JIM CONRAD'S
NATURALIST NEWSLETTER
Written at Mayan Beach Garden Inn 20 km north of Mahahual
on the Yucatán Peninsula's eastern coast just north of the
Belize border, in the state of
Quintana Roo, MÉXICO

January 5,  2009

SQUEALING BLACK HAWK
A Common Black Hawk, BUTEOGALLUS ANTHRACINUS, has soared past the hotel two or three times since I've been here but it never tarried for a picture. Last Tuesday morning one landed on a dead snag at the edge of the mangroves and showed no interest in flying as I approached to about 20 feet. The shot is at http://www.backyardnature.net/n/09/090105bh.jpg.

He perched on his snag a solid half hour, several times issuing a sharp squeal sounding like a squeaky toy squeezed rapidly for about five seconds, reaching a crescendo of loudness in the middle.

Common Black Hawks are a bit smaller than Red-tailed Hawks, with wingspreads averaging about 46 inches compared to the Red-tailed's ±50. Another similar, broad-winged, yellow-legged black hawk in the same genus occurs here, the Great Black Hawk. In this area when you see a black hawk you just need to keep in mind that the Great wears white speckles on his upper legs but the Common doesn't.

Common Black Hawks occur throughout Mexico's non-desert lowlands, especially near mangroves, and extend southward into northern South America.

*****

LOLLING RUDDY TURNSTONES
I've already told you about our Ruddy Turnstones but the other day I got a new picture of them, shown at http://www.backyardnature.net/n/09/090105ts.jpg.

I like this picture because it hints at what it must feel like being a Ruddy Turnstone out there on a shoal at low tide, plenty of food down in the Turtlegrass, late-afternoon sunlight warming your back as a hard wind blows in off the Gulf, and you have nothing to do but digest and hang out with friends. The birds are atop a car-sized Turtlegrass shoal just up the beach from the hotel.

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WHITE HERONS & EGRETS
You see lots of white herons and egrets here but you always need to look closely to figure out which species you're seeing.

Most sightings turn out to be Cattle Egrets, BUBULCUS IBIS, often seen on the sand road around water puddles stabbing at crabs and other critters. You can see one at http://www.backyardnature.net/n/09/090105ce.jpg.

Breeding Cattle Egrets show conspicuous tawny-buff patches on their crown, chest and back, but you can see that the one in the picture is pure white. Other all-white herons and egrets showing up here are the Great Egret, Snowy Egret, immature Little Blue Heron, and "white morphs" of the Reddish Egret and Great Blue Heron. You have to remember certain features of each to separate them.

For example, Snowy Egrets have yellow feet and immature Little Blue Herons have blue-gray beaks with dark tips, all unlike our Cattle Egret. The main features indicating that what's in they picture is a Cattle Egret are the yellow bill, black feet and, more than anything, the thick, stubby neck. Often, however -- as in the picture -- the bird has his neck scrooched down so you can't see how sinuous it is.

You can compare the above picture with one of an immature Little Blue Heron who often drops by here at http://www.backyardnature.net/n/09/090105cf.jpg.

This Little Blue Heron could almost be a Reddish Egret "white morph" but Reddish Egrets display shaggy heads and necks.

Why should so many herons and egrets be white, at least during part of their lives? One theory is that white birds are harder for prey in the water to see against the bright sky. Clay Green and Paul Leberg at the University of Louisiana tested this hypothesis with mosquitofish and crayfish and found that crayfish reacted the same to white and dark birds, but that mosquitofish actually avoided dark birds more than white.

So, who knows why so many herons and egrets are white?

*****

QUEEN CONCH SHELLS
On eBay Queen Conch shells are going for about US $20 apiece, but around here they're so numerous that visitors pick up only the prettiest. You can see one use a neighbor has for his Queen Conches at http://www.backyardnature.net/n/09/090105qr.jpg.

He's placed dozens and dozens atop fence posts around his property. Other people use them to define driveways and walkways around their homes. By the way, "Propiedad Privada" means "Private Property." A shell of Queen Conch, STROMBUS GIGAS, appears in my hand at http://www.backyardnature.net/n/09/090105qq.jpg.

Is the word "conch" pronounced the way it looks, or like "conk"? I read that originally the word was pronounced "conk" but so many people over the years began mispronouncing it based on the way it looked that now the mispronunciation is usually accepted in dictionaries.

Queen Conches are big snails, and they're having a problem, less because people collect their shells than that people eat them. A NOAA news release in 2003 reported that Queen Conch populations in Honduras, Haiti and the Dominican Republic are exploited at rates that may be unsustainable. Also it says that the US imports approximately 80% of world trade in them, usually more than 1,000 metric tons of Queen Conch meat a year. You can read the whole release here.

Marcia confirms that Queen Conch populations just offshore here are suffering. She says that they come into shallow water when the water is warmest, in July and August, to mate. In the past they were common but now they're so rare that they have a hard time finding one another. Despite having read that you're not supposed to handle them, Marcia is convinced that she sees a bigger problem than being handled, so when they start coming into shallow water she collects them and leaves them in small groups so they can find one another and mate. Local fishermen gather them to eat, making no effort to leave breeding stock. They stab knives into them, pry out the flesh, and leave the shells dumped on the beach -- untold numbers of them. Finding enough bleaching shells to adorn your fence posts is no big problem.

Of course such unlimited hunting is illegal, but so are a lot of things that get done here very much in the open.

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BAYBEANS FLOWERING
I've mentioned how Goat's-Foot Morning-Glory sends very long, robust vines with rosy flowers across the sand stabilizing the ridge between the sea and the mangroves. There's another very long, robust vine with rosy blossoms that's a member of the Bean Family, not the Morning-Glory, is just as common as Goat's-Foot Morning-Glory, and just as sand-stabilizing and ecologically important. It's the Baybean, CANAVALIA ROSEA, shown with its three-foliate (clover-like) leaves and coarse stems scrambling across white sand at http://www.backyardnature.net/n/09/090105bc.jpg.

A close-up of its pretty, bean-flower-type blossom is at http://www.backyardnature.net/n/09/090105bb.jpg.

If you know basic bean-blossom structure (described at http://www.backyardnature.net/fl_beans.htm) you may get a kick out of noticing that Baybean's two-inch- long blossoms are "upside-down" relative to most other bean flowers. The flowers have been twisted around so that their flaring "banners" or "standards" instead of topping the flower now serve as broad landing pads for pollinators at the blossom's bottom. Similarly, the boat-shaped "keel" instead of being on the bottom where it usually is, in Baybean forms a kind of curved crest rising over the flower.

I wanted to introduce you to Baybean just because of its ecological importance and its interesting flowers but once I did a little web researching I almost decided against it. That's because there's a whole subculture of drug-heads out there anxious to get their paws on Baybean's leaves and large, leathery, Lima-bean-like legumes, to use as a marihuana substitute. One "drug shaman" on the Web reports that Baybean seeds have been found in graves in Oaxaca and Yucatan, as well as in Peru, in sites dating from 300 B.C. to A.D. 900.

Beyond all that, Baybean is increasingly used as a biomass cover crop in Third World countries and in arid lands in Australia and Africa where its fast growth quickly covers the harshest soils, diminishing soil erosion.

This is a great plant for tropical xeriscaping. It grows naturally pantropically, and seeds are becoming available on the Internet.

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"RAMGOAT DASHALONG," OR TURNERA
At http://www.backyardnature.net/n/09/090105tu.jpg you see a knee-high herb with 2-inch broad yellow flowers blossoming prettily along the hotel's sandy footpath. Marcia knows an old fellow in the vicinity who salvages every thrown-away or hurricane-uprooted plant he finds, and he had these growing all over his place. The plant is a member of the genus Turnera, probably TURNERA ULMIFOLIA. Three Turnera species are listed for this area so I can't be sure. Turneras are such unusual plants that they have their own family, the Turnera Family, or Turneraceae.

Turnera ulmifolia is a tropical plant with no generally accepted English name. The USDA refers to it as Ramgoat Dashalong, which is colorful enough. Yellow Alder seems to be its most frequent English name, though obviously it's no alder. Maybe the most apt English name I can find is Cuban Buttercup, though it's no Buttercup, either, and lives far beyond Cuba.

Many tropical cultures use Turnera ulmifolia medicinally. Its uses are so numerous and general that you wonder about them. It seems especially useful as an intestinal anti-inflammatory, and research shows that it shows high antioxidant activity.

A closely related and somewhat similar looking species, Turnera diffusa, often referred to as Damiana, also grows here. That species is internationally famed as an aphrodisiac. If you Google "Turnera" you'll get lots of pages selling that species as a "male enhancer."

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TURNERA'S UNUSUAL OVARIES
At http://www.backyardnature.net/n/09/090105tv.jpg you can see part of what make Turnera flowers unusual enough to have their own Family. At first glance the blossom looks completely unexceptional, almost like an Evening Primrose flower. In the picture you see five orangish, elongate anthers encrusted with grainy pollen and affixed atop slender, matchstick-like filaments. These male sex organs are perfectly normal. What's unusual are the female parts. Note the three slender things in the center topped with flaring, hairlike fuzz. The slender items are female styles (ovary necks) and the fuzzy things are stigmas reaching into the air to catch pollen.

Having three styles, each fuzzy-tipped with stigmas, is fairly unusual, but it's even more unusual that the stigmas arise from a single ovary composed of a single cell, and that that single-celled, single ovary is filled with ovules (future seeds) growing from the ovary wall, not its central axis.

Think of an apple. Apple seeds occur in the fruit's center, and if you pay attention you'll see that the seeds' umbilical-cord-like funiculi (sigular funiculus) connect to a core or axis running up through the apple's center. That's the typical way ovules are attached inside ovaries.

At http://www.backyardnature.net/n/09/090105tw.jpg you see how Turnera flowers do it. That's a cross-section of a Turnera ovary about 2/3 the size of a pea. The white, oblong items are developing ovules (future seeds). Notice how they are attached at three locations along the ovary wall -- at 2, 6 and 10 o'clock. Those little stems attaching the ovules to the walls are the funiculi.

When an ovary's ovules arise from the wall like that, it's said to have "parietal placentation." Probably the best-known fruit with parietal placentation is the papaya. Remember how a papaya's black seeds adhere to the wall of the fruit's interior cavity?

So, a pistil consisting of a single cell bearing three styles and having parietal placentation -- that's good enough for a plant to have its own family.

*****

OCEAN GARBAGE/ GARBAGE OCEAN
The other day a visitor who has basked on many beaches throughout the world's tropics found me with black garbage bags picking up garbage from the beach. She remarked that the beaches here are less trashy than in most places she's been. That's because Marcia the hotel owner pays staff to clean the beach far beyond her own property and visitors here showing interest are offered garbage bags and encouraged to pick up trash as they beachcomb. You can see a spot up the beach just beyond Marcia's sphere of influence at http://www.backyardnature.net/n/09/090105gb.jpg.

I had thought that after personally seeing so much rainforest destroyed, so many swamps drained, etc. etc. that I could no longer be shocked. But I am simply appalled at how much garbage is floating in the ocean.

One day the wind blew in acres of semitransparent plastic sandwich bags that must have spelt death to any sea turtle or whale mistaking them for jellyfish. Considerable trash here, such as the plastic, one- portion shampoo dispenser imprinted with the word "Carnival" I found the other day, appear to have been dumped by cruise ships, of which on the average one a day docks down the beach at Mahahual.

Much of what floats onto our beach seems to originate down the coast in Guatemala and Honduras, though I've also found a good bit from the Dominican Republic. I'm guessing that the suntan lotion bottle from Poland I picked up was thrown from a cruise ship, but I simply can't imagine any scenario explaining the drinking- water bottle I found distributed by a purification plant in Indonesia!

An introduction to sea trash is available at http://earthhopenetwork.net/forum/showthread.php?tid=1292.

Algalita's links to technical papers on sea garbage is at http://www.algalita.org/research.html.

Wired Magazine's page on beach trash is at http://blog.wired.com/wiredscience/2008/04/dataset-provide.html.

The Ocean Conservancy's page on coastal cleanup is at http://www.oceanconservancy.org/site/PageServer?pagename=press_icc.

Finally, oceanographer Curt Ebbesmeyer produces a hard-hitting and fascinating quarterly, non-profit newsletter, "Beachcombers' Alert" focusing on what's washing up where, and why. For information on subscribing ($17.50 a year in the US) write to Curt at curtisebbesmeyer@comcast.net.

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SEA-GARBAGE SPIRITUALITY
After picking up garbage for a couple of hours I plop down just beyond the waves' reach. The sand is hot, the wind furious, the waves hypnotic, and the sea profound in a way that takes into account the fact that Life on Earth arose in the sea. And most of the Earth's oxygen, possibly as much as 90%, is produced by microorganisms photosynthesizing within the top 100 meters of ocean water.

On the beach you feel tiny and powerless compared to the sea and the problems facing it. How are you to react? When you know that you could spend the rest of your life picking up beach garbage without really making a noticeable difference, why bother to pick up the relatively tiny bit right around you?

That's where it gets interesting: As I sit looking into the ocean, SOMETHING makes clear that I do need to pick up garbage, even if there seems to be no rational reason for doing so. The sea sends a non- verbal but unmistakably clear message that to simply walk past garbage on the beach is not an act worthy of an enlightened, sensitized human.

The sea conveys her messages the same way and with the same power as does the open sky at night, they eyes of a newborn child, a healthy forest or marsh busy being itself, or any other robust, complex, beautiful natural instance.

In this context, and accepting Nature as "the written Word of God," listening to what the sea says becomes a spiritual communion. And picking up trash along the beach becomes a ceremony of acceptance of the wisdom you have been given.

*****

Best wishes to all Newsletter subscribers,

Jim

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