December 3, 2007

WOODCREEPERS
If you're looking hard for birds, often you don't see woodcreepers. Woodcreepers appear once you're tired out, just gazing blankly into the forest hoping something will flit before you. Then they're like brown leaves the wind silently blows from a shadowy place higher up to a shadowy tree trunk lower down. Woodcreepers aren't flamboyant birds at all. They're like bespectacled, gray-haired clerks in dark, dusty offices in a Dickens novel, just working, working, working at their modest job of gleaning invertebrates from tree-bark fissures, from beneath lichen flecks, from little holes a normal bird might overlook.

No-nonsense Woodcreepers belong to their own family, the Woodcreeper Family, the Dendrocolaptidae, which isn't represented at all in North America or the Old World. It's a strictly neotropical family. Mexico hosts 13 woodcreeper species and they're all reddish-brown birds who climb tree trunks like woodpeckers. Though they're shaped very much like North America's Brown Creepers, Brown Creepers are in an entirely different family. This is a fine example of convergent evolution at work, clear evidence that Nature thinks that a bird who gleans tiny invertebrates from tree trunks ought to be brown and have a certain low-slung shape, and a certain behavior, no matter which family it belongs to.

My list of birds potentially to be seen in upland Chiapas at https://www.backyardnature.net/chiapas/birds-ch.htm lists nine woodcreeper species. Four woodcreeper species have been identified here at Yerba Buena. You can see one of those, the Spotted Woodcreeper, at http://avesphoto.com/WEBSITE/PA/gallery/Gall-8.htm.

In that picture the similarities between North America's Brown Creeper and one of our tropical woodcreepers are obvious. A big difference between them, hard to judge in the photo, is that Brown Creepers are 4.75 inches long while Spotted Woodcreepers are up to 9.5 inches long. Mexico's largest woodcreeper is 12.2 inches long. Our smallest species is only 5.8 inches long, which approaches Brown Creeper size, and from a distance really looks and behaves like a Brown Creeper.

Woodcreepers can be hard to identify. The main differences between them are based on whitish streaking and spotting on their brownish bodies. Usually you must have a good view before you can decide whether the back is really unstreaked, or maybe you're just not seeing the streaks, and the same goes with spotted or not- spotted chests. Once you're familiar with a species you can often recognize it by its voice because woodcreeper voices are fairly distinctive. Howell describes the Spotted Woodcreeper's voice as "A plaintive, descending and slowing series of 2-4... rich, slurred whistles, wheeeoo,    wheeeoo,         wheeeoo                wheeoo..."

The distributions of most of Mexico's woodcreepers continue from here through the tropics at least to Panama and often clear to Argentina. Therefore, once you learn ours you're ready for them when you hit Costa Rica or even the Amazon.

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NO NUTHATCHES, TITMICE OR CHICKADEES IN CHIAPAS
North American birders often think of nuthatches, titmice, chickadees and Brown Creepers as similarly small, curious, conspicuous birds that often flock together, especially in the winter woods. Here, despite our high-elevation, semideciduous forests sharing so many species with eastern North America's forests, that cheerful bird-assemblage just doesn't exist.

Supposedly North America's Brown Creepers do indeed occupy the Chiapas highlands, but I've not seen them. They occur in upland forests as far south as Nicaragua.

However, nuthatches, titmice and chickadees aren't represented at all in Chiapas. Among the nuthatches both White-breasted and Pygmy Nuthatches follow the cool uplands from the US border deep into south-central Mexico, but they don't make it across the lowland Isthmus of Tehuantepec to here.

Similarly, Mexican and Mountain Chickadees, as well as Bridled, Plain and Black-crested Titmice all extend across the US border into Mexico, but none has made the leap across the lowland Isthmus of Tehuantepec.

I've wondered why this might be so. Maybe it's because when North America's migrants overwinter here they fairly saturate the ecological niche for birds foraging on small, arboreal invertebrates. Remember that North America's winter coincides with our dry season, and the dry season is our least buggy time of year. Maybe, at least during the dry season, there's just not enough bugs to go around for both winter visitors and permanent-resident nuthatches, titmice and chickadees.

Or maybe the Isthmus of Tehuantepec's lowlands have been just too extensive, hot and humid for upland- loving nuthatches, titmice and chickadees to make it across.

Whatever the reason, the lack of those birds in our chilly forests with abundant Sweetgums and Blackgums feels as strange as it does seeing bromeliads and orchids growing on North American tree species here in Mexico's southernmost state.

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I HAVE ANOTHER DIGITAL CAMERA
Before I could buy a new one, Ivonne in Mexico City has given me a dandy little used digital camera, so now the Newsletter can continue having pictures. I got the camera going yesterday, Sunday, so you can see its first pictures. I accompanied some folks to Coapilla, a pretty, very isolated town on the slope between here and the Gulf Coast lowlands, to visit a commercial blackberry-growing farm. You can see a little boy, very nervous about holding a blackberry setting just right, at https://www.backyardnature.net/n/07/071203bb.jpg.

This was my first time on the slope since the floods that devastated Villahermosa (water reached the tops of the buses at the first-class ADO bus station) and was appalled at the number of landslides on the largely deforested slopes. You can see a slide with a car on it at https://www.backyardnature.net/n/07/071203sn.jpg.

The remainder of my shots in this Newsletter are stored pictures from the old camera.

Again, thanks to Ivonne for helping keep this Newsletter illustrated.

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THE MELASTOMA FAMILY
You can see one of my old images, that of a common, almost weedy herb currently flowering rather prettily now, at https://www.backyardnature.net/n/07/071203ml.jpg.

If you travel in the humid tropics and like to know what plants you're seeing, you need to know the family to which this species belongs. That's because, unlike the vast majority of plant families, this family is easy to identify, even without flowers or fruits, plus its member species are very commonly encountered, occurring in every moist habitat from weedy roadsides to old-growth rainforests.

It's the Melastoma Family, the Melastomaceae, embracing about 175 genera and 3000 species worldwide. Though it's predominantly a tropical family, at least one genus, Rhexia, is represented among North American wildflowers. Species of the genus Rhexia are often referred to as Meadow-beauties. If you have a wildflower book you might look it up to confirm whether Rhexias show the features mentioned below.

The plant parts making plants in the Melastoma Family to be so easy to identify are the leaves. Leaves arise opposite one another, they're shaped like those in the picture and, most distinctively, they possess three to nine conspicuous "nerves" extending from where the petiole attaches to the blade to the blade's tip. The nerves are like midribs. You can see that the leaves on the plant in my picture are 3-nerved, or maybe there are other nerves very near the margins, making them 5-nerved.

Also, notice how secondary veins connect the primary veins, spaced like rungs on a ladder. All members of the Melastoma Family I've ever seen display this unusual vein pattern, and it's wonderful when you're in the humid tropics wanting to know what you're seeing and can't identify a single plant except maybe some orchids and bromeliads on tree limbs. If you see an herb or bush with those characteristic veins, you have a member of the Melastoma Family.

You may recognize that the flowers in the picture are somewhat similar to those in the Evening Primrose family -- especially because of those conspicuous, yellow stamens of irregular shapes and sizes. In fact, the Evening Primrose and Melastoma Families appear very close to one another on the evolutionary Tree of Life. In a way, the Evening Primroses are the Temperate Zone's counterpart to the mostly tropical Melastomas.

Being able to identify something just to its family often is a big help. For instance, the only Melastoma- Family member identified by the 1986 University of East Anglia expedition to Yerba Buena was Miconia mexicana, so if I had access to the Internet right now I'd browse for a picture of Miconia mexicana and see if it matches the unknown Melastoma-Family member in the above picture.

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AFRICAN TULIP TREES FLOWERING
All through the tropics right now, especially in parks and along streets, there's a tree with dark green leaves and large, red blossoms so showy that, even in a land of many gorgeously flowering trees, your eyes gladden just to see it. You can behold one of ours at https://www.backyardnature.net/n/07/071203sq.jpg.

That's the African Tulip Tree, SPATHODEA CAMPANULATA, and it's really from Africa, but planted worldwide in the tropics because of its beauty. Of course having a worldwide distribution it's known by many names. Another English name is Santo Domingo Mahogany, though it's not related to real Mahogany at all, being in a completely different family, the Bignonia Family. In Spanish sometimes it's called "Flor de Fuente," or "Fountain Flower," because the four-inch-long blossoms curve into a cup that can hold water for visiting birds and insects. You can see a blossom in my hand at https://www.backyardnature.net/n/07/071203sp.jpg.

Besides its beauty, the tree is often planted because it's fast-growing and can be reproduced from seeds, root suckers or cuttings. One problem with the tree is that its branches are brittle, thus very susceptible to wind injury.

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UNKNOWN ORCHIDS
Among the most interesting members of our landscape are the orchids. Worldwide, the Orchid Family is the most species-rich of all plant families, and the variety and diversity within it is practically overwhelming. Breedlove's Flora of Chiapas list 450 orchid species just for Chiapas. Unfortunately I have no key or field guide to any plants here so when I find an orchid there's not much I can say or do about it, other than to observe that it sure is pretty.

The 1986 University of East Anglia expedition here identified the following orchid species at Yerba Buena:

Undoubtedly this is just a small portion of our resident orchid species.

Blossoms of two orchids flowering at Yerba Bueno nowadays can be seen at https://www.backyardnature.net/n/07/071203o5.jpg and https://www.backyardnature.net/n/07/071203o6.jpg.

Both of these species are terrestrial. The first produces a cluster of long blades rising from the ground like a lily, and lives in moist, shady woods. The second produces leaves on long stems that range over roadside weeds, for the plant is actually weedlike itself, growing along the highway.

I don't know if my two illustrated orchids are among the species listed for Yerba Buena above. Having to use cibers in town I'm unable to spend the time I'd like browsing for pictures matching my finds. If someone is up to the challenge, you are most welcome to try to identify my pictured unknowns. Let me know if you figure them out. I can be emailed via the page at https://www.backyardnature.net/j/writejim.htm.

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CHIAPAS'S DOZEN VEGETATION ZONES
Experts divide Chiapas's vegetation into various zones with various names. In terms of gross community- structure and physiography, most schemes recognize about a dozen zones. The following English names are those I feel comfortable with, accompanied by Spanish names often used for them:

To see a map of these vegetation zones and lists of species characteristic for each, go to https://www.backyardnature.net/chiapas/veg-map.htm.

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ON TURNING SIXTY
Last month I turned 60 years old, so I've been thinking about what I've learned during all those years.

I've seen too many foolish, self-deluding old people to believe that age automatically imparts wisdom. I've also seen how my own perceptions shift depending on what my blood pressure and blood sugar level happen to be, as made clear in my essays "Pickle Juice," online at https://www.backyardnature.net/j/o/pickjuic.htm and "Hypoglycemia & Spiders," at the bottom of the page at https://www.backyardnature.net/n/01/010909.htm. Therefore, who knows if what seem like profound insights to me actually may be nothing more than illusions peculiar to my own ephemeral state of mind?

Still, if someone should ask me what has been the most important insight I've developed so far in life, I'd not hesitate to say this:

If we need guidance on how to conduct our daily lives, and how to think about the world in general, the "Nature Bible" is the most appropriate guide.

And, why shouldn't the way that Nature is constructed and behaves offer profound insights? Nature is nothing less than the way the Universal Creative Force expresses Herself. The Universal Creative Force is a musician and all things on Earth and beyond are Her music. It would be surprising if a piece of music didn't reveal something about the character and maybe even the intentions of the composer.

Here are some of the most important teachings of the Nature Bible I've found, clearly revealed in the Book of Evolution:

Someday when Nature's most obvious and elemental teachings, such as the three listed above, are accepted and honored by most people, a vast body of systematic thought and literature will arise. Discussions based on Nature's teachings will progress in a manner similar to using geometry's theorems to come to conclusions about life in general that aren't immediately apparent. For example, one of Nature's "theorems" is that diversity is sacred; therefore extinctions of living things are to be avoided; therefore we should not destroy habitats with unique species; therefore... etc.

The main proof I have that the above concept may be worth thinking about is this: When one incorporates into everyday life such teachings as the above three elemental "Nature theorems" by, for example, spending a lot of time in the most diverse of all systems, Nature Herself; when one limits his or her use of resources by simplifying the life being lived and consciously controlling one's cravings, and; when one insists on having enough personal space for enjoying peace of mind and letting thoughts mature... that person, in my experience, feels happy.

Long-term "happiness" is part of a positive feedback system Nature uses to encourage Her sentient beings to live in ways that are sustainable for Life on Earth.

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Best wishes to all Newsletter subscribers,

Jim