October 6, 2008

BLACK-VULTURE CENOTE
A water-filled sinkhole, or cenote, near my casita is a roosting spot for Black Vultures. They overnight there, spend mornings in dead tree snags preening and basking in the sunlight, in the afternoons circle in convection currents above us, then as the sun sets they return to the cenote. The cenote provides a sheltered, humid, lush habitat very different from the surrounding arid, cattle-stomped, hacked-for-firewood scrub, so Tuesday morning I went there looking for special plants and animals. But before entering I had to sit awhile to admire those Black Vultures.

I arrived before convection currents begin forming and soon it was clear that the vultures abhorred the idea of taking to the air so early. Getting airborne seemed to be a dreaded chore for them so, if you approach them halfway non-threateningly, you can get fairly close. I drew near them like a lumbering cow, then sat and waited for them to get used to me. Their sounds fascinated me. Vultures are usually described as mostly silent, limiting their vocalizations to grunts and hisses, but the sound that got my attention was one like the woof! of a small, Schnauzer-type dog who can't make up his mind whether he needs to bark or not, so he barks halfheartedly as he looks away.

Later that day as I hiked through the scrub suddenly a loud, wind-ripping, whooshing noise tore through the space above me. At first I thought it was a low-flying jet with his engines off, but then I saw two Black Vultures displaying high in the sky. One vulture would dive at the other from high up, then pull up near the other so sharply that the whooshing sound was tremendous. You can see how this display would serve its purpose during courtship: The stronger the bird, the faster he's able to dive, the sharper he can make his pull-up, and the louder the resulting whoosh. The louder the whoosh, then, the healthier and stronger the prospective mate.

At https://www.backyardnature.net/n/08/081006bv.jpg you can see a Black Vulture at the cenote basking with his wings held against the sunlight. Tuesday morning sunlight was intermittent, so for long periods all the twenty or so vultures perched preening or just resting, but the moment sunlight broke through, in unison, they'd all unfurl their wings like the one in the photo, and keep them open until the next cloud covered the sun.

Perches were important to those vultures, and birds at the top of the pecking order got the best perches. If Alpha Vulture wanted a perch occupied by a lower-ranked bird he'd simply fly to the lower-ranked bird's perch. If the lower-ranked bird didn't get out of the way automatically, a few pecks would be exchanged, but then the lower-ranked bird would quickly abandon his perch anyway.

The above photo shows the whiteness typical of a Black Vulture's major wing feathers. Howell in A Guide to The Birds of Mexico and Northern Central America describes the Black Vulture's plumage as "black overall, white shafts above and webs below of outer 6 primaries form contrasting whitish wing panels." You can see yourself whether the white is limited to the outer six primaries. When Black Vultures are soaring overhead, their white wing-spots, or "panels," are easily discerned.

In the photo you can also see the vulture's long, stout legs. When I started birding back in the 60s, field guides always placed vulture illustrations among those of hawks and falcons, because vultures were regarded as most closely related to them. Now our New World Vultures are accepted as most closely related to storks, not raptors or even Old World Vultures. Those long legs make their stork affinities easy to believe.

By the way, you can see the difference in silhouettes between an overhead Turkey Vulture and a Black Vulture at https://www.backyardnature.net/n/08/081006bt.jpg.

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ANONA-EATING WOODPECKER
The anona tree outside my casita door still is bearing sweet fruit, and the neighborhood Golden-fronted Woodpecker, CENTURUS AURIFRONS, has been taking more than his share. You can see him pecking a fruit at https://www.backyardnature.net/n/08/081006gf.jpg.

This isn't the first time a Golden-fronted Woodpecker has revealed his sweet-tooth to me. During my winter, 2005 stay at San Juan Hacienda a bit north of here this bird pecked holes in immature coconuts and caused much damage in orange orchards.

Birders in the eastern US might see little difference between our Golden-fronted Woodpecker and the Red- bellied Woodpecker so common up there. Golden-fronted Woodpeckers, distributed from the southwestern US to El Salvador and Honduras, exhibit various geographical variations in Mexico. Our Yucatan subspecies dubius is distinguished from other subspecies by the very narrow barring on its back and its reddish belly at certain times of the year, the other subspecies sometimes showing yellow bellies. If you compare the above picture with the US's Red-bellied you'll see that the back of ours is darker overall because the black bars across the back are much narrower, more numerous and closer together.

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THE TROPICAL MOCKINGBIRD'S MISSING WING-PATCHES
Several times I've mentioned that our Tropical Mockingbirds look and behave almost exactly like those in the North, except that ours lacks the North's large, white wing-patches. This week I got a picture of one so you can compare its wing markings with those of the Northern Mockingbird in your field guide or maybe outside your window. The picture resides at https://www.backyardnature.net/n/08/081006cz.jpg.

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MUD-DAUBER ON MY SHIRT
I keep all my clothing hanging on a rope strung across my room, for if I store things in a box or suitcase they'll soon mildew -- develop dark speckling and they'll stink. The other day I went down the line fluffing out things to keep them dry and was surprised to find stuck on a shirt what you can see at https://www.backyardnature.net/n/08/081006dd.jpg.

The shirt had been hanging next to a window and a mud-dauber wasp had entered many times with loads of mud and built a cylindrical, dried-mud nest on the shirt. Once a mud chamber was created, an egg was laid inside and then the chamber was provisioned with stung spiders or maybe caterpillars or other such critters, and finally the tube was sealed. At the lower left in the picture an inset shows the sealed hole.

I removed the nest and stuck it in a dry crack between two cinderblocks.

Last week we looked at paper wasps and their covered nest outside my door. If you look at my Wasp Page at https://www.backyardnature.net/wasps.htm you'll see that my paper wasps are probably members of the subfamily Vespinae of the family Vespidae, because that subfamily is the only one mentioned producing nests consisting of "papery cells surrounded by covering."

Similarly, my shirt-loving mud-dauber probably provisioned her nest with spiders, because in the list of families at the above link the main prey for most mud-nest-building wasps is spiders.

The wasp world is vast and complex. On my Wasp Page, that outline of the most common wasp families, their prey and nest types can help you organize your thoughts about them.

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CENOTE WATER-HYACINTHS
Most of the water surface-area in the abovementioned Black Vulture Cenote is covered with a mass of Water-Hyacinths, EICHHORNIA CRASSIPES, of the aquatic Pickerel-Weed Family, the Pontederiaceae. The plants form a tangle about knee deep atop the water so dense that you can't see the water below them -- nothing but a solid, green mass of leaves and stems. Sometimes Water-Hyacinths, native to tropical and subtropical America, obstruct navigation by choking rivers, streams and canals. One just wonders how the species ever got established in this isolated cenote surrounded on all sides by arid scrub.

At the edge of the floating thicket a few plants were widely spaced enough for you to see the Water-Hyacinth's graceful form and the inflated leaf-petioles enabling them to float atop water, as shown at https://www.backyardnature.net/n/08/081006wj.jpg.

A few of those outer plants also were flowering, as at https://www.backyardnature.net/n/08/081006wh.jpg.

The blossoms were pretty enough for a close-up, shown at https://www.backyardnature.net/n/08/081006wi.jpg.

Rosy-lilac Water-Hyacinth flowers always bear that blue spot on the upper perianth lobe, with a yellow center-spot. I use the word "perianth" because in this monocotyledonous family the calyx and corolla are merged. Instead of the flower having three sepals and three petals, it has six perianth lobes, technically referred to as tepals.

In the picture the stiff, pale items with hooked tips and issuing from the flowers' throats, and ending in dark, flattish items, are stamens. Especially in the flower at the left you can see a white, spherical thing curving up about midway the stamens' fuzzy filaments. The white globe is the female stigma held aloft by the curve-necked style, which leads down into the flower's tube to the ovary.

Each Water-Hyacinth blossom bears six male stamens, though we can make out only three with long, stiff, fuzzy filaments. That's because a feature of flowers in the genus Eichhornia is that the six stamens arise from the perianth tube at different spots, so that some don't extend from the corolla like the three we see. At the throat's opening you can see one or two anthers of lower stamens peeping out.

What a contrast these succulent, gaudy, elegant, cenote-bottom plants made with the tough, spiny scrub surrounding us above. Sometimes I go into cenotes and just sit, in order to not become too arid myself.

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MYSTERIOUS DORSTENIA
Back in the early 70s I served as the naturalist on archaeological tours in Guatemala's Petén region. We specialized in visiting Maya ruins accessible only by boat and mule train, for in those days few roads penetrated much of the Petén. The expedition leader was an archaeologist who tried to interpret certain glyphs found on stone stele always present around ruins. Someplace he got the idea that one especially strange glyph represented a plant that always grew on the ruins. You might hike through marshy "jungle" for days not seeing the plant, but the moment you arrived at a ruin, this plant would be growing all over the ruin's limestone-block pyramids, temples and stele.

My opinion was that if any plant would was eligible for inclusion in Maya iconography, it was this one. Not only because of its almost uncanny attraction for sacred Maya temples, but also because anyone familiar with how normal flowers are "supposed" to look -- calyx with five sepals, corolla with five petals, ovary surrounded by stamens, etc. -- this little plant broke all the rules. You can see what I mean at https://www.backyardnature.net/n/08/081006do.jpg.

That's a DORSTENIA CONTRAJERVA growing on a limestone wall at the bottom of Black Vulture Cenote. Surely the two green "flowers" are unlike anything you've ever seen.

When you realize that Dorstenia belongs to the Fig Family, the Moraceae, many of you will instantly understand what's going on with Dorstenia's "flowers." For, you'll remember that fig "fruits" are weird affairs in which the actual fig flowers are tiny things strewn across the INTERIOR SURFACE of the empty-centered, ovate fig. For a more detailed look at fig-fruit anatomy, check out my Multiple Fruit Page at https://www.backyardnature.net/frt_mult.htm.

Well, those green "flowers" in the Dorstenia picture are basically what you get if you split open a fig and press it flat so that all the tiny flowers previously on the fig's interior now occupy one side of the flat-pressed thing. Each of those star-like items that seem like they should be flowers is actually a platform with tiny flowers on one side, and green, vegetative receptacle on the other.

The platform's shape -- a star with the top arm bent forward -- is approximately what the glyph looked like the archeologist was interested in.

Nearly always such strange-looking plants are considered as medicinal or magical by local people, and Dorstenia certainly has that reputation. In fact, throughout most of its distribution in Mexico it's called Contrayerba, or "against-herb," suggesting that it'll work against many maladies. Also it's called Yerba Santa, or "Blessed Herb," a name applied to many particularly virtuous herbs. Martinez's Las Plantas Medicinales de Mexico reports it as providing traditional remedies for everything from toothaches to tumors to snakebite.

I'd never seen Dorstenia this far north. I thought it was far too arid here for it. However, the moist shelter at the bottom of Black Vulture Cenote does feel pretty much like the humid, sepulchral "jungle" that at least once mantled northern Guatemala.

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BOAT LILY
Another sinkhole-bottom denizen of Black Vulture Cenote was the familiar-looking Boat Lily shown at https://www.backyardnature.net/n/08/081006tr.jpg.

It's familiar-looking because it's often grown as an ornamental in gardens here and in greenhouses and as potted plants beyond the tropics. It's TRADESCANTIA SPATHACEA, a member of the Spiderwort Family, the Commelinaceae. Around here you find it only in cenotes and the most shaded, sheltered parts of the scrub.

Note the curious manner in which the thumbnail-size, white blossoms emerge from the leaf bases. A close-up of a flower showing something else special about it is at https://www.backyardnature.net/n/08/081006ts.jpg.

Can you see how the blossom arises from what looks like a green, folded-together leaf? That's a modified leaf referred to as a bract and it protects the flowers. The delicate blossom develops inside the folded bract, the day it opens it barely pokes its head above the bract's rims, then after pollination its pedicel bends the maturing ovary backward out of the way, to make place for the next flower. In the picture you can see bent-back pedicels to the right, behind the flower. You may recall similar bracts subtending flowers in various dayflowers, genus Commelina, we've run into. Dayflowers belong to the same family. The way the flowers are cradled inside the folded bracts has given rise to some of the plant's many names -- Boat Lily, Moses-in-a-boat, Oysterplant, Boatplant.

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YUCATAN SPINYPOD
Those of you with me since my hermit days in Mississippi probably were surprised when I came to Mexico and began speaking Spanish. All during those hermit years I'd carried inside me this "other life" -- memories and changes wrought during pre-hermit years of deep immersion in the Latin culture. Well, the same is true about my previous German life. I've spent a lot of time in Germany, and speak that language, too. At one time I was pretty involved in German university life in the towns of Münster, Ulm and Bayreuth. During the last two years of my German life I did botanical illustration at the University of Bayreuth.

The people I was with back then were botanists specializing in a usually overlooked group of inconspicuous, twining plants in the Milkweed Family, the best-known member in North America being Sandvine of the genus Cynanchum. German research grants funded my friend Sigrid and me on trips in several countries in Latin America and Africa as we collected these plants for her PhD dissertation and later habilitation, which is a German post-PhD thing.

I'm mentioning all this so you can visualize the memories evoked, the world of associations, the panorama of feelings and emotions that emerge when here I meet members of the tribe of plants we were so obsessed with back in Germany.

That happened the other day when I noticed the humble little vine with quarter-size flowers shown at https://www.backyardnature.net/n/08/081006dy.jpg.

This plant is common here, twining among cacti, henequen plants and branches of dead trees. They like light. You'd never imagine that they'd have anything to do with milkweeds until you look into the little flowers' throats with a lens, and then you see the pretty complexity there all set down along themes recognizably milkweed-flower.

Sigrid is on sabbatical so I sent the above picture for identification to my friend Ulli back in Bayreuth. He was tickled with the picture, for the little vine, despite its commonness here, is endemic, in the whole world found only in the Yucatán. It's DICTYANTHUS YUCATANENSIS, formerly called Matelea yucatanensis.

The plant is so low-key that I doubt it has any common name. However, Weakley's Flora of the Carolinas refers to species in the genus Matelea as Spinypods, so maybe a good English name for this vine is the Yucatan Spinypod.

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THRESHOLD?
Who knows, but maybe we've reached the threshold past which events of the time speak more convincingly than any words. Since I began this Newsletter in 2001, whenever I've editorialized, basically I've just said the same thing again and again: That Nature teaches us to respect diversity, to recycle and not waste, to be at least semi-self-sufficient, to live frugally and simply, and to focus more on life's spiritual content.

But nowadays anyone can see the foolishness in living beyond one's means, beyond the carrying capacity -- as ecologists say -- of the environment. At this point, directing attention to the strict, straightforward economy Nature practices throughout the biosphere is superfluous.

And yet, maybe one more point needs to be made about the matter, just for those still wondering if their plans for the future, and therefore their current lifestyles, need to change now:

If it is true that all very large, complex systems are structured similarly and behave along the same lines -- something I've often suggest in these Newsletters -- then today's sudden breakdown of many of the world's economies may soon find its counterpart in the biosphere, in the form of sudden planetary biosphere collapse.

For, there's an obvious common denominator between the very large and complex collapsing national economies and the very large and complex planetary biosphere: In both arenas humankind has dumped enormous toxicity, whether toxic bonds, or toxic chemicals.

My advice for those confused by the news is to go sit awhile beside a flowering plant, a birdfeeder or other available touch-point with Nature. Look, feel, reflect, simply spend some time there, and little by little clarity will come. The need for, and the path to, simplicity, self discipline, and love for what IS, will reveal itself the way a flower opens, an egg hatches, a rainbow comes into the sky.

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Best wishes to all Newsletter subscribers,

Jim