January 30, 2011

BLUE GROSBEAK OSCILLATIONS
As the dry season intensifies the little birdbath in front of the hut becomes ever more popular. Mostly my visitors are Indigo Buntings, Blue Buntings and Painted Buntings, all a shade over five inches long (13cm). The other day a new blue, thick-beaked bird descended among them, but this one was near seven inches long (17cm) and looked like a St. Bernhard among a pack of street-dogs. In the field you don't notice such a size difference but when they're all in a birdbath together it's striking.

It was a Blue Grosbeak, recognized not only by its larger size but also by its conspicuous brown wingbars. The species is spending its winter here, biding its time until returning up North to nest in approximately the US's southern half. It's shown at https://www.backyardnature.net/n/11/110130gb.jpg.

Even more eye-catching than this bird's size, however, was the strange wavy pattern covering much of his body. At first I thought the oscillations were caused by reflections off the water's wavy surface, but a closer look showed that the pattern resulted from individual blue feathers having pale or brownish tips. Howell in his wonderful A Guide to the Birds of Mexico and Northern Central America makes clear what's happening when he describes the adult male's overall blue plumage as "extensively tipped brown in fresh basic."

"Basic" used by an ornithologist talking about feathers refers to the plumage of a bird during the winter or non-breeding season. Many birders up North even if they're very familiar with Blue Grosbeaks may never have seen this interesting effect.

Blue Grosbeaks winter from Mexico south to Costa Rica.

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MALE SUMMER TANAGER
Summer Tanagers, present in most US southern states during the summer, are common winter residents here. Saturday a bright male landed in the birdbath next to a molting male Indigo Bunting. The tanager carried a grub in his beak and his wing appeared to have lost a few feathers, and some fluffy down feathers showed up as a white splotch on his side, as if an attack had pulled them out of place. This bird seemed to have a story to tell, but all I knew for sure was that he wanted to take a bath after swallowing his grub. He's at https://www.backyardnature.net/n/11/110130tg.jpg.

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FIG BANQUET
Exactly in front of the Hacienda's entrance stand some large, densely leaved, picturesque trees inside which these days there's a continual hubbub of branch-shaking, chirping birds overindulging in figs. The trees are just loaded with soft, juicy figs perfectly sized for a bird's mouth, but without any sweetness or flavor to attract a human. You can see a branch showing how thickly figs grow on it, and how bird poop so generally splatters the leaves, at https://www.backyardnature.net/n/11/110130fg.jpg.

You can see that in this species' semi-mature figs are pale orange while mature ones are nearly black.

The fig trees themselves are "strangler figs," as seen at https://www.backyardnature.net/n/11/110130fh.jpg.

We've already dealt with the wonders of stranglers at https://www.backyardnature.net/yucatan/stranglr.htm.

But, identifying a tree as a strangler fig isn't saying much. Eight fig species -- eight members of the genus Ficus and mostly stranglers-- are listed for the adjacent state of Quintana Roo, and I suppose Yucatán state is home to about the same number. However, our big stranglers are none of those.

A naturalist leading a birding group passed through the other day calling the trees Ficus benjamina, which are big stranglers planted throughout the world's tropics and possibly the most planted of all trees in pots of big Northern hotels and malls. However, the leaves of that famous fig gradually end in long, slender points and display over 30 veins along each side of the midribs, while our fig's leaves end with short, rounded tips and have only ten or so prominent veins along each side of their midribs, as shown at https://www.backyardnature.net/n/11/110130fj.jpg.

Our bird-pleasing strangler fig turns out to be what's sometimes called the Chinese Banyan. It's FICUS MICROCARPA, in old books referred to as F. retusa. Like F. benjamina, Chinese Banyan is from the southern Asia, northern Australia region, and also widely planted in the tropics worldwide. It's much utilized as a bonsai subject.

You probably know that fig trees can't produce viable seeds unless a particular species of wasp that has coevolved with the fig is available for pollination. The wasp enters the fig through a hole at its tip, then walks around atop the many tiny fig flowers lining the fig's walls and pointing inward toward the empty space in the fig's center. You can see the cross section of a fig from one of our Chinese Banyans showing the empty space and matured fruits inside the fig at https://www.backyardnature.net/n/11/110130fi.jpg.

Well, if our figs appear to be full of seeds, then the appropriate wasp pollinator must also be present. That's true. In fact, Chinese Banyans are escaping from cultivation throughout the world's tropics as in one place after another the wasp also is turning up, and then the tree's fertile seeds get spread by birds and bats. Reproducing Chinese Banyans have even gone wild in Florida. The tree's wasp pollinator was first noticed in Mexico around 1985.

Despite my general antipathy toward invasive organisms, when our big Chinese Banyans are exploding with birds eating figs inside them and the asphalt driveway beneath them is splattered and messy with squashed figs and bird droppings full of fig seeds, and mixed flocks of fifty or more Indigo, Blue and Painted Buntings contentedly feed below them, I can't help but feel a bit kindly toward the invaders.

However, I still worry about this invasive's effect on the local ecology. Does its attracting all those feeding birds mean that other local plants needing their seeds disseminated will suffer? Bird poop is generally pasty and lumpy, but the seed-rich poop splattered on the Chinese Banyans' leaves is runny. Are birds eating these figs getting nutritionally balanced meals, or are they feeding on the equivalent of junk food? Our local birds and these Chinese Banyans didn't co-evolve.

You just never know what far-reaching effects any invasive species introduces into a preexisting ecosystem. These Chinese Banyans, however, make a good first impression.

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ARRABIDAEA VINE
This week's star find was a vine with leg-long, spectacularly dangling cascades of tubular, 1-2/3-inch-long (4.2cm), purple corollas, as shown at https://www.backyardnature.net/n/11/110130ab.jpg.

The flowers show up particularly brightly because now during the dry season the vine is mostly leafless. You can see a flower, its lower petal thrust forward a little more than the others to provide pollinators with a nice landing pad, at https://www.backyardnature.net/n/11/110130ac.jpg.

Inside the corolla tube four stamens curve upward to hold yellow anther against the ceiling, so that entering pollinators have pollen dusted from the anthers onto their backs. The white, slender, stiff style projects beyond the stamens so it can receive pollen from the visiting pollinator before it becomes dusted with the flower's own pollen. A longitudinal section of a flower showing all this is shown at https://www.backyardnature.net/n/11/110130ad.jpg.

A very few compound leaves had freshly emerged bearing two or three leaflets, as shown at https://www.backyardnature.net/n/11/110130af.jpg.

Those features are very typical of flowers and leaves of the Bignonia Family. One unusual field mark for this species, however, is its warty calyx, shown at https://www.backyardnature.net/n/11/110130ae.jpg.

This is ARRABIDAEA PODOPOGON, apparently with no English name, since it's endemic to the Yucatan and northern Belize, and not too common. It's such an attractive plant that it deserves to be widely cultivated, though.

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VINES ARE IMPORTANT
Though no attempt is being made to be thorough as we tiptoe through the Yucatán flora and fauna, it's sort of surprising that with the above Arrabidaea now we've meditated on 38 species of herbaceous and woody vines just here in the Yucatán. They're all indexed at https://www.backyardnature.net/yucatan/yuc-vine.htm.

It's true that the central Yucatán's scrubby forest normally is so abundantly populated with vines dangling from overhead branches that normally you just don't want to walk through the woods unless a trail has been cleared.

Some folks here believe that if they clear vines from beneath a tree they're doing the local ecosystem a big favor by "letting in the light, giving things room to grow."

The first problem with that thinking is that, as we've clearly seen with our look at the Yucatán vines, these vines are worthy beings themselves. Not only do they provide nectar for pollinators, but also their fallen leaves add organic matter to the soil, and their roots loosen the soil. Also, most woody species are natives, and for centuries have been used by the Maya in basketry.

Maybe the main problem in removing vines from the forest, however, is because of the damage it does to forest ecology. Not only does it diminish ecosystem diversity, thereby making it less stable by loss of redundant systems, but also during the long dry season the forest's main goal is to survive until the rainy season returns so things can start growing again. When the forest is "cleared out" by removing vines, dry air and desiccating sunlight are admitted, tremendously aggravating the forest's water deficit.

When a regenerating forest like ours is choked with vines, that's a good sign that it's healing, not a sign that it needs human help by being "cleaned out."

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CHAKMOLCHÉ'S ELEGANT RED PYRAMIDS
The dry season becomes ever drier, more and more herbs die back and more and more trees lose their leaves. Deep in a forest with so many leafless trees that it looked wintry to a Northerner's eyes, despite the heavy, scorching heat, a Cinnamon Hummingbird's wing- whir drew my attention skyward, where among a jumble of slender, naked branches I saw what's shown at https://www.backyardnature.net/n/11/110130ey.jpg.

That's the terminal raceme, or flower cluster, of the small tree the Maya call Chakmolché. It's ERYTHRINA STANDLEYANA, endemic to the Yucatan Peninsula and part of Belize. We've seen the genus Erythrina before, when we met a Coral Tree planted in Querétaro (see it at https://www.backyardnature.net/q/erythrin.htm).

But that species bore leaves and its red flowers weren't as slender and gracefully arrayed as these. It created an altogether different effect from the present tree, which bore not just one scarlet raceme but several.

You can imagine what effect this beautiful and somehow magical-seeming display had on the ancient Maya, their minds already suspended in a universe of spiritual beliefs in which snakes spoke, enemies conquered with evil eyes, and only the shamans knew how to help you survive. In fact, Chakmolché is well known by the Maya.

Seeds, bark and stems of the various Mexican species of Erythrina contain compounds that paralyze the motor system. They're so poisonous that in some cultures they're used to stupefy fish to make them easier to catch, and to poison animals. They've been employed as a hypnotic agent. In various places in Mexico the roots have been used when sweating out poisons is required -- they're "sudorific." The leaves supposedly promote menstrual discharge and a decoction of the flowers is used for chest problems. The juice of the stems is applied to scorpion stings. Also the seeds themselves are supposed to protect from "evil winds."

Chakmolché is a member of the Bean Family, and its slender flowers are papilionaceous like so many other flowers in that family -- each blossom bearing a top "banner" petal, two side "wings," and two petals below fused along their common margin forming a scoop-shaped "keel." However, Chakmolché's flowers are so slender that you have to break them apart before you can recognize the five special petals.

Our Chakmolché's fruits and seeds had long vanished, but about ten feet up, one side of an old, empty seed pod, or legume, was wedged in a branch's fork. It's worth looking at, for its shape showing such narrow constrictions between the parts that once held seeds, or beans, helps clinch the tree's identification. See it at https://www.backyardnature.net/n/11/110130ez.jpg.

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CUBAN OREGANO
Back in October we looked at Mexican Oregano, reviewed at https://www.backyardnature.net/yucatan/oregano.htm.

Right beside our Mexican Oregano there's what's shown at https://www.backyardnature.net/n/11/110130og.jpg.

That's Cuban Oregano and unlike Mexican Oregano, which is a much-branched shrub up to six-ft-high (1.8m), Mexican Oregano is a scrambling perennial with stems too soft to call woody and too hard to call herbaceous. Its semi-succulent, crisp leaves are shown at https://www.backyardnature.net/n/11/110130oh.jpg.

Northerners are familiar with a delicate little herbaceous mint known as Oregano, Origanum vulgare, originally from Europe. Mexican Oregano, native to Mexico, instead of belonging to the Mint Family, was a Lippia, in the Verbena Family. The present Cuban Oregano is a member of the Mint Family like "real Oregano," but belongs to a completely different genus. It's PLECTRANTHUS AMBOINICUS, originally from southern and eastern Africa.

I can't tell the difference between tastes of the leaves of "regular Oregano," Mexican and Cuban Oregano. In the Hacienda's famous kitchen, both the latter are used whenever the Oregano taste is called for, and the culinary results are splendid.

English names for the various oreganos are very confusing and misleading. Among Mexican Oregano's other English names were Scented Lippia, Scented Matgrass and Redbrush Lippia. Our present Cuban Oregano seems to have even more names, including Spanish Thyme, Indian Borage, Mexican Mint, French Thyme, Soup Mint, Indian Mint and Country Borage. One reason for the proliferation of names is that Cuban Oregano is very widely cultivated and naturalized in the Old and New World Tropics, so many cultures have come up with many names.

In fact, if you use the Google Image search feature on the keywords PLECTRANTHUS AMBOINICUS you'll see cultivar forms with variegated and/or frilly leaf margins, and blossoms in various purple-tending shades. Our flower's hue is a little different from most, so maybe this is a cultivar the Maya have been working on, through selective breeding, for the 500 years since the Spanish Conquest.

Cuban Oregano's flowers are classic mint flowers, seen at https://www.backyardnature.net/n/11/110130oi.jpg.

By "classic mint" is meant that the flowers are bilaterally symmetrical instead of radially, with four or two stamens, and that the ovary and is composed of four distinctly separated parts.

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DEW
At dawn on most mornings the laundry-dryer-size clump of Lemon Grass next to the hut is wet with dew. When I'm sitting as the sun rises in the east, dewdrops sparkle very prettily. Hardly any view could seem more fresh and bright. Though I knew no picture could ever capture the feeling such a view conveys, mostly because you lose the scene's three-dimensionality, one morning I took a picture anyway, knowing you've seen similar things, and might enjoy being reminded of them. My chilly, sparkling, dew-wet Lemon Grass is at https://www.backyardnature.net/n/11/110130dw.jpg.

Warm air holds more water vapor than the same volume of cold air. Therefore, as warm, moist air cools, a certain point is reached at which it is 100% saturated with humidity -- its dew point.

In the night, my Lemon Grass loses energy by radiating infrared radiation, thus cooling off. When the night's warmer, humid air moves around its blades, air right next to the Lemon Grass's blades is cooled by the blades, cooled to their dew point, where it must dump its water as it continues to cool. The dumped water coalesces on the blades as dew.

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PERCENTAGES
Lately we've been looking at natural paradigms that can provide us with guidance and inspiration in our lives. Here's another:

Over 60% of human genes are basically the same as those found in fruit flies. About 90% of human genes correlate at some level to those of mice. Each human even carries genetic information that could give us a tail, like that of the ancestor we have in common with mice, if those genes weren't "switched off." About 98% of human genes also are found in Chimpanzees. The genes of an Australian Aborigine and a blond Norwegian are at least 99.9% identical.

Our genes are collections of information detailing how to put us living things together. Seeing how throughout the history of Life on Earth this single library of genetic information has been diligently enlarged, reproduced, edited, refined and proliferated -- even as 99.99% of all species that ever existed went extinct -- one realizes that to the Universal Creative Impulse, nothing is more important in the Earthly context than this evolving library.

At least to me, this means that the evolving library is sacred. As such, I feel reverence for the lives of other creatures also carrying the library, especially those with whom I share the most genes. In fact, I would resist killing and eating a Chimpanzee with at least 98% of the vigor I would resist killing and eating a human, and for the same reasons.

Each of us defines his or her degree of reverence for life by deciding where to draw the line on what other living beings we're willing to kill or have killed for us, so that we can eat them.

Another teaching of the current paradigm arises when we see how Nature works with Her sacred evolving library. She began small and simple but gradually expanded and evolved until something grand has been achieved. The gradual expansion and evolution of any complex system amounts to a blossoming.

Discovering ourselves to be part of the continuing blossoming of the most gorgeous and majestic of all things -- the Universe itself -- we find ourselves being taught by this natural paradigm that we have a place as necessary and secure as each of a blossom's petals.

And we see that we also are beautiful, and as worthy as any blossoming flower.

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Best wishes to all Newsletter readers,

Jim