JUNE 19, 2016
Nowadays it's easy to see Great-tailed Grackles "sky pointing," as seen at http://www.backyardnature.net/n/16/160619gk.jpg
It's always been assumed that sky pointing was some kind of aggressive behavior that somehow helped grackles sort out among themselves who the dominant individuals were.
In 2007, Elissa Wampler and David Gammon published a paper in The Texas Journal of Science, called "Aggressive head-up displays in great-tailed grackles (Quiscalus mexicanus)." After a lot of field observations and the use of statistics, their main finding was that "Males were much more likely than females to use the display, and males were most likely to use the display in groups of mixed sex." They theorized that sky-pointing may help male grackles achieve higher reproductive fitness, but ended by saying that more studies were needed to determine for sure exactly why the birds did it in the first place.
My guess is that, aside from status reasons, sky-pointing helps show which birds are most interested in whatever they seem to be sky-pointing about, whether it's over a food source, a female, or something else. If you watch sky-pointers for awhile, eventually it becomes clear whose mind tends to roam and who is most focused on maintaining his or her assertion, whatever it is. If I were a female grackle over whom two males were sky-pointing, and one of them began glancing at the ground from time to time, I'd begin favoring the male who was interested enough in me to keep sky-pointing.
Sky pointing is a wonderful way of settling disputes, and I think that we humans might do well to try it. For example, instead of going through such long presidential primaries where all kinds of hurtful things are said and done, let the candidates see who can sky-point the longest. Could it be any less effective than the system we have now?
My friend Iolanda brought me a paper cup in which she'd deposited a black beetle about 1¼ inches long (3cm), which she'd found wandering on a bathroom floor. You can see the critter with its mean looking "pincers" at http://www.backyardnature.net/n/16/160619bt.jpg
A close-up of the head and its pincers, or "jaws," is at http://www.backyardnature.net/n/16/160619bu.jpg
Of course these pictures went straight off to volunteer bug identifier Bea in Ontario, along with my remarks that it might be a tough job to figure this one out, since there's a blue million such beetles and their taxonomy hasn't been well studied.
Still, before long Bea replied that it was a kind of ground beetle, meaning that it was a member of the big Ground Beetle Family, the carabidae. She tended to think it was a member of the genus Pasimachus, and even thought it might be PASIMACHUS CARDIODERUS, known to occur in Mexico, Belize, Guatemala and El Salvador. There's a fine website dealing just with members of the Ground Beetle Family, and there you might like to see if you think our Yucatan beetle looks like Bea's Pasimachus cardioderus, at http://carabidae.org/taxa/cardioderus-chaudoir-1880
Also at that website you might enjoy viewing a page displaying dozens of different ground beetle species, at http://carabidae.org/gallery
All species of Pasimachus ground beetles are wingless, and therefore flightless. In typical beetles the hard, shiny covering of the beetle's back part, its abdomen, is split down the middle, lengthwise. The two hard, shell-like halves, called "elytra," are actually front wings that have evolved to form protective structures over the back wings. When the beetle wants to fly, the elytra separate to expose the delicate hind wings stored beneath them, the hind wings deploy, and the beetle flies away. In the Ground Beetle Family, the elytra are fused into a single rigid shell. Most ground beetles run about under or on leaf litter in forests, their main prey being caterpillars and other larval insects.
Pasimachus cordioderus, which Bea thinks this could be, is nocturnal, hiding during the day beneath whatever it can find. And now we know that sometimes the species might wander into a tropical bathroom.
VARIEGATED FRITILLARIES GALORE
Something special about these days is that, on a healthy clump of Yellow Cosmoses planted beside the hut door, from dawn to dusk every day, normally at least eight to ten orangish Variegated Fritillary butterflies are flitting about, sometimes more. I love sitting nearby watching wondering how they can remain so active in the intense sunlight and heavy heat. You can see the cosmos clump at http://www.backyardnature.net/n/16/160619vf.jpg
In that picture, by the way, also you can see other plantings which get watered daily, and which eventually will be talked about here. At the far right you see lettuce producing seed for planting when the cooler months return, and parsley grows in the woven baskets. Both lettuce and parsley are courtesy of volunteer identifier Bea from Ontario, who brought seeds when she visited here in February. You can see a Variegated Fritillary, EUPTOIETA CLAUDIA, on a cosmos blossom at http://www.backyardnature.net/n/16/160619vg.jpg
One reason so many Variegated Fritillaries frequent the cosmoses is that this is a widely distributed species specializing in open, sunny areas, including fields, pastures, road edges, landfills and such, and thus it's one that benefits -- at the expense of others -- from human disruption of the landscape. Originally Variegated Fritillaries specialized in prairies and other such open natural environments, but nowadays roadsides and flowerbeds next to huts suit them just fine. They distributed from Argentina north through Central America, Mexico and the Caribbean, to most of the US.
Variegated Fritillary caterpillars feed on species of several plant families, including the Passionflower and Purslane Families, which commonly occurr here. Adults take nectar from many kinds of flowering plants, including members of the Milkweed, Dogbane and Sunflower or Composite Family, which are abundant here.
FALSE TAMARIND FLOWERING
Last year at this same time, on the northern Yucatan coast at Río Lagartos, I reported on flowering False Tamarind, Lysiloma latisiliquum. Now it's also flowering here, but I'm noticing small differences between our trees and those on the coast. The ones here in the central Yucatan seem to be the more commonly encountered type. I want to post the following pictures to help others understand the variations, and maybe to set off a discussion about the non-standard type documented up at Río Lagartos. Our page with the Río Lagartos photos is at http://www.backyardnature.net/yucatan/tsalam.htm
The subdivisions of our Chichén Itzá tree's twice-compound leaves bore more pairs of leaflets than the Río Lagartos ones, as shown at http://www.backyardnature.net/n/16/160619ll.jpg
The corollas of our False Tamarinds and others I see on the Internet are pinkish, while those at Río Lagartos were greenish white. Our pinkish ones are shown at http://www.backyardnature.net/n/16/160619lm.jpg
False Tamarinds are very nearly acacias, and in the past were considered to be acacias. One feature that False Tamarinds have that acacias don't is very large, leafy stipules at the base of new leaf petioles -- these were also present on the Río Lagartos trees -- as shown at http://www.backyardnature.net/n/16/160619ln.jpg
Atop leaf petioles, just like the Río Lagartos ones, our trees bear glands, possibly secreting compounds that attract ants that help defend the tree against herbivores. A gland is shown at http://www.backyardnature.net/n/16/160619lo.jpg
Beneath our Chichén Itzá tree lay many legumes from the last season, some shown at http://www.backyardnature.net/n/16/160619lp.jpg
The Río Lagartos tree grew in very thin soil and was scrubby and low-lying, along with other stunted tree species that in thicker soil and where there's more rain make regular trees. You can see the well formed trunk of our Chichén Itzá tree at http://www.backyardnature.net/n/16/160619lq.jpg
Down here even the most informed field workers are still struggling to figure out what's what in the natural world, so documentation like this really has some value for them.
Besides, for me at this point in my life, few things are more appealing than describing a tree.
Last December we found a poorly documented small tree endemic just to the Yucatan Peninsula, which we called Gaumer's Velvetseed, Guettarda gaumeri. It was a member of the Coffee Family, the Rubiaceae, and at that time it was producing pea-sized, spherical, fleshy, very bright red fruits. The tree's leathery, hairy leaves and its colorful fruits are shown at http://www.backyardnature.net/mexnat/guettard.htm
Since the tree is so poorly known, this week I returned to the same area, hoping to find it in flower, and I was successful. You can see its small, pale yellow flowers clustered among hairy, dewy-wet leaves at http://www.backyardnature.net/n/16/160619gu.jpg
The flowers usually occurred in pairs, each with its own pistil and calyx. A side view of two flowers with four corolla lobes arising from each corolla tube is at http://www.backyardnature.net/n/16/160619gw.jpg
A shot into a flower's mouth finding only two anthers visible at the stigmas level is at http://www.backyardnature.net/n/16/160619gv.jpg
Toward the end of the rainy season, in November or so, big, white blossoms form on small trees along roads and at woods edges. The flowers look like large wild roses, only white, and a curious feature about them is that their white petals normally are bruised looking, with brown patches. These are Luehea trees, Luehea speciosa, whose page showing flowers and leaves is at http://www.backyardnature.net/yucatan/luehea.htm
A good field mark for Luehea speciosa is that its broadly oval leaves are white-hairy below, shown at http://www.backyardnature.net/n/16/160619lv.jpg
Nowadays Luehea fruits are turning up, shaped like small, brown, hairy, American-type footballs, as shown at http://www.backyardnature.net/n/16/160619lu.jpg
The capsular-type fruit is shallowly ribbed. Another Luehea species occurs in the area, but its fruits are much more conspicuously ribbed. At maturity the capsules split at their far ends into five or so "teeth," which spread apart, allowing seeds to escape from inside the capsule when something such as wind shakes its branch.
Luehea speciosa fairly commonly occurs throughout nearly all of humid, tropical America, and in many places it's regarded as medicinal.
The online Biblioteca Digital de la Medicina Tradicional Mexicana reports that in Veracruz State, to treat diarrhea, one boils three 10x20cm sections of bark in one liter of water, and takes half a cup of the resulting tea three times a day. For snakebite, make the above brew but with an added 20cm of Guaco root. Drink half a cup of that brew every three hours for the whole day. I suppose they know what Guaco is in Veracruz.
Last summer when I lived in the little Maya village of Yaxunah 20 kms south of Chichén Itzá, I saw that many of the town's farmers grew a member of the Arum or Jack-in-the-pulpit Family, the Araceae, which they called Makal. It's very similar to the big Arrowleaf Elephant Ears, Xanthosoma sagittifolium, presently outside my hut door, only very much smaller, and seldom if ever flowering. You can see me standing beneath an Arrowleaf Elephant Ear leaf at http://www.backyardnature.net/yucatan/elephant.htm
In Yaxunah and elsewhere in the Yucatan, I've not seen the Maya growing large plantings of Macal, but rather they scatter a few plants around their houses or next to their their cornfields/milpas, or both places. Everyone knows that Macal tubers are edible, and they're pretty good when cooked, a little like boiled potatos, but nowadays people are gravitating away from such traditional foods, toward Coca-Cola and store-bought food. Macal is considered "poor-folks' food." The Arrowleaf Elephant Ears by my hut don't produce tubers.
Until now I've not commented on Makal in the Newsletter because I've always been unsure exactly what Makal is. For some years I waited to stumble upon a flowering plant -- flowers usually are the key to identification -- but now I'm thinking that Makal just doesn't like to flower, or it can't. The Arrowleaf Elephant Ears outside my hut flower readily, though their ovaries seem to abort and no fruits result. Makal doesn't even seem to try.
A few weeks ago, in mid April when I was in the Lacandon community of Lacanja Chansayab in Chiapas's Lacandon Reserve in extreme southeastern Mexico, I saw what looked like a belly-high Makal growing along a trail, and photographed it. It's shown at http://www.backyardnature.net/n/16/160619mk.jpg
I'm bringing Arrowleaf Elephant Ears into the discussion about Makal because of whats said on an excellent web page on root crops of the Maya, in Spanish, produced by the Autonomous University of Yucatán, UADY, at http://www.mayas.uady.mx/exposiciones/exp_044444.html
There I read that the root crop Kukut Makal, which I'm just calling Makal, is Xanthosoma yucatanense, but that probably that name is just a synonym for Xanthosoma sagittifolium -- which is Arrowleaf Elephant Ears.
So, is the Lacandon plant Makal, and is Makal a cultivated form -- a cultivar -- of Arrowleaf Elephant Ear?
An important field mark separating Arrowleaf Elephant Ears from other look-alike plants is that its leaves' petioles attach to its blades in a certain way, which you can see at http://www.backyardnature.net/n/11/111120xo.jpg
On the Lacandon plant in Chiapas, the sinus connection is a little different, as shown at http://www.backyardnature.net/n/16/160619ml.jpg
The FAO produces a very informative page on Xanthosoma sagittifolium -- which they call Tannia or Yautia -- at http://www.fao.org/docrep/T0646E/T0646E0o.htm
There it's said that the cultivation of Xanthosoma sagittifolium may have originated in northern South America and spread through the Caribbean area and Central America. When Europeans arrived on the continent, it was already known from southern Mexico to Bolivia. They also write that domestication may have occurred in various places and with different materials, with different goals in mind.
The paper also says that there's enormous variability among the group of Xanthosoma sagittifolium-like edible plants, with some cultivars not assignable to any formally recognized species or cultivar name. Moreover, since seeds are seldom produced, reproduction is almost entirely vegetative. The paper sums up the name situation by saying that in recent years the tendency has been to give the name Xanthosoma sagittifolium -- Arrowleaf Elephantears' name -- to all cultivated clones of Xanthosoma, at least "... until a modern revision of the genus clarifies the taxonomic situation of the species mentioned."
I think that with regard to Makal's "real identity," that's about as far as I can go. The Lacandon plant is larger than Makal seen here in the central Yucatan, but that may be because there's more rainfall and the soil was richer in that part of Chiapas than here.
PURPLE ORCHID TREE
In May we looked at a hybrid Purple Orchid Tree blossoming here at Hacienda Chichen. That page is at http://www.backyardnature.net/mexnat/blakean.htm
Earlier we'd seen one of the hybrid's parents, Bauhinia variegata, so it was interesting to compare the two taxa. Our page showing the parent's very rose-purple flower is at http://www.backyardnature.net/mexnat/bauhin-1.htm
This week another flowering orchid tree turned up, but its flowers were white with only a purple splotch and some purple along the petals' margins. With a thatch-roofed hut in the background -- not the one where I live -- this week's white-flowered orchid tree is shown at http://www.backyardnature.net/n/16/160619ba.jpg
The tree bore maturing, legume-type fruits, so clearly it wasn't a form of the hybrid, which is sterile. You can see the white-flowered tree's eight-inch-long fruit (20cm) at http://www.backyardnature.net/n/16/160619bb.jpg
So, was this white-flowered tree the other commonly planted orchid tree, Bauhinia purpurea?
Fortunately, there's a 2014 PDF document by José Manuel Sánchez de Lorenzo-Cáceres freely downloadable on the Internet, with excellent pictures and a good identification key that made our tree easy to identify. You can search for the document's name, "Notas sobre Bauhinia purpurea L., Bauhinia variegata L. y su híbrido Bauhinia x blakeana Dunn (Leguminosae-Caesalpinioideae)."
Two easily visible features separate Bauhinia purpurea from Bauhinia variegata. In Bauhinia purpurea, the cowhoof-shaped leaves are divided for 1/3-½ their length, while those of Bauhinia purpurea are divided only ¼-1/3 their length. You can see a leaf from our hut tree at http://www.backyardnature.net/n/16/160619bd.jpg
Our tree's leaves were divided ¼-1/3 their length, so that's a vote for Bauhinia variegata.
The other main feature is that Bauhinia purpurea flowers produce only three fertile stamens, while Bauhinia variegata produces five. A close-up of our tree's stamens is shown at http://www.backyardnature.net/n/16/160619bc.jpg
Along with the large, greenish pistil pointing upward, there are five stamens with white, curving filaments tipped with brown, arrowhead-shaped anthers, so that's another vote for Bauhinia variegata.
So, now we know that there's considerable difference in flower color in this much-planted tropical tree from southeastern Asia.
ROBINS & HAWKS
I first arrived at Hacienda Chichen in late 2009, and stayed until late 2012. While I was gone, sometimes I liked to remember how pleasant it'd been in the Hacienda's thatch-top, pole-walled, dirt-floored Naturalist-hut. One of the most agreeable times of all had been at dawn and dusk during those weeks of the year when untold numbers of Clay-colored Robins -- also called Clay-colored Thrushes -- called at the same time. A gently effervescing, ebbing and flowing but unceasing ocean of soft melodies, chortlings, burblings, trills, mews and whistles all made a sweet music that made you smile and want to listen. Pictures and plenty of text about the plain-looking but sublimely melodious robin/thrush are at http://www.backyardnature.net/mexnat/turdgray.htm
Here the Clay-colored Robins' callings are at their peak now, and I keep telling the tourists and reminding myself how special and beautiful it is.
And yet, also from time to time a kind of blood-curdling snarl erupts from a dead snag in an abandoned field far beyond the robins' woods. It's the local Gray Hawk, and I have to admit that his call, in its own way, is just as appropriate, just as evocative, and just as worthy of admiration as the robins' calls.
In fact, at certain stages of my life, I identified most with the hawk's snarl, and might have found the robins' calls pleasant but monotonous, and in general not harmonious with my wandering-viking spirit of that time. Even at my age now, if I lived in a vast suburb of look-alike houses with myself and everyone I knew stuck in exhausting, narrow, unfulfilling routines, maybe I'd feel so repressed and wasted that I'd favor the hawk snarl, and fantasize about attack and destroy. But, if I lived in a loud, crime-ridden inner city, probably I'd habitually crave the robins' daily meditations, the same calm, peaceable melodies repeated again and again.
So, that's interesting. We have two opposite birdsong moods, and we humans can be flexible enough to prefer one extreme over the other, and sometimes like both extremes at the same time.
Also, it seems to me that normally when a person invariably craves just one extreme of anything over its opposite state, either it's because that individual still is very young and "going through phases," or else it's because of an imbalance in that person's life, or a feature of that person's personality that diverges considerably from that of average people. In my experience, when the average healthy, mature person acquires enough experience of the world, and has enjoyed enough time and personal space to reflect on matters, that person automatically comes to think of the robins' warblings and the hawk's snarl as equally beautiful and good to hear, just beautiful in different ways.
Moreover, it seems that this general principle applies to untold numbers of pairs of opposites, not just robins and hawks, and not just things but also abstractions. Maybe it's a kind of natural law that when an evolving sentient being matures in an environment permitting introspection and general cogitation, the tendency to assign "good" and "bad" tags to members of opposite pairs changes to a whole new system of seeing the world.
In this new system, when one beholds opposite situations, one just says, "Oh, so that's how it is. How interesting. And, maybe, in the broad view of things, how pretty... "
Best wishes to all Newsletter readers,
All previous Newsletters are archived at http://www.backyardnature.net/n/.