For a long time now I've wanted to document a phenomenon that I've observed many times: the way that some birds change color when they move from the light into the dark. I'm sure you've noticed this before, in the vibrance of a peacock's tail that turns to black when the bird moves into the shade. But have you ever thought about why some feathers change color with changing light, while others don't?
It turns out that there is more than one explanation for feather color. Some feathers are colored because of the pigments they contain. Pigments are molecules that absorb some wavelengths of light and reflect others; the wavelengths that are reflected are detected by our eyes and interpreted by our brain as color. There are three groups of pigments that occur in feathers, each of which contributes certain colors to a bird's plumage: (1) melanins--responsible for pale yellows, dark browns, and blacks; (2) porphyrins--producing reds, pinks, browns, and greens; (3) carotenoids--contributing bright yellows and oranges. Pigments can work in concert, too, as when melanins and carotenoids combine to produce olive-green.
Pigment molecules are independent from the underlying structure of a feather. It turns out that the structure itself can produce color. For example, the blue in the feathers of Steller's jays (Cyanocitta stelleri) is due to scattering of light by tiny air pockets in the feathers. When sunlight strikes the filament of a feather, the blue wavelengths are refracted back into the atmosphere where they can be picked up by our retinas, and the other wavelengths are absorbed by a layer of melanin at the base of the filament (which is why we don't see them).
A second kind of structural color is iridescence. This is due to the microscopic structure of the feather's barbules. These barbules act like prisms, refracting light as it hits the feather. The appearance of the light (brighter or darker) changes as the angle of viewing changes.
My favorite example of iridescence in birds is in the hummingbirds. These ornithological gems flit about so rapidly that it can be hard to get a good look at them, but their brilliant colors are stunning. This afternoon I was finally able to take a series of photographs that show how minute changes in a hummer's posture can change its coloration. This male Anna's hummingbird (Calypte anna) posed very nicely and allowed me to snap off a series of photos. In this series of photos I have edited them only to crop them to the same size and center the bird in each one. I have made no adjustments to color or saturation.
And to drive home just how brilliant that pink head is, here's a shot of the same bird, this time on the opposite side of the feeder.
Anybody who says pink isn't a masculine color has obviously never seen a male Anna's hummingbird in full sun!
It seems that most years, the Memorial Day weekend brings some of the lowest spring tides of the year, and 2017 certainly fits the bill. I've been out for the past two days, heading out just as the sun is starting to rise, and already I've seen enough to whet my appetite for more. And with plans for the next few days, I'm pleased to say that my dance card is completely full for this tide series. There are a lot of stories building out there!
At this time of year everything is growing and reproducing. Many of the larvae I've seen in the plankton have parents that live in the intertidal; makes sense that those parents should be having sex now. Barnacles, for example, copulate when the tide is high. I've seen them go at it in the lab, but never in the field, as they don't mate while emersed. This morning I interrupted a pair of isopods locked in a mating embrace, and they swam off, still coupled together, when I disturbed them. Other animals were much less shy. Lifting up a curtain of Mazzaella to see what was underneath, I spotted a small group of dogwhelks (small, predatory snails). I can't be certain, but suspect they were having an orgy.
A short distance away I found the inevitable result of the dogwhelk orgies.
Each of those urn-shaped objects is an egg capsule, containing a few dozen developing embryos. After the snails copulate the mating individuals go their separate ways. The females lay these egg capsules in patches in the mid-intertidal, usually on a vertical surface under the cover of algae to minimize the risk of desiccation.
For many years now, some of my favorite animals have been hydroids. I worked in a hydroid lab as an undergraduate, and this is when I fell in love with the magic of a good dissecting microscope. A whole new world became visible, and I found it easier than I ever imagined to fall under the spell of critters so small they can't be seen with the naked eye. I still do.
Hydroid colonies come in a variety of forms, shapes, and colors. Most of them are small and cryptic, resembling plants more than any 'typical' animal, and aren't easily seen unless you're looking for them. One intertidal species, however, is pretty conspicuous even to the casual tidepool visitor or beachcomber. It often gets torn off its mooring and washes up on the beach.
A hydroid colony is the benthic polyp stage of the standard cnidarian life cycle. The polyp represents the clonal phase of the life cycle and reproduces by dividing to make several copies of itself. In a colony such as a hydroid, the polyps remain connected to each other and even share a common digestive system. The polyps don't reproduce sexually. That function is reserved for the medusa stage of the life cycle. Some hydroid colonies produce free-swimming medusae, and others hang onto reduced medusa buds or structures so un-medusa-like that they're called gonangia. Aglaophenia is a hydroid that houses its sexual structures in gonangia that are located on the side-branches of the fronds.
Here's a closer view of a single frond of the Aglaophenia colony. I had to bring it back to the lab to look at it under the scope.
The gonangia look like leaves, or pages of a book, don't they? After working a low tide I'm always hungry, and when the lows are early in the morning I'm often cold and sleep-deprived as well. That's my excuse for not dissecting open one of the gonangia to see what's inside.
Even the algae are getting into the act of reproducing and recruiting. This spring I've noticed a lot of baby bullwhip kelps (Nereocystis luetkeana). Nereocystis is one of the canopy-forming kelps in subtidal kelp forests along our coast, but every year some recruit to the low intertidal. However I don't remember seeing so many baby Nereocystis thalli in the tidepools. The smallest one I saw this morning had a pneumatocyst (float) the size of a pea! In mature thalli, the float might get as big as a cantaloupe.
Nereocystis doesn't usually persist or get very large in the intertidal. It is more common to see detached thalli washed up on the beach than to see a living bullwhip kelp longer than about 2 meters in the intertidal. Whether or not this particular nursery area results in an established population remains to be seen. I'm betting 'No' but could very well be proved wrong. Only time will tell.
Day 2 (24 March 2017): Tehachapi, Antelope Valley, and Wind Wolves
We spent the night in Bakersfield and the next morning (24 March 2017) headed up over Tehachapi Pass and headed into Antelope Valley.
It had been many years since I'd driven over Tehachapi Pass, and I didn't remember ever having seen Joshua trees before. Maybe I was always sleeping on that part of the trip. Once we got past the windmills at the top of the pass--most definitely Not Good for my concussed brain--and started descending into the valley there were Joshua trees all over the place! So cool! And with this year being the 30th anniversary of U2's best (in my opinion) album, how appropriate.
To my admittedly inexperienced eye, Joshua trees are the symbols of the Mojave Desert, as the saguaro is the symbol of the Sonoran Desert. None of the Joshua trees that we saw at Tehachapi were blooming, although I heard from a friend that they were in bloom slightly farther south at Lancaster.
Continuing on, we drove through the desert scrubbiness and eventually could see orange splashed onto the distant hills. We stopped to pick up sandwiches at a corner market and then headed towards the Antelope Valley Poppy Reserve. And bang! all of a sudden we were in the poppy fields.
California's state flower grows as either a perennial or an annual, depending on how much water it receives. In desert areas in the south it behaves like an annual, whereas in moister areas along the coast and in gardens it can come back as a perennial. There are several subspecies of E. californica, each adapted to a particular habitat within the state. Blossom color varies from a golden yellow (very similar to that of fiddlenecks, actually) to a deep intense orange.
Our intent was to stop at the visitor center of the park and pick up a trail map, but we never got there. We arrived at early mid-day on a Friday, when everybody from Los Angeles showed up, and the line of cars trying to get into the park was backed up almost to the road. Um, no thanks. Besides, we saw all these poppies from the road, and could find places sort of off the beaten track with fewer people tromping around with selfie sticks than would be inside the actual park. Now I'm not one to discourage people from visiting our state parks, but if you decide to go here, try to arrive earlier in the morning on a midweek day. And time your visit for a sunny day, when the poppies will be open.
And looking up towards the hills we saw pastel paintings. The orange flowers are poppies, I'm guessing that the yellow is goldfields, and the purple is lupines.
And in terms of lupines, Antelope Valley was the best place we visited. When we made plans to come here I had grandiose ideas of capturing that perfect iconic photograph of purple lupines and orange poppies together. You know the one. Unfortunately I think we arrive a week or two early to catch the peak of the lupine bloom. I never did see nice full lush poppies and blooming lupines in the same spot.
We did, however, see several nice lupine bushes in the various washes around the poppy reserve. Honeybees were glad to see them, too.
As glorious as the poppies were, we needed to keep moving in order to meet up with friends on the coast. Working our way westward we stopped at the Wind Wolves Preserve, an ecological reserve managed by the Wildlands Conservancy. I had never heard of the place and wasn't sure what to expect. What I got was a lovely surprise.
There are, of course, no wolves in this part of California. So then, why the name? According to a sign at the head of the wildflower trail, the name refers to the Preserve's long grasses, which undulate like running animals when the wind blows through them. I wasn't carrying the tripod with me so I didn't try to take any video. However, on our way from Antelope Valley we stopped at Tejon Pass, where the wind was blowing pretty well. I took this video there.
It does look like one of those aerial views of a herd of galloping ungulates, doesn't it? Perhaps not wind wolves, exactly, but at the Preserve it was easy to imagine how the place got its name. The wildflower walk, a bit less than a mile long, winds through rolling hills covered with grasses and dotted here and there with flowers. There were several small groups of people hiking the trail, and it wasn't uncommon to have them disappear completely from the landscape when they got lost in the grasses as the trail dipped into a small depression.
No doubt the resemblance to running wolves will be stronger when the grasses are a bit taller.
We were perhaps two weeks ahead of the bloom and most of the flowers were just starting to open up. The overall effect was a cool wash of green dotted here and there with bright splashes of color. There were lupines, of a smaller ground-growing type rather than the bush lupines we had seen in Antelope Valley, and a plant that we had first seen a lot of on the Carrizo Plain, another whimsically named flower called purple owl's clover (Castilleja exserta). As its scientific name implies, owl's clover is a member of the paintbrush family of plants.
And this might well be my favorite photo of the entire trip:
We had already seen many familiar and not-so-familiar birds on the trip, and it was at Wind Wolves that I saw my first ever horned lark (Eremophila alpestris). This individual wasn't very shy at all; it let us approach within 2 meters on the trail before running off ahead to wait for us again. It had such expressive postures, and a curious look on its face. If there hadn't been a family with small kids behind us on the trail, I could have watched this bird for a long time. But we couldn't block the trail just because there was an interesting (to us) bird standing in it, so we let the family pass and the lark flew off into the grasses. They are social birds so no doubt it had friends and family of its own to join.
We saw lizards, too, most notably the western side-blotched lizard (Uta stansburiana ssp. elegans). These lizards have very interesting gender expression, depending on color morph: there are three male morphs (orange-throat, yellow-stripe, and blue-throat) and two female morphs (orange-throat and yellow-throat). Sounds crazy, doesn't it? The female morphs differ in egg-laying strategy. Orange-throat females lay many small eggs and defend territories, while yellow-throat females lay fewer larger eggs and are less territorial.
Work by Barry Sinervo's group at UC Santa Cruz showed that the three male color morphs also have different reproductive strategies. They are locked in an evolutionary game of rock-paper-scissors: each color can dominate one (but not both) of the other colors. Note that in this context 'dominate' doesn't necessarily mean that one lizard beats up the other, but rather has greater reproductive success than the other. Orange-throats are the most typically testosterone-driven males; they are more aggressive towards other males and control territories containing several females. Yellow-stripe "sneaker" males hang around the edges of an orange-throated male's territory and sneak copulations with females while the territory holder's attention is elsewhere. Blue-throats have an intermediate level of aggression; they can defend a single female from other blue-throats and yellow-stripes, but not against an orange-throat. In a nutshell:
Last week I went up to Davenport to do some collecting in the intertidal. The tide was low enough to allow access to a particular area with two pools where I have had luck in the past finding hydroids and other cool stuff. These pools are great because they are shallow and surrounded by flat-ish rocks, so I can lie down on my stomach and really get close to where the action is. At this time of year the algae and surfgrasses are starting to regrow; the surface of the pools was covered by leaves of Phyllospadix torreyi, the narrow-leafed surfgrass.
Parting the curtain of Phyllospadix leaves to gaze into the first pool I was pleasantly surprised to find this. What does it look like to you?
There are actually two very different organisms acting as main subjects in this photo. The pink stuff is a coralline alga, a type of red alga that secretes CaCO3 in its cell walls. Coralline algae come in two different forms: one is a crust that grows over surfaces and the other, like this, grows upright and branching. Because they sequester CaCO3, corallines are likely to be affected by the projected increase of the ocean's acidity due to the continued burning of fossil fuels. Ocean acidification is one of the sexy issues in science these days, and although it is very interesting and pertinent to today's world it is not the topic for this post. Suffice it to say that changes in ocean chemistry are making it more difficult for any organisms to precipitate CaCO3 out of seawater to build things like shells or calcified cell walls.
It's the tannish featherlike stuff in the photo that I was particularly interested in. At first glance the tan thing looks like a clump of a very fine, fernlike plant. It is, however, an animal. To be more specific, it is a type of colonial cnidarian called a hydroid. I love hydroids for their hidden beauty, not always visible to the naked eye, and the fact that at first glance they so closely resemble plants. In fact, many hydroid colonies grow in ways very similar to those of plants, which has often made me think that in some cases the differences between plants and animals aren't as great as you might assume. But that's a matter for a separate essay.
I collected this piece of hydroid and brought it back to the lab. The next day I took some photos. To give you an idea of how big the colony is, the finger bowl is about 12 cm in diameter and the longest of these fronds is about 3 cm long.
And here's a closer view through the dissecting scope.
Each of the fronds has a structure that we describe as pinnate, or featherlike--consisting of a central rachis with smaller branches on each side. This level of complexity can be seen with the naked eye. Zooming in under the scope brings into view more of the intricacy of this body plan:
At this level of magnification you can see the anatomical details that cause us to describe this animal's structure as modular. In this context the term 'modular' refers to a body that is constructed of potentially independent units. A colony like this is built of several different types of modules called zooids, some of which are familiarly referred to as polyps. Each zooid has a specific job and is specialized for that job; for example, gastrozooids are the feeders, while gonozooids take care of the sexual reproduction of the colony. In this colony of Aglaophenia each of these side branches consists of several stacked gastrozooids, which you can see as the very small polyps bearing typical cnidarian feeding tentacles. Aglaophenia is a thecate hydroid; this means that each gastrozooid sits inside a tiny cup, called a theca, into which it can withdraw for protection. Those larger structures with pinkish blobs inside are called gonangia. A gonangium is a modified gonozooid, found in only thecate hydroid colonies, that contains either medusa buds or other reproductive structures called gonophores.
Pretty complicated, isn't it? Who would expect such a small animal to have this much anatomical complexity?
In the second pool I found an entirely different type of hydroid. At first glance this one looks more animal-like than Aglaophenia does, although it is still a strange kind of animal. This is Sarsia, one of the athecate hydroids whose gastrozooids do not have a protective theca. It might be easier to think of these and other athecate hydroids (such as Ectopleura, which I wrote about here and here) as naked, with the polyps not having anywhere to hide.
Each of these polyps is about 1 cm tall. The mouth is located on the very end of the stalk. The tentacles, not quite conforming to the general rule of cnidarian polyp morphology, do not form a ring around the mouth. Instead, they are scattered over the end of the stalk.
Here's a closer view:
In the hydroid version of Sarsia, the reproductive gonozooids are reduced to small buds that contain medusae. You can see a few round pink blobs in the lower right of the colony above; those are the medusa buds. The medusae are fairly common in the local plankton, indicating that the hydroid stage is likewise abundant. Here's a picture of a Sarsia medusa that I found in a plankton tow in May 2015.
The medusa of Sarsia is about 1 mm in diameter and has four tentacles, which usually get retracted when the animal is dragged into a plankton net. Sometimes, if the medusa isn't too beat up, it will relax and start swimming. I recorded some swimming behavior in a little medusa that I put into a small drop of water on a depression slide. It refused to let its tentacles down but you might be able to distinguish four tentacle bulbs.
There's a lot more that I could say about hydroids and other cnidarians. They really are among the most intriguing animals I've had the pleasure to observe, both in the field and in the lab. I've always been fascinated by their biphasic life cycle, with its implications for the animals' evolutionary past and ecological present. Perhaps I'll write about that some time, too.
Last week I finished my 30-day personal photography challenge, and I'm finally getting around to putting up a follow-up to this post. These are the photos from the second half of the challenge.
Day 16: Egret on the stack at Younger Lagoon. A high surf warning is in effect through today and the waves are BIG! This rock stack sits at the mouth of Younger Lagoon and gets bashed by waves 24/7/365. Usually on days like today I'll see pelicans and cormorants, true seabirds, hanging out on the stack and getting blasted by salt spray. Today a pair of snowy egrets (Egretta thula) landed on the stack but didn't stick around for more than a few seconds. As birds of wetlands and marshes, they didn't like it out there in these conditions.
Day 17: Sunrise. I know, another sunrise. But this time, instead of the panoramic scale of brilliant colors I wanted to zoom in and capture the chiaroscuro effect of the backlit trees.
Day 18: This day showcased one of my favourite marine artefacts. This is the test, or internal skeleton, of the red sea urchin Mesocentrotus (formerly Strongylocentrotus) franciscanus. I took this photo with the 35mm lens.
Day 19: Pie makings. This is the first since I started this project that I've not been really happy with any of my photos. Maybe that's because I took a lot of shots of dead stuff at the marine lab this morning. However, this one does have a certain amount of visual interest, I think. As usual, the colors are spot on.
Day 20: Jade plant. Day 20 had me playing with depth of field again. I wanted to photograph something green, to remind myself of the resiliency of life. We somehow acquired this jade plant several years ago, and have dragged it with us from house to house. I think it has made three moves with us. I pretty much ignore it, and it had mostly died before last year's El Niño rains brought it back to life. And now it looks lush and green again! And may I just keep singing the praises of this 35mm lens? I feel it is making me a much better photographer.
Day 21: Diving grebe. A friend invited me to join her at the harbor for some "therapeutic docking". It took me about 10 minutes to remember that my concussed brain hurts when I lie with my head hanging over the edge of the dock. Oops. So I took pictures above water while my friend hunted for slugs. I really like this particular action shot of a grebe taking a dive from the surface. Bloop!
Day 22: Not a sunrise! Looks like another sunrise, doesn't it? But I took this yesterday at 17:00 so it isn't a sunrise even though the view is almost due east. So what is going on here?
Day 23: Super moon! I took on the super moon to practice some low light photography. I can see why photographers like those big telephoto lenses! My 18-140mm lens did a good job with details of the moon's surface, which was nice to see. Had to do some digital zooming to get this view.
Day 24: Lavender flower. This day saw me experimenting with bokeh. Before I started playing with this camera I didn't really appreciate the aesthetic potential of the non-subject material in a photograph. This study has really changed the way I look at the world. I feel that my artist's eye has developed quite a lot.
Day 25: Setting moon. Last night we were fogged in at sea level so we went uphill to get above the marine layer. From that experiment it's clear that I need more practice with night photography and long exposures. None of the pictures I took last night was very good in terms of technique, but one of them is aesthetically interesting and I may share it later. Anyway. This one is the super moon setting behind the trees this morning, at about the same time the sun was rising behind me.
Day 26: Gull in flight. I'm learning that photography is about the moment as much as the subject matter. In this case the subject is a western gull, a California Current endemic species, in flight. What do you think of the moment?
Day 27: Light through stained glass window. I went down to the church this afternoon to take pictures of the stained glass windows while the organ was getting fixed, then broken, then fixed again. I like the way the late afternoon sun shone through one of the south-facing windows and onto the opposite wall. I find the effect to be kind of spooky and not at all like the pictures I usually take. Maybe I need to play around more with angles as composition. The church dates back to 1864 (old by California standards!) and is the oldest church building still in use in Santa Cruz County. The gas lights, one fixture of which can be seen in the right-hand side of the photo, are part of the original architecture. The hanging electric lamp is not. We still use the gas lamps for evening services, and they are quite lovely when lit.
Day 28: San Juan Bautista. We went to San Bautista to meet family and friends for a birthday lunch and spent some time wandering around the mission grounds. This image captures the three elements of every California mission--the Indian supplicant, the cross, and the bell tower--and hints of the tension in these settlements. Like it or not, the missions are an important part of California history despite their record of enslavement of the people who lived here first.
Day 29: Chomp! This day was once again all about the moment. Lucie (calico) and Maggie (tortie) were napping together on the couch when Lucie woke up and started grooming Maggie. Usually it goes the other way around. This time Maggie put up with it for a long time before giving Lucie one warning chomp. After this they groomed each other for a while and then continued their nap for another couple of hours.
Day 30: Tiny mushrooms. I wanted the last entry to be something special so I waited until we went hiking at Big Basin Redwoods State Park for Green Friday. Hiking through the redwood forest we saw beauty all around us. And mushrooms everywhere! I was messing around with bokeh again and love how these little mushrooms look against the blurred background. My challenge is finished and I've learned a lot about my camera and taking pictures. Mission accomplished!
I feel that I've learned a lot during this challenge, both about my new camera and about photography in general. And I've developed a whole new appreciation for composition and especially for bokeh. I've completed the challenge, but intend to keep taking pictures as frequently as I can. I still have so much to learn!