December 20, 2009

GREAT-TAILED GRACKLE
At https://www.backyardnature.net/n/09/091220gr.jpg you see one of the best known, widely distributed, conspicuous, noisy and gregarious birds Mexico has to offer. It's the Great-tailed Grackle, QUISCALUS MEXICANUS. In some towns you hear them screeching and whistling all the time, but at Hacienda Chichen only a few come and go. I'm guessing that they have a base elsewhere, maybe at the ruins or in Pisté, and during the day fan out to places like this. They're not here every day.

These are fair-sized birds. North America's Common Grackle reaches about 12 inches long (30 cm) while Great-tailed Grackles reach 16 inches (41 cm).

I've always had a soft spot for Great-tailed Grackles because I associate their calls with the feeling of escaping the North's coldness and tension. So many times as I bused south from Kentucky for a winter in Mexico, when I changed buses at dawn in San Antonio I'd step outside the station for fresh air and hear them: Sheer shrieking cacophony in the little park a block away. South of San Antonio I'd hear that sound in every town center I'd pass through all through Mexico. Their calls always said to me "Welcome back to heat, color and rambunctiousness!"

Here's the first part of how Howell describes their calling:

"Varied loud shrieks, clacks, whistles, and chatters, including a bright, piercing, ascending whistle, wheeeeu' or s-weeeeerk!, bright piping to shrieking series in various combinations, wee kee-ee-kee-keek or shreeih dee-dee-dee-dee-dee-dee-dee-dee, etc, a burry note.... " It goes on and on. It's the burbly, unzipped sound and mood of the tropics, exactly there.

My old, 1966 field guide to birds calls them Boat- tailed Grackles, but nowadays that name is reserved for a somewhat smaller species along the US Gulf Coast, which earlier was lumped with our Mexican ones. My 1966 field guide shows Great-tails reaching only into southern and western Texas, and southern Arizona. Since 1966 the species has expanded northward and westward dramatically, now occupying the area shown at http://bna.birds.cornell.edu/bna/species/576/galleries/figures/figure-1.

Part of that enormous expansion may be due to global warming but I suspect that mostly it simply reflects this bird's vigor and aggressiveness, and its ability to exploit certain ecological niches that humans create, like parks with trees, fields and weedy wastelands.

*****

A THOUGHT-PROVOKING WASP
The other day an ant-sized wasp came hurrying up my leg carrying something green below her. My eyes are giving way so often I photograph things I can't see well, then later on the laptop screen I examine them, for at least one eye focuses at screen distance. The picture turned out a little out of focus but I it was still clear enough to see what was going on, shown at https://www.backyardnature.net/n/09/091220ic.jpg.

I assume that that's an ichneumon wasp, and she's carrying a spider. Female ichneumon wasps bear swordlike ovipositors at the tips of their rear ends, or abdomens. You can barely see the ovipositor on the wasp in the photo. Probably that wasp is carrying the spider to her nest where with her ovipositor she'll deposit an egg into, on or near the spider's body. When the egg hatches, the larva will eat the spider as it grows.

From what I read, typically the spider or caterpillar -- it depends on the wasp species which -- sealed into the nest with the egg is not dead, just paralyzed with a sting, so that the larva's food will be "fresh" when it needs to eat. You can see that the spider's legs also have been snipped off.

Sometimes you can convince yourself that Nature is overwhelmingly easygoing, magnanimous and forgiving. But if you look at the details you see that most living things experience a very narrow margin of survival in an unsentimental world of eat-and-be- eaten. If you need to cut off a live spider's legs so it'll carry easy and fit into your nest, so be it.

Does this mean that if humanity is to practice living patterns harmonious with Nature's paradigms we must be open to being cruel and unfeeling? No, because humans have access to ideas that can evolve and be passed on, and spiritual insights that sensitize us to beautiful things, such as other forms of life. We may be programmed genetically for brutality, but the mind can set us free from that path.

*****

PIGEONBERRY
Along trails and at woods edges there's lots of the two- to six-ft-high, herbaceous-looking but woody- based plants bearing racemes of white flowers shown at https://www.backyardnature.net/n/09/091220rv.jpg.

If the plant looks like a diminutive pokeweed it's because usually it's assigned to the Pokeweed Family, the Phytolaccaceae, though some put it into the Petiveria Family, the Petiveriaceae, which I've never heard of. In English it's called Pigeonberry, Rouge- Plant, Baby Peppers and other names. It's RIVINA HUMILIS, and the reason it has English names is that it grows in the US Deep South, as well as the West Indies, and Mexico south into South America. It's a delicate-looking plant but clearly a tough one if it can prosper over such a large distribution.

The flowers, only about 1/8th inch long (4 mm), bear looking at. One with its four swoop-backed sepals, four stamens looking like matchsticks with crooked heads, and the ovary with its slender neck, or style, bent to one side before thrusting the pollen-receiving stigma beyond the clustered anthers is shown at https://www.backyardnature.net/n/09/091220rw.jpg.

One wonders why the flower feels the need to bend its style. All Pigeonberry flowers do it, and it seems to be a feature of the whole genus.

As racemes of Pokeweed flowers soon give way to dark purple fruits, Pigeonberry's flowers soon are replaced by glossy, bright red berries, as shown at https://www.backyardnature.net/n/09/091220rx.jpg.

The berries, though very eye-catching with their gaudy redness as you walk along a trail, are small, only about 1/8th inch across (4 mm). Despite one of the plant's names being Baby Peppers, the fruits aren't spicy-hot at all. They taste slightly unpleasant, a little bitter and oily. Birds eat them but not as readily as you'd expect of a fruit so perfectly sized for bird-nibbling and so visible. You see some racemes holding ripe, red fruits for days with no one eating them. Maybe this is explained by a website referring to Pigeonberry as a toxic plant that causes milk taint if cows eat it.

Also I read that juice from the berries once was used as a dye and ink, and that the fruits contain a pigment known as Rivianin or Rivinianin, which is very similar to betanin, the pigment found in beets.

In tropical and subtropical areas Pigeonberry makes a fine groundcover in places too shaded for other plants. In deep shade it simply grows smaller than where it has plenty of sunlight, but it still produces pretty racemes of white flowers followed by crimson berries of questionable edibility.

*****

BUTTER DAISIES
Along roadsides here at the beginning of the dry season a certain yellow-blossomed composite often grows so thickly and blooms so robustly that during most of the day when the sunlight is almost too bright and heavy to deal with, you just have to pause and look at them. Sometimes for miles almost pure stands of them go on and on, reminding a Northerner how in late summer sometimes up there Spanish Needles -- also yellow-flowered composites -- put on similar shows. You can see a sample patch of their inch-wide heads at https://www.backyardnature.net/n/09/091220mp.jpg.

They're Butter Daisies, MELAMPODIUM DIVARICATUM, and like Pigeonberries they have an accepted English name because they live in southern Florida as introduced "weeds." Mainly, however, they're distributed from Mexico and the Caribbean into South America.

Butter Daisy blossoms are unusual, but to appreciate what's special about them you need to know what a "normal" Composite-Family member is like. You can refresh your memory about basic composite anatomy at https://www.backyardnature.net/fl_comps.htm.

First, you can see a single flower head at https://www.backyardnature.net/n/09/091220mq.jpg.

There's not much unusual there. The center is occupied by dozens of crammed-together disk flowers and these are surrounded by petal-like ray flowers. But take a look at what you see when a head is broken open, at https://www.backyardnature.net/n/09/091220mt.jpg.

Notice that the disk flowers in the center have no developing fruits, or achenes, at their bases. That's because Butter Daisy's disk flowers are sterile -- only its ray flowers produce fruits. That's a little unusual among composites, but not very.

But what are those pale green, wedge-shaped things forming a circle just beneath the ray flowers? They are maturing fruits, or achenes, each produced by a single ray flower. A few composite genera have their achenes produced only by ray flowers, but very few of those have wedge-shaped achenes.

There's another unusual thing about flowers in this genus, as shown prettily at https://www.backyardnature.net/n/09/091220mr.jpg.

In "normal" composite flowers the green bracts at the flowerhead's bottom -- the involucral bracts -- are numerous and overlap one another like shingles on a roof. Melampodium bracts are few and ours are fused together at their bases, forming a shallow bowl. You can see the resulting amazing structure at https://www.backyardnature.net/n/09/091220ms.jpg.

In the picture several achenes have fallen out. I suspect that this pie-plate design explains why the individual flower heads stand atop long, slender stems, or peduncles: Atop such limber stems the heads are likely to swing exaggeratedly in the wind or when an animal moves through them, tossing pie-slice achenes from the pan. Everything seems designed to further fruit dispersal.

*****

PEPEROMIAS
Lots of homes up North feature potted peperomias, especially the kinds with attractively crinkled, variegated, succulent leaves. If you've grown them you know that in general they like moist air and can survive in fairly shadowy places.

The other day I was tickled and a little surprised to find a wild peperomia growing in the reserve here. Farther north and west in the Yucatan I've not seen peperomias, for the dry seasons there are just too severe for them. In the Yucatan, the farther northwest you go the drier it gets. Peperomias become common farther south and east of here. I think we must be right at the northwest extreme for them.

At https://www.backyardnature.net/n/09/091220pp.jpg you can see a small part of the plant or colony I found, growing thickly on a tree trunk to about eight feet high. I'm calling this PEPEROMIA PERESKIIFOLIA, a wide-ranging species found from Mexico to northern South America. It's distinguished from similar peperomias found near here by having strong secondary leaf-veins arising from the leaf bases and more or less paralleling the midveins nearly all the way to the leaf tips. Also, most species don't grow in such large clumps.

The long, slender, yellowish thing is the plant's flower spike covered with probably more than a thousand tiny, much-reduced flowers bearing just two stamens each, and a single pistil subtended by a scale. This species' spikes also are exceptionally long and slender compared to those of most other peperomia species.

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POTHOS VINE
Maybe at Hacienda Chichen the ornamental plant most asked about by visitors is the Pothos, EPIPREMNIUM AUREUM. It's closely related to the Philodendrons, thus a member of the Aroid Family, the Araceae. You can see one wrapping itself around a Royal Palm trunk at https://www.backyardnature.net/n/09/091220po.jpg.

Pothos, native to Southeastern Asia, impresses people with its sheer robustness, climbing up trunks 65 feet (20 m) and producing broad, glossy, yard-long (meter-long) leaves on shovel-handle-thick stems using aerial roots to climb. You can see stems and petioles at https://www.backyardnature.net/n/09/091220pn.jpg.

Pothos does something interesting: When it grows tall it starts sending down leafy stems a little like the things Tarzan swings on in the movies. When the stems reach ground they root and start wandering on the ground horizontally, and can eventually form a very attractive, closed groundcover. The wandering stems bear leaves much smaller than those on climbing stems. If you whack off a stem section and pot it, you'll get a very attractive plant of manageable size. You can see the base of a tree trunk overgrown with Pothos, with large leaves above and small ones on the ground, at https://www.backyardnature.net/n/09/091220pm.jpg.

Noticing the leaves' yellow streaks, you may think you recognize Pothos as a potted plant in your own home or at least in your hometown shopping mall lobby, and you're probably right. Pothos is one of the North's most common houseplants. On the one hand, studies show that Pothos removes indoor pollutants such as formaldehyde, xylene, and benzene; on the other hand, the plant may be toxic to dogs and cats due to insoluble calcium oxalates in its herbage.

You might notice that the big high leaves in the first picture had many splits in their blades while the last two pictures showed leaves with few to no splits. Basically young, lower leaves tend to be splitless while higher or older leaves have lots of splits.

*****

HELICONIAS
Heliconias are among the most exotic-looking plants we have here. You can see a portrait of one at https://www.backyardnature.net/n/09/091220hc.jpg.

Heliconias, as you might guess from the broad leaf behind the flowering structure, is a member of the Banana Family. They're such gorgeous and unusual plants that many cultivars have been created and many hybrids made, so often it's hard or impossible to assign a species name to a plant. However, ours look very much like HELICONIA LATISPATHA which grows wild farther south and east of here where there's more rainfall, so that's what I'm guessing it is.

The orange structures aren't flowers, but rather boat- shaped modified leaves, or bracts, where earlier flowers arose "in the back of the boat" where the bracts attach to the zigzagging stem. Those black, shiny things are fruits, the flower period having long passed. A close-up showing the berry-like fruits is at https://www.backyardnature.net/n/09/091220hd.jpg.

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CHICKEN-BONE STORY
Some folks never write unless it's to pick a fight or point out an error, so I was tickled the other day when David in Bermuda, who in the past has written only to contend bird IDs, sent a letter. He's too nice a guy to pick a fight and I knew that the bird in last week's Newsletter was properly identified, so here was a letter just to keep in touch.

Wrong. He was addressing the iguana skull in last week's Newsletter:

"Your 'skull' is, in fact, the fused backbone and pelvis that characterises all birds. The apparent 'eye holes' are where the femurs attach. I can't identify your bird synsacrum but I will venture to guess it is from a chicken, possibly now the most abundant bird on the planet. I guess this confirms you as a vegetarian because otherwise I am sure you would have recognized it from any half eaten roasted chicken!"

During this last week I've come to terms with my embarrassment, but the incident has lingered in the form of philosophizing on the subject of "enduring false concepts."

The week before, I'd felt dumb for having needed a Maya friend to identify the structure a an iguana skull. Once the iguana was mentioned, whenever I looked at the "skull" on my table the unmistakable features of an iguana face just jumped out, especially when viewed from the perspective shown at https://www.backyardnature.net/n/09/091220~~.jpg.

Don't you clearly "see" the iguana's broad head with crests over the eyes, the eyes themselves and the narrow nose bridge? But, I checked: It's really a bird's "synsacrum," as David would say.

The incident wouldn't have been so poignant had not I just returned from a hike to Pisté to buy bananas and oranges. It was December 12th, Virgin of Guadalupe Day, and that day I shared the roadside with dozens of runners carrying flaming or at least smoking Olympic- type torches, preceded by pickup trucks with blinking lights and sirens, and carrying large, colorful images of The Virgin. I was told that many of the runners during the last year had promised The Virgin that if She would intervene in some way for them they'd run a certain distance, and December 12th was pay-back day. Some people were running barefoot on the hot asphalt littered with shattered glass.

During that walk I reflected on how people in general can believe almost anything, WANT to believe something, and how beliefs get tangled up with national pride, family and community solidarity, the need for rituals, etc. And then along came David's letter pointing to my own illusions.

We've touched before on how our brains are split into two hemispheres, the left hemisphere being super logical while the right deals with feelings, symbols, etc. The right hemisphere is always coming up with "stories" to explain things. It not a subtle thing, either. The right brain relentlessly spews out stories, real and imagined, whether we want them or not. If you don't believe it just try to "empty" your brain, and note how very quickly some kind of story gets your attention, maybe something someone said, or something you should have said, or could have said...

In the struggle to save Life on Earth, in many ways it's an effort to not let the story-telling right hemisphere overwhelm the fact-dealing left hemisphere. But, it's hard, so hard. You saw what a nice story it made last week when my uneducated friend had to tell me which animal the "skull" was from. I liked believing that story; it fit in with lots of my other favorite stories.

But, there's a problem with yielding uncritically to beguiling stories. For instance, the other day a Northerner came through characterizing the Global Warming debate as nothing but Socialist propaganda designed to further the redistribution of wealth from the rich countries who worked for it to the poor ones who didn't.

It's a good story, and it meshes nicely with a world of other stories like it, but, while my chicken-bone story just makes me look foolish, stories like the global-warming one can kill us all.

As usual, my best suggestion for what looks like a hopeless situation is to focus on Nature, to let Nature speak to each of us, one at a time. Let Her impart to us Her sustainable paradigms, or models, as we study flower structure, or butterflies, or ecology... or bird anatomy.

Lordy, what a lot of grief a little bird anatomy can save you!

*****

Best wishes to all Newsletter readers,

Jim