May 12, 2007

CLAY-COLORED ROBINS BUILDING NESTS
One of my favorite hiking destinations lies at the far end of the reservoir, about 45 minutes away, where the valley narrows, the lake becomes a trickling stream, and Bonpland Willows and Mexican Sycamores create a shadowy woods. Livestock trails paralleling the stream take me through the woods. Beneath every big tree there's always a comfortably rounded boulder you can sit on, and always the birds are putting on a show.

This week Clay-colored Robins have been particularly vocal and busy. They hop on the ground tossing litter aside with their bills just like American Robins. When worried about something they issue nasal clucks the way nervous American Robins do, and their body shape and size is just like the American Robin's. The only obvious big difference between the two species is that the Clay-colored's drab plumage shows only hues of brown. You can see some pictures of the species at http://fireflyforest.net/firefly/2006/06/10/clay-colored-robin/.

If your computer can handle WAV files you can hear one by clicking on the "play" button on the blue thing here.

This week I watched a Clay-colored Robin starting the building of her nest with what appeared to be dried-up willow rootlets left hanging on dry banks, now that the water is so low. I read that the finished nest will have a middle layer of mud. The species lays 2-3 pale to bright blue eggs, and may produce two broods. I also read that Clay-colored Robins eat earthworms, slugs, insects, fruits, and sometimes lizards. They follow army ants and feed on small animals trying to escape the ant columns.

Clay-colored Robins are so reminiscent of American Robins that I just assumed that, as with the American Robin, the Clay-colored male would claim and vigorously defend a territory, while the female nested somewhere within it. Therefore, this week, what I saw didn't make sense.

Around the tree where the female Clay-colored Robin was building her nest I saw three other Clay-colors doing various things. Moreover, as I continued up the valley I passed through several clusters of the species. I heard lots of singing and saw some courtship behavior but most robins seemed to be doing nothing special. In fact, what stuck me was that nowhere could I see territory-boundary disputes taking place, and clearly there were no territories being claimed by exclusively male-female family units. This was a situation to place before Google.

On the Internet I found no comprehensive description of Clay-colored Robin behavior, but I did find brief references and side remarks that gradually presented a picture.

In an online article of the journal The Condor,at http://www.princeton.edu/~hau/ReprintLinks/2003Condor105.pdf I found the Clay-colored Robin's social system described as "mating aggregations, leks," and its territoriality as "short, local display court." In the same paper I read that Clay-colored Robins "display in groups."

That word "lek" refers to an aggregation of males, each seeking to attract a mate, and each displaying fervently. It's assumed that "lekking" groups attract more females than do isolated males, and probably this helps the females better compare their potential mate.

Another online article referred to Clay-colored Robins as "polygynous," and yet another called them a "potentially polygynous (lekking) species." In biology, polygyny is a mating practice in which the male takes more than one female sexual partner.

Digesting these laconic and somewhat cryptic lines gradually I conjured an idea of what I'd seen among the Clay-colored Robins that day.

I would guess that that morning the livestock trail along the stream took me through one "mating aggregation" after another, each group consisting of one to several females and a male, and maybe there were "surplus males" weaving in and out of groups as opportunities arose.

That's just a guess, though. The only thing for sure is that at first glance Clay-colored Robins may remind us a very great deal of American Robins, but by no means do their mating activities come close to how Northerners expect a good robin to behave.

*****

THE RUE IN DON GONZALO'S EAR
The other day Don Gonzalo's helper, Silvestre, was watering plants as I walked by. Smiling broadly he stopped me, plucked a sprig from a tender-looking, bluish green herb being watered, rolled up the sprig (a penetrating medicinal odor suffused the air during the demonstration), stuffed it into his ear, and told me that this is how people around here cure earaches. Of course I wanted a picture, but Silvestre was bashful before the camera. We called over Don Gonzalo, who seems to relish being my model, so now you can see Don Gonzalo with this herb expertly tucked into his ear at https://www.backyardnature.net/n/07/070512rv.jpg.

You can see the earache herb itself at https://www.backyardnature.net/n/07/070512ru.jpg.

Don Gonzalo and Silvestre call the plant Ruda. In English it's Rue, and in Latin RUTA GRAVEOLENS. It's a member of the Citrus Family, the Rutaceae. Originally it's from southern Europe but it's planted in gardens worldwide, and often escapes or persists.

When I was gathering information for the Medicinal Plants page of my Traditional Mexican Markets Website, at http://www.mexicanmercados.com/produce/mediherb.htm I found that Rue is one of the most powerful plants in the traditional Mexican pharmacopoeia. The first thing I learned about it was that it is used to induce menstruation and to abort unwanted fetuses.

I also learned early that the tender-looking little plant is so powerful that it's dangerous. A warning at http://www.floridata.com/ref/R/ruta_gra.cfm reads:

That site also informs us that the Rue leaf was the model for the Suit of Clubs in playing cards.

Why would the Rue leaf be honored with such a position on playing cards? Surely it's because in earlier times Rue was so recognized as powerful medicine that it also acquired renown for its magical properties. It was used as a defense against witches. Michelangelo and Leonardo da Vinci are said to have eaten rue to enhance their creativity and eyesight. Rue symbolized regret, sorrow and repentance, and Catholics put sprigs of it in holy water sprinkled on worshippers. At http://www.botanical.com/botanical/mgmh/r/rue---20.html you can read Mrs. M. Grieve's extensive review of its traditional uses, as of about a hundred years ago.

Is Rue really an effective medicinal herb? Don Gonzalo says it makes a good-tasting tea with no side-effects, so one wonders.

But, at http://www.herbmed.org/Herbs/Herb63.htm we read that "Treatment of 15 patients with intracranial tumors, using Ruta 6 from Ruta graveolens and Ca3(PO4)2 showed that 6 of the 7 glioma patients had complete regression of tumors and thus in combination they are used in brain cancers, particularly glioma."

Googling the keywords "'ruta graveolens' medicinal" I get 101,000 returns.

Whatever the case, I'm glad Rue is growing near my casita, just in case I ever get an earache.

*****

SPANISH PLUMS IMPOSSIBLE TO IGNORE
If you ride down a road anyplace in this area two trees are more eye-catching than all others, both planted around people's homes: First, there's the awesomely crimson-blossomed Poinciana I told you about last week, and; second, there's a fruit tree with perfectly leafless branches very heavily loaded with oval, green, inch-long fruits. You can see a typical one of these at https://www.backyardnature.net/n/07/070512sp.jpg.

There's a close-up of three green fruits, which will turn yellow upon maturity, at https://www.backyardnature.net/n/07/070512sq.jpg.

Mexicans call the tree "Ciruelo," which translates to "plum," but the fruit is unlike what North Americans think of as a plum. In other parts of Latin America it goes by the name of Jocote. In English we call it Spanish Plum, Mombin, and other names. There's a species with both yellow- and red-fruited forms, Spondias purpurea, and there's another closely related species, Spondias mombin, which produces only yellow fruits. In Spondias purpurea flowers and fruits occur along the stem, while in Spondias mombin they're clustered at the end of the branch. Therefore, what we have above is the yellow form of Spondias purpurea. These are members of the Cashew Family, in which we also find mangos, sumacs and Poison Ivy. Spondias mombin is native from Mexico to northern South America but is planted worldwide in the tropics.

One reason the species is so popular is that its fruit can be eaten raw, used in preserves, made into jellies and, maybe most popular, used as the base for a sweet drink. I find its taste OK, but not to be compared with something like a fig or an apple. The trees ubiquity here may rest mainly on the fact that it doesn't need much care and thrives on marginal soils. One weakness is that it doesn't tolerate frosts.

Spanish Plum has been grown for so long that several horticultural varieties have emerged. The red-fruited form seems to receive top billing on the Internet, but the yellow-fruited one is much more common here. Also there are purple ones. Don Gonzalo says they taste pretty much the same.

You might enjoy reading the report of Allison Miller, a graduate student at Washington University in St. Louis, who traveled through Central America studying domesticated Spanish Plum populations. Allison found populations adapted for service in orchards, around people's homes, as living fences, cultivated in forests, as well as a few wild populations. Her interesting story, with pictures, is at http://www.mobot.org/MOBOT/Research/jocote/jocote.shtml.

*****

BROMELIAD FRUITS
The most abundant bromeliads in trees along the reservoir road are fruiting now, as you can see at https://www.backyardnature.net/n/07/070512tf.jpg.

That's the same species I introduced flowering in this year's April 28th Newsletter. I'm supposing it to be TILLANDSIA SCHIEDEANA. Last month's flowering picture is at https://www.backyardnature.net/n/07/070428tl.jpg.

In the more recent fruiting picture, the item on a slender stem looking a little like a wad of spaghetti on a fork, at the top, left, is a fruit pod that has split open and is releasing masses of slender seeds bearing long, white hairs. The hairs catch breezes and disseminate the seeds much in manner of how dandelion and thistle seeds get blown about on their white "parachutes." In the picture you can barely make out slender, pale-brown seeds enmeshed in white fuzz.

Last month this species was very pretty with its inflorescence's bright, red bracts and yellow corollas, but now the plants are dried-up, dusty, and cobwebby. Instead of one parachuted seed at a time abandoning its pod, most typically a puff of wind jars loose a whole gob, which catches on the plant's own blades or, more commonly, in spider webs, as shown in the picture.

North America's Spanish Moss, also a member of this genus Tillandsia, produces similar hairy seeds and I've often wondered how such airborne seeds manage to land on a tree limb just right so that the seed eventually germinates and issues anchoring roots. After seeing what happens with our seeds, now I'm imagining masses of fuzz-entangled seeds catching on spider webs, rains come and the whole mess sags onto branch bark, creating a kind of microclimate-producing seed-hair/ spider-web compost capable of retaining enough moisture to help a tiny seed germinate. Maybe spider webs aren't necessary for this scenario, but from what I'm seeing they assist the compost-forming process more often than not. Maybe this is a mutualistic relationship where spiders find homes among the bromeliads, and bromeliad seeds are helped in their sprouting by the spiders' webs.

Not all members of the Bromeliad Family, the Bromeliaceae, produce dry capsules that split at maturity like ours in the picture. The family divides into two large groups, one group forming dry capsules but the other creating berries. The most famous bromeliad is the Pineapple, which produces berries. The part we eat is not that berry, though the berries with their aborted ovules are imbedded in what we eat.

*****

HUSK TOMATOES/ TOMATILLOS
In restaurants here typically you have placed onto your table a little wicker basket filled with hot tortillas draped with a white, embroidered cloth, plus they also bring a small, rusty-red, ceramic bowl filled with hot- sauce. Good restaurants give you two bowls, one with green hot-sauce and the other with red.

In Mexico the green hot-sauce is based on fruit of the plant known by the Latin name of PHYSALIS IXOCARPA. In North America we often call the fruits "tomatillos" (toh-mah-TEE-yos) or "husk tomatoes." The latter name is appropriate because the fruits look like small, green tomatoes of the regular sort suspended inside a dry, papery bladder. Hanging on the plant the fruits look like Chinese lanterns. Wild Physalises produce smaller fruits suspended in bladders, and you can visualize what purpose the bladders serve. When the husked fruit falls to the ground, wind blows the bladder around like a tumbleweed, helping the seeds disperse into new territory. In the market this week I bought a handful of husk tomatoes to show you. They're at https://www.backyardnature.net/n/07/070512jt.jpg.

Husk tomatoes have been part of indigenous Mexican cuisine for thousands of years, and the last time I was in a US supermarket they were on sale up there, too. The ones up there were nearly the size of regular tomatoes. I think folks here would regard those as too watery and lacking much taste. You can read all about tomatillos or husk tomatoes at http://www.floridata.com/ref/p/phys_ixo.cfm.

The Spanish terms for red tomatoes and husk tomatoes -- which are in the same family but different genera -- can be confusing.

In our part of Mexico the regular, red, huskless tomato is called jitomate (hee-toe-MAH-teh), while husk tomatoes are referred to as tomates (toe-MAH-tehs). However, my Spanish-English dictionary gives only one translation for the English red "tomato," and that's tomate. In the Spanish section my dictionary does list the word jitomate as a special Latin-American Spanish term for "tomato." In fact, in some parts of Mexico they also use tomate for "tomato." So, a red, English tomato is either a jitomate or a tomate, and the husk tomato is either a tomatillo or a tomate, depending on where you are. Several times I've lost my credibility as an effective Spanish-speaker by walking into a market and using the wrong word for tomato.

Of course the words "tomato" and tomate are so similar because "tomato" was derived from the Spanish tomate, which in turn had been taken from the native-Mexican Nahuatl (language of the ancient Aztecs) tomatl -- which was based on the Nahuatl word tomana meaning "to swell." So, tomatoes are "swollen fruits." But who knows whether the Aztecs were talking about red English tomatoes or green husk-tomatoes?

*****

"NIGHT-BLOOMING CEREUS" IN FLOWER
You can see the "Night-blooming Cereus" I'm talking about, growing next to a sidewalk in downtown Japan, at https://www.backyardnature.net/n/07/070512nc.jpg.

"Night-blooming Cereus" is in quotation marks because several cacti go by that name. Ours is HYLOCEREUS UNDATUS. It's native from Mexico to northern South America, but is naturalized in tropical and subtropical zones worldwide. One reason for the plant's popularity is its foot-long, fragrant, beautiful blossoms -- among the largest in the Cactus Family -- but also it's grown for its edible fruits. You even see the species growing wild in southern Florida, though it's unclear whether those plants are persisting vegetatively, or actually reproducing by seeds.

The large, red, fruits, known as strawberry pears or dragon fruits in English, and pitayas in Spanish, are an important crop in some places. In the Yucatan fruits are produced on trellised plants grown in large plantations. You can see a fruit at http://www.tradewindsfruit.com/dragon_fruit.htm.

If you have a "Night-blooming Cereus" that doesn't look like the Hylocereus undatus in my picture, you might compare your plant with the following species, all with huge, white blossoms, and all known as "Night-blooming Cereuses":

Epiphyllum oxypetalum: http://davesgarden.com/pf/showimage/20630/

Peniocereus greggii: http://www.desertmuseum.org/programs/images/Pengre03.jpg  

Selenicereus grandiflorus: http://www.kakteen-piltz.de/pages/010_jpg.htm

*****

LINES OF SEEDS ACROSS THE ROAD
When you walk the gravel road along the reservoir you often cross narrow lines of seeds extending from beneath Lysiloma trees, maybe L. acapulcense, to across the road. You can see such a seed-line at https://www.backyardnature.net/n/07/070512as.jpg.

Lysilomas look like Acacias, but their flat fruit pods, or legumes, bear ribs along both sides, from which the pod faces come loose, allowing the seeds inside to escape. In the picture you can see a Lysiloma pod with one face that has come undone.

Ants left the seeds there. Some ant species are known as seed harvesters, so I figure the lines are their work.

Googling the keywords "seed harvesting ants" I was astonished by how many scientific papers were summoned, more than for any other such topic I've ever queried, I do believe. One reason it's such a favorite for ecologists is that ant seed-harvesting is an important component of many ecosystems, especially arid ones. Mainly, seed harvesting ants disperse seeds, and tunnel in the soil aerating it. There's even a full-fledged word, an adjective, meaning "dispersed by ants." It's MYRMECOCHOROUS. Our Lysiloma seeds are myrmecochorous! "Myrmeco" is Latin for ant.

In fact, I read that species from over eighty plant families have evolved seeds that exude a conspicuous appendage called an elaisome. Elaisomes are nutritious, lipid-rich (fat-rich, therefore caloric) seed appendages that apparently encourage ants to collect them. Many plants clearly "want" their seeds dispersed by ants -- even though the obvious goal of the ants is to eat the seeds and thus destroy them.

However, some seeds get lost along the way -- like those in the photo -- and others are overlooked in the ant nest and may sprout. On the average, ants carry seeds much farther from the parent trees than they'd otherwise travel, so the help in dispersing the seeds into new territory far outweighs the fact that the vast majority of the seeds will be destroyed.

One topic ecologists like to study is how plant communities are altered if ants are killed or kept away.

*****

GREENING SLOPES
The dry season continues here. Many woody plants remain completely leafless but a surprising number are issuing fresh shoots and leaves. The slopes, then, are spotty, mostly still gray and brown, but here and there greenness explodes with springy vigor. You can see this at https://www.backyardnature.net/n/07/070512sm.jpg.

In the photo, the leafless tree with all the brown legumes is one of the Lysilomas from which a line of ant-dropped seeds departs. The gravel road is the one I walk every day along the reservoir.

Lately we've had some hot days. Sometimes the afternoon breeze entering the window next to my desk registers 100° on my shaded thermometer. On the gravel road beside my casita it's often 115. But, as I've said, the air here is so dry it doesn't really feel bad. I don't stay perpetually wet from sweat as I did all those summers hermiting in humid southwest Mississippi.

*****

MYSTERY BUTTERFLIES IDENTIFIED
A couple of Newsletters ago I told you about a dense cluster of butterflies beneath a rock in the mountains near San Juan de los Durán. Some Peace Corps people and I had stopped in a juniper/oak forest to admire the large cycads, and look for herps. You might remember the picture of the volunteer photographing the mass at https://www.backyardnature.net/n/07/070428bu.jpg and a close-up showing two individual butterflies at https://www.backyardnature.net/n/07/070428bv.jpg.

Dr. Tom & Dr. Andy at the University of Florida, and Dr. Roberto at the University of Querétaro, all independently came up with the same name. The butterlies were EUMAEUS CHILDRENAE, of the Gossamer-wing Butterfly Family (Lycaenidae), and the Hairstreak Subfamily (Theclinae). Roberto referred to them as Cycad Butterflies because their caterpillars eat the big cycads we stopped to see. Roberto said that the larvae take in, or sequester, toxins from their cycad host plants, so the adults turn out to be very toxic and just don't need to worry much about predators. The elegant way to refer to this phenomenon is to call it "acquired chemical defense."

Of course this is a similar story to Monarch Butterflies, whose caterpillars eat bitter milkweed, resulting in the Monarchs tasting bitter, and also hang in big clumps. I wonder if the clumping might cause the whole resting group to emit such a dangerous-seeming odor that potential predators know to stay away?

Another English name found for this species is "Superb Cycadian." I like that.

What a pleasure to find and know this wonderful critter.

*****

NATURAL PARADIGMS
More can be said about David W. Orr's remarks profiled in last week's Newsletter. He wrote:

Further:

During this week's livestock-trail walk through robin family aggregations, the above thoughts juggled in my mind until I came up with a reformulation of those ideas: I believe that the loss of our ability to think well about many things derives from our society's loss of contact with Nature.

For, all complex systems, be they the planetary biosphere, free-market economics, the field of geometry, or any other elaborate arrangement, are structured upon certain paradigms. I use the term paradigm in the sense of one of its meanings, which is "a set of assumptions, concepts, values, and practices that constitutes a way of viewing reality for the community that shares them."

For example, free market philosophy is based on the paradigm of supply and demand. Geometry survives on the paradigm of there being a fixed system of relationships among points, lines, angles, surfaces, and solids.

But, free-market societies obsessively focused on financial investment and return fall apart when disenfranchised people make revolution, destroying the production means. Geometry loses its ability to predict relationships among points, lines, angles, surfaces and solids when matter approaches the speed of light. In fact, it seems to me that the paradigms of all complex systems, save one, eventually fail when those systems mature into their pure states.

The one complex system whose paradigms do not fail is Nature. Of all complex, real-world systems in the human experience, only Nature has proven to be truly sustainable, to be based on truly dependable paradigms.

Yet, people choose to harmonize their lives with paradigms other than Nature's. They live according to political theories, religious doctrines, local systems of mores and social practices -- despite history showing that all such systems of belief are ephemeral. They may seem comfortable and expedient for the moment, but eventually they always cause suffering and destruction, if only because they fail to change sufficiently in an always fast-evolving world.

Yet, who is bothering to identify and recognize as sacred Nature's paradigms? A few of Nature's paradigms are so obvious that even I can make them out:

Returning to those Clay-colored thoughts, another way to articulate them is this:

Not experiencing Nature, we remain ignorant of Her paradigms. Lacking Her paradigms, we cannot think well about many things.

*****

Best wishes to all Newsletter subscribers,

Jim