seen at Anza-Borrego State Park. Many of the plants in this region were also familiar to us because we had seen them in Anza-Borrego, but for the most part were more abundant here in Joshua Tree.
For example, we saw many more bluebells (Phacelia campanularia) at Joshua Tree than in Anza-Borrego. The P. campanularia at Joshua Tree also looked healthier (more robust and vigorous, less spindly) than they did in Anza-Borrego. Perhaps the higher elevation of the Colorado Desert in Joshua Tree (approximately 914 meters, or 3000 feet) compared to Anza-Borrego (182 meters, or 597 feet) accounts for this observation.
I really liked the Colorado Desert in Joshua Tree. Even though it was the same ecosystem as what we saw in Anza-Borrego, here the flowers seemed more colorful and striking. The yellows were a little brighter, and the pinks and blues a little deeper. The scenery was breathtaking everywhere I looked. I wish my photos could do justice to the beauty of the landscape.
Aside from the desert bluebells, other flowers that we had seen at Anza-Borrego included the brittlebush (Encelia farinosa), which seems to be ubiquitous in the Colorado Desert. The Arizona lupine (Lupinus arizonicus) was also common in Joshua Tree; like the bluebells, these appeared to be more robust here than in Anza-Borrego.
There were new flowers, too. My favorite, which I didn't see a lot of, was this desert globemallow, Sphaeralcea ambigua:
Here's a close-up of the same plant. Look at that gorgeous orange color!
Against the prevailing palette of yellows and purples, this orange really stood out and caught the eye. This plant is also called the apricot mallow, for obvious reasons.
Some other flowers that we saw:
Among all the colorful flowers in the overall landscape, there was this very subtle plant, easily overlooked by eyes accustomed to more brilliant blossoms.
Something that tickled my funny bone was the little chia plant, Salvia columbariae. It looks like a prickly purple pom-pom. Two days in the desert had taught me not to touch things if I didn't know what they were, but I had to know if these blossoms were as pokey as they looked. They weren't!
There are parasitic plants in the desert, too. The red branches in this bush are the desert mistletoe (Phoradendron californicum), a hemiparasite. It drains water and nutrients from its host plant but performs its own photosynthesis.
In Joshua Tree National Park there's an area called the Cholla Cactus Garden. Chollas are cactuses with cylindrical stems, rather than the flat stems of the beavertail or prickly pear cactuses. The most common one in the Colorado Desert (that we saw, at least) was the teddybear cholla, Cylindropuntia bigelovii. As the name implies, it's a cute, fluffy cactus, but it's definitely still a cactus.
The teddybear cactus blooms in May and June, so we didn't see any flowers. In addition to having the normal plant sex using flowers, these cactuses also reproduce clonally by dropping branches. The dropped pieces roll around and find a new place to attach and grow. Interestingly, this type of clonal replication, called budding, is common in many marine invertebrates!
Here's a newly detached bud from a teddybear cholla:
And here's a recently established, young plant:
Cute little cactus, isn't it?
The trees that give Joshua Tree National Park its name live in the higher and cooler western region of the park, known as the Mojave Desert. The Joshua trees (Yucca brevifolia) live singly or in clusters. In some ways, Y. brevifolia is the symbol of the Mojave Desert. They are also abundant in the higher elevations of the Tehachapi Mountains along Highway 58 between Bakersfield and the town of Mojave.
In Joshua Tree National Park, said trees were blooming in late March.
I'll have more to say about reproduction in Joshua trees and some other desert plants in another post. This one is getting long, and we had more desert adventures to come.
The first new-to-me visit on our spring break road trip was Anza-Borrego State Park in the southern California desert. We arrived late in the day on Monday and had just a brief chance to look around. On Tuesday we got up early and went for a hike, trying to avoid some of the midday heat. Fortunately there was a bit of a breeze, which helped with the heat but made flower picture-taking challenging.
Anza-Borrego is located in the Colorado Desert, which is a western subdivision of the Sonoran Desert. The Colorado is a low-altitude desert (most of the surrounding hills are only ~900 meters tall) and thus gets much hotter in the summer than deserts at higher elevations, and very rarely experiences a winter frost. Winter is the main rainy season and some regions also receive rain during a late-summer monsoon season.
After a rainy winter, the desert explodes into vibrant life:
The color of the day at Anza-Borrego was yellow. More details on the yellow players in a bit.
It had rained a few days prior to our visit, and there a stream was flowing through the desert.
This running water would be a temporary situation, of course, but one that is of great help to the wildlife in the park. At the park visitor center I read that wildlife large and small come to drink from the shallow streams, and that if we were to see bighorn sheep approaching the water we should stay out of their way. Water is so scarce for these animals that any delay in getting to it, or any separation of individuals from their family unit could be very stressful. I didn't know whether or not we'd even see the sheep, since they are shy, but we got lucky!
Handsome fellow, isn't he? He was eating and didn't seem to mind us hikers as long as we stayed on the trail. Of course, there was an idiot who approached too close to get a better photo, and this ram wasn't happy about it. He withdrew away from us and then went about his business. Other sheep wandered through, too, to forage or drink from the stream. But this big guy gave me the best photo op.
A visit to the desert this spring, after all the rain we had over the winter, was all about the wildflowers. Most of them were new to me. One thing that struck me was that, instead of the carpets of color that we'd seen at Carrizo Plain or Antelope Valley, flowers at Anzo-Borrega were much more widely dispersed. Some species were very common and others I didn't see more than once or twice.
As I mentioned above, yellow was the predominant color at Anza-Borrego. There were several daisy-like flowers in both yellow and white, and some were very common. Fortunately for me, the visitor center had an easy-to-use pictorial guide of the most common wildflowers; using that, some wildflower field guides that we brought with us, and Calflora.org, I may have identified them all correctly. I'm sure that somebody will point out any identifications that I got wrong.
One of the defining characteristics of E. farinosa is the way that the blossoms are raised up above the grayish-green foliage. It's a cool morphology, and makes the plant look very different when you see it from the side. Here's a shot that shows it:
And brittlebush was very abundant!
Another very abundant yellow flower was the very aptly named desert dandelion, Malacothrix glabrata. It looks like a typical dandelion, perhaps a more pale buttery color than usual, and when mature the blossoms have a small purplish red spot in the center.
Our state flower, Eschscholzia californica, is typically a brilliant pure orange color, although sometimes the color can be more yellow. In Anza-Borrego I saw some plants whose foliage looked poppy-ish, but the blossoms didn't look quite right--a little too small to be California poppies and a color that was definitely yellow rather than orange. Turns out, though, that they were gold poppies (E. parishii)!
And who can resist a plant called ghostflower? That palest of yellows, almost but not quite white, combined with the tiny dark speckles, makes the plant seem very quiet--indeed, almost spooky. Ghostflower is easily overlooked, compared to the vibrant yellows of brittlebush, poppies, and dandelions.
One of my favorite flower color combinations is yellow, white, and purple. Imagine how pleased I was to find it in the desert!
The color purple was represented by two species of Phacelia, P. distans and P. campanularia. Phacelia distans was by far the most common in the floors of the valleys, and we saw P. campanularia at higher elevations.
This is Phacelia distans. Note the shape of the inflorescences, and how the blossoms are arranged.
And this is Phacelia campanularia, the desert bluebell:
These plants have the same blossom shape, but very different blossom arrangements and foliage morphology. Nifty, the differences between presumably closely related species, eh?
Another flower in the purple family was the desert sand verbena (Abronia villosa). It occurred in sandy soils, often in washes or dunes, similar to the sand verbena that I see on beaches along the coast.
The pink color family was represented by the bright pink Bigelow's monkeyflower, Diplacus bigelovii. They were fun. The golden-orange throat is the diagnostic feature for this species.
I didn't get very many good pictures of the white flowers. It always seemed to be especially windy when we saw them. Desert chicory (Rafinesquia neomexicana) is a white daisy-like flower.
This being the desert, much of the plant biomass was succulent in nature. The ocotillo were blooming, as were the teddybear cholla and other cactuses.
Everything living in the desert survives only if it can take advantage of the minimal precipitation that falls every year. Cactuses must suck up as much water as they can during the wet season, and store it for use during the hot, dry summer. Barrel cactus (Ferocactus acanthodes) this spring are fat, like the barrels for which they are named, and full of water. Their bodies are pleated longitudinally, allowing them to swell up when water is available. Then, as their water stores are depleted during the summer, the pleats fold together and the body becomes more compact. The large saguaro cactuses in the Sonoran Desert do the same thing.
A cactus whose blossom definitely belongs in the pink category is the beavertail cactus (Opuntia basilaria). I think it was early in the blooming season for them, as I never saw any plants with more than a few open flowers, but most of them had many buds developing.
The chollas are cactuses in the genus Cylindropuntia, characterized by cylindrical stems. The teddybear cholla (C. bigelovii) was the one we saw at Anza-Borrego. It has dense spines that give it a fuzzy look but in reality form an impenetrable defense--it manages to say "I'm cute and fuzzy!" and "Don't touch me!" at the same time.
The teddybear chollas were very abundant at Anza-Borrego. We continued to see them as we continued on our trip. Next stop, Joshua Tree!