July 18, 2010
BASILISK LAYING EGGS
Monday at about 3 PM I stepped from my hut door and there about eight feet away was what's shown at http://www.backyardnature.net/n/10/100718bk.jpg.
It was a Striped Basilisk, BASILISCUS VITTATUS, about 1-½ feet long (45 cm) laying an egg in a freshly dug nest. Our much larger Black Iguanas often let me get this close but basilisks usually run away at this distance. This lizard obviously didn't want to abandon her open nest so she just froze there as I reached for my camera and steadied it with a pole. The moment I snapped the picture and took a step nearer for a closer shot, however, she scrambled away in a blur. You can see the nest exactly as she left it at http://www.backyardnature.net/n/10/100718bl.jpg.
Though she'd chosen a spot strewn with a thin layer of loose soil, when I ran my finger around the nest's rim I found that the ground just below the loose soil was hard packed. How did she dig such a neat hole in such hard ground? After I'd been away for about half an hour I returned to find the nest filled with earth and so well camouflaged that really I couldn't decide exactly where it had been.
Jonathan Campbell reports that Striped Basilisk eggs are 2/3 inch long (17mm) by 0.4 inch (11 mm and that the average number of eggs per nest is about four. Five are visible in the picture and by the way they're stacked you almost suspect a sixth below. Campbell says that the gestation period is 50-55 days, so around September 1 I should start looking for baby basilisks. However, Campbell also reports that it's estimated that only about two percent of a nest's hatchlings survive for two years. In captivity they've lived for five years and eleven months.
Lots more info on Striped Basilisks is available at http://www.backyardnature.net/mexnat/basilisk.htm.
As I walked across the open area in front of the workshops returning a wheelbarrow one of the fellows asked if I wanted to see some nestlings. He pointed at a Sabal Palmetto (fan palm) trunk very shaggily mantled with the dried-up bases of old frond petioles, but I saw nothing. He had to walk up to the tree and point to exactly where the nest was before I saw it, and you can see it snugly beneath an old petiole base at http://www.backyardnature.net/n/10/100718nf.jpg.
The petiole base very nicely sheds rain from our almost daily afternoon showers or downpours. A close-up showing what the arriving parents see is at at http://www.backyardnature.net/n/10/100718ng.jpg.
These are Yellow-throated Euphonias, regularly seen around the Hacienda. Euphonias are small tanagers and are known to build globular nests with side entrances exactly as shown in the picture.
As I was knocking around taking the above pictures the nestlings, even though they had somewhat glassy-looking eyes open, remained in plain view begging, apparently depending on the theory that any activity without signified a parent approaching with food. Later that day, however, when I went to check on them, my movements caused them to cower out of sight in the nest's bottom. Just in those few hours, had they matured enough to change their behavior so drastically?
SONGBIRD NESTLING DEVELOPMENT
The above question about whether the nestlings might have matured so quickly sent me to the Internet. There I found a document issued in PDF format by the US Fish & Wildlife Service called "A Guide to Nestling Development and Aging in Altricial Passerines," which sounded perfect, since euphonias are Passerines. You can download that free, well illustrated document at http://library.fws.gov/BTP/altricialpasserines07.pdf.
The document's title refers to "altricial passerines." Altricial species are those producing nestlings requiring a great deal of parental feeding and other attention upon hatching. Altricial nestlings upon hatching are relatively immobile, lack down, and often have their eyes closed eyes. Most songbirds are altricial passerines.
The opposite of an altricial species is a "precocial" one. Ground-nesting birds such as ducks and turkeys produce precocial nestlings ready to leave the nest in one or two days.
Upon hatching, most altricial nestlings have smaller brains than precocial ones, but the brains of altricial species keep maturing longer so that the adult birds typically end up with larger brains than their precocial counterpart, and exhibit correspondingly more sophisticated behavior.
The above document mostly dealt with feather development and didn't help with my crouching question. It did help me recognize, however, that the dead nestling I found on the Hacienda's steps that same day probably had just hatched. You can see that sad but interesting picture showing very well an altricial species' closed eyes and featherlessness, at http://www.backyardnature.net/n/10/100718ne.jpg.
I don't know what species the nestling is, but Social Flycatchers are very common in the area where it was found.
THE r/K SELECTION THEORY
These nestling experiences have gotten me thinking about the r/K Selection Theory which, loosely interpreted, relates to the trade-off between producing lots of offspring with a low probability of surviving to adulthood ("r-selected species"), as opposed to a few ones who have a better chance at staying alive ("K-selected species").
r-selected species tend to live in unstable environments, produce many offspring that disperse widely, mature early, have a small body size, and live relatively briefly -- weeds are a good example. K-selected species tend to occupy stable environments, produce few offspring, be relatively large, and live relatively longer -- Sequoia trees in protected mountain coves are good examples, and humans. Each offspring of a K-selected species, whether it is a seed, nestling or a higher primate baby, requires more "preparation" by the parents before they are set into the world.
The concept's variables are expressed algebraically in the Verhulst Equation of Population Dynamics shown at http://www.backyardnature.net/n/10/100718dk.gif.
In that equation, r is the growth rate, K is the environment's carrying capacity and N is the population size. These terms are generally recognized by those acquainted with standard ecological algebra.
This is not a case of something in Nature being summed up completely and elegantly in a tiny equation. There's a continuous spectrum of species between the r and K extremes, so by no means do all species fall into one or the other categories. Also, some species display both r- and K-traits. For example, sea turtles are large and have long lifespans but they produce many unnurtured offspring.
What's interesting in the context of precocial and altricial bird species is to consider whether altricial birds, whose parents invest a lot in their upbringing, fit the description of K-selected species, while precocial bird species, whose parents are much less involved in providing care, fit the mold of r-selected species.
Consensus seems to be that there's a certain correlation between the two concepts, but so many exceptions can be thought of that it's debatable whether it's useful to link them.
The other day one of the staff asked if I'd seen the big "langosta" found in the laundry room. In Spanish langosta can mean either lobster or grasshopper so I halfway knew what to expect. Still I was unprepared for the size of what turned up. You can see it at http://www.backyardnature.net/n/10/100718gg.jpg.
That's the biggest grasshopper I've ever seen, about four inches long (10 cm). A study of the head area is at http://www.backyardnature.net/n/10/100718gh.jpg.
Volunteer insect identifier Bea in Ontario quickly pegged it as the aptly named Giant Grasshopper of the genus Tropidacris. With that help and from pictures on the Internet I ws able to guess that it's TROPIDACRIS CRISTATA ssp. DUX, formerly known as T. dux. In an online research paper I read that members of the genus Tropidacris are the largest known of all grasshoppers, and that they're well known where they occur because of their bright colors and their destruction of wild and cultivated plants.
I like to just gaze at the features shown in that head picture, letting the anatomy's otherworldliness and elegance soak into my spirit. What you see is as exotic as anything that could be thought up for a science fiction movie, yet these creatures are around us all the time, and maybe they'll survive even if humans don't. Maybe someday Earth's dominant lifeform will look more like it than us, and then what kind of poetry and music will there be?
I asked José the shaman if this grasshopper was of any special significance to the Maya and was surprised when he said "¡Nada!" -- "nothing!"
MULE EAR ONCIDIUM
Deep in the forest atop a low mound you might not guess once was a Maya structure, one never excavated so maybe still holding secrets, a little orchid in full bloom grew in dim light on the side of a tree. You can see it with its many thumbnail-size flowers at http://www.backyardnature.net/n/10/100718on.jpg.
That's ONCIDIUM CARTHAGENENSE, sometimes placed in the genus Tricocentrum, widely distributed from Mexico and the Caribbean to northern Brazil. Because of the leaf's shape and because often two leaves arise together, some of its names translate to "Mule Ear." Oncidium is a big, well-known genus including many species fancied by orchid growers, so a good English name for the species is Mule Ear Oncidium.
Mule Ear Oncidiums are typical of the genus. Back in Querétaro we met another species, Oncidium cebolleta. It's seen at http://www.backyardnature.net/q/oncidium.htm.
Many orchid genera produce flowers at the end of a stem arising from the plant's center. Oncidiums are different from them in that they produce special inflorescences, or flowering heads, on stems arising apart from the tufted leaves. Also, the stems of inflorescences of many genera keep growing year after year, but Oncidium inflorescences do all their growing in a single year. Many orchid species sprout their inflorescences and leaves from conspicuous, more or less egg-shaped, water-storing, photosynthesizing parts of the stem known as pseudobulbs. Oncidiums don't have pseudobulbs.
You can see front and side views of a flower at http://www.backyardnature.net/n/10/100718oo.jpg.
Among the flower's most easily observable features distinguishing it as an Oncidium blossom is that its lower lip is well attached to the rest of the flower -- not movably jointed. Also, the lip bottom flairs making it somewhat fan-shaped. The lips of many Oncidiums are three-lobed, but this species is only two-lobed. Finally,where Oncidium blossom lips attach to the rest of the flower, there are wart-like "cushions" or "callosities," showing up as a darker purple in the frontal picture at the left, and as a forward-projecting bump on the side picture at the right.
So, if you're halfway interested in neotropical orchids, the genus Oncidium is one of a handful you really ought to know, and the above distinguishing features for the genus are worth keeping in mind.
The other day Hacienda Chichén's Chef Cime invited me to lunch at his home in the village of Kaua just east of here. Most Maya villages around here developed around a cenote, or big sinkhole with water in the bottom of it, and Kaua is no exception. When you go to Kaua, you just have to visit the cenote. I was glad to do so because in cenotes often you find moisture- loving plants not found in the drier environment above.
For example, there was the flowering woody vine shown at http://www.backyardnature.net/n/10/100718tf.jpg.
This is TOURNEFORTIA VOLUBILIS, of the Borage Family, the Boraginaceae, the same family that holds the North's herbaceous bluebells, forget-me-nots and garden comfrey. The species also grows in southern Texas and Florida so it's known by the English names of Twining Soldierbush and Twining Tournefortia. What especially caught my eye about this vine was its pea-sized, white, black-spotted fruits, shown at http://www.backyardnature.net/n/10/100718tg.jpg.
Identification of the species was made easier because I could guess that the vine was a Borage Family member. The main cue for that was how the flowers and fruits grew in a zigzag fashion along one side of the inflorescence branches -- not spirally arranged, which is more typical. Also, the tips of the inflorescence branches tended to curve like a scorpion's tail. Such inflorescences are said to be "scorpioid." This trait also occurs in a few other families, but in this part of the world if you're dealing with a woody vine, the best bet is Borage Family.
Tourneforita volubilis is found from southern Texas and Florida south through Mexico, the Caribbean and Central America to northern South America. Otherwise not much information seems to be available about the species, so here we can at least announce to the world that it's here.
HIPPOBROMA LONGIFLORA'S LONG WHITE FLOWERS
Down in the cenote's bottom where it was even more humid, in the mud there grew the knee-high herb with four-inch long (10 cm), white flowers shown at http://www.backyardnature.net/n/10/100718hp.jpg.
At first I had no idea what this might be but when I noticed how the flowers' five grown-together anthers extended from the corolla tube and curved up a little, just like anthers of the North's lobelia flowers, I figured it might be a Lobelia Family member. Checking genera in that family listed for the Yucatan it was easy to come up with the name.
It's HIPPOBROMA LONGIFLORA, in English often called Star of Bethlehem, but that name is more commonly applied to other plants, so it's an awkward one. Just call it Hippobroma. Nowadays the Lobelia Family has been lumped with the Bellflower Family, the Campanulaceae.
Damaged leaves and stems of this plant issue copious milky juice, which accounts for the Spanish name, "Lágrimas de San Diego," which means St. James' Tears. The juice is rich in two well known and powerful alkaloids, nicotine and lobeline, which affect human nervous systems similarly. Small doses of the juice may have medicinal value, but too much can induce vomiting, muscle paralysis and trembling. One web page advises wearing gloves when handling the plant since the sap can be absorbed into the skin and cause the above effects. Also, a little in the eyes can cause blindness. Medicinally, various cultures have learned to apply the plant to wounds to cauterize wounds and promote healing. It's been used to treat venereal diseases, asthma, bronchitis, "rheumatism," and even epilepsy and hydrophobia.
Hippobroma longiflora is native and endemic to the West Indies, but has become an invasive all through the American tropics and Oceania.
HORSEFLIES & RACHMANINOV
Whistling "As Time Goes By" from the old Humphrey Bogart movie Casablanca I enter the dirt-floored hut, summon Rachmaninov's Cello Sonata Opus 19 onto the computer, bring her picture onto the screen and mix myself a stiff pozol, the Maya drink of water and cornflour. I stare at her as the robins' singings just beyond the pole walls mingle with earnest cello and piano. A horsefly drawn by the light lands on the computer screen right atop her lovely ear and as afternoon thunder rumbles deeply on a purple horizon and Rachmaninov's melodies keep knotting up and disentangling I sit sweating and gazing, the odor of mildew drifting up from stained and tattered shorts, and the looming storm's first lightning flickering between the hut's pole walls.
What a thing to be alive and to feel all this, and even to be ready for more once Bogart and Rachmaninov have had their say, the chilly rain has run the horseflies off and the odor of mildew is replaced by the fragrance of the forest's wet herbage and the mud around the hut. I am alive, and memories of this woman haven't killed me yet, and after the rain there will be swallows in the sky and maybe a few rays of sunlight before sunset, and frogs croaking, and maybe then it'll be Bach and Mississippi Leadbelly singing the blues, me lying there inside the mosquito net on raw cedro boards smelling tragically and honestly of resin.
Alive, alive and yearning, not really worried about my time running out because anymore I'm not even sure time exists or that "I" am something apart from everything else with a beginning and an end, just alive, feeling, looking around, soaking in, digesting, holding on, very, very alive.
Here's why I'm telling you all this: This kind of being alive I've come to only after a great deal of simplification and getting rid of stuff. In previous more cluttered, secure and comfortable lives I've tried living exquisitely but always distractions and the laziness that accrues to security and comfort kept me from it, took the edge off things, and of me.
Is the horsefly/Rachmaninov kind of living better than the coffee-maker, big-TV-on-wall one? Except that my style impacts the planetary biosphere much less destructively than a life in which consumption of goods and services is a main feature -- in which case it is indeed better in an important way -- I'd say no. That's because I believe in diversity, so if others have different priorities and choose different living styles, that difference not only is to be respected, but cherished.
However, the world is hog-gung-ho awash with messages that we all must consume, consume, consume, and that's killing the planet. So here are words from a different world, one of biting horseflies, Rachmaninov, pozol and that goodbye woman with her gypsy dresses and two- toned eyes:
Simplify, simplify, simplify, then with what's left over, savor, savor, savor!
Best wishes to all Newsletter readers,