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JIM CONRAD'S
NATURALIST NEWSLETTER

Issued from Sierra Gorda Biosphere Reserve Headquarters in
Jalpan, Querétaro, MÉXICO

May 19, 2007

NEOTROPIC CORMORANTS & THEIR EGRET
Tuesday morning at daybreak a glimmer of silveriness ignited in the dim light along the reservoir's opposite shore where the water was particularly shallow. My binoculars showed water being churned up by a school of small fish under attack by two Neotropic Cormorants. A Snowy Egret ran back and forth along shore stabbing at fish driven close to the bank.

The school was simply being ravaged. Nearly every time a cormorant surfaced a squirmy little fish shined in his beak for a second before being gulped down. Then immediately the cormorant would submerge again. Why didn't the fish swim into deeper water? For one thing, large bass were out there, just as hungry as the cormorants. For another, cormorants dive deeply for their meals, too, as do the Coots and Pied-billed Grebes, who also were in the neighborhood. Generally schools of small fish are lucky if just one or two fish graduate to adulthood.

In this year's January 26th Newsletter I described how a Snowy Egret would regularly locate schools of fish in open water, land amidst them and vigorously stab at them with his beak, then within seconds several Neotropic Cormorants would come zooming in, crashing into the water around him, and join in the marauding. I wonder if this is the same Snowy Egret, and the same cormorants?

Neotropic Cormorants extend as far north as southern Texas, southern Arizona and southwestern Louisiana, sometimes straggling clear to Canada, and they're expanding their distribution northward. Except in their breeding plumages they can be hard to distinguish from North America's Double-crested and Great Cormorants. You can see a Neotropic Cormorant at http://sdakotabirds.com/species/neotropic_cormorant_info.htm.

Also you can see a small flock on a spit in Jalpan Reservoir (notice how low the water has dropped by the markings on the pier-like thing's cement legs) at http://www.backyardnature.net/n/07/070519cm.jpg.

After you've watched Neotropic Cormorants awhile you notice that they're markedly smaller than the northern species. The Double-crested is 33 inches long while the Neotropic is only 25 or 26. Of course when birds are alone it's very hard to judge size but, relative to the northern species, Neotropics do give an impression of being more compact and of moving with greater economy. I've seen only one Double-crested Cormorant at the reservoir and it was perched right beside some Neotropics. The size difference then was very conspicuous.

A lot of people don't like cormorants of any kind, especially fish farmers. On Mississippi Delta catfish farms I've seen the depredations cormorants are capable of.

However, when studies are made taking into account the cormorants' benefits as well as their obvious disadvantages for fish farmers, it's not always a clear-cut situation. Mainly, cormorants extract sick fish from ponds since those are easier to capture. In the stressed, overpopulated environment of any fish farm, one sick fish can quickly cause a costly epidemic among all the ponds. The value of cormorants culling slow-moving, sick fish shouldn't be underestimated.

Also, cormorants contribute greatly to aquatic ecosystems. By removing the most numerous species they promote fish diversity, thus enhancing ecosystem stability. Because of their high mobility, cormorants transport snails and other invertebrates, algae and various plant propagules between water bodies, further enhancing diversity. Maybe the greatest service they provide, however, is that of fertilizing the aquatic ecosystem with their plentiful guano.

*****

ZEBU CATTLE
The most conspicuous breed of cow seen around here is the big, white one shown at http://www.backyardnature.net/n/07/070519zb.jpg.

That's a Zebu, called Cebú in Spanish, or at least a cow with a lot of Zebu in it. Zebus have more sweat glands and are more resistant to tropical diseases than European breeds, so they are famous for their ability to thrive in hot climates. Their ancestors came from India and Brazil. Zebu can be recognized by the loose fold of skin, or dewlap, sagging beneath their necks, their long, drooping ears and a conspicuous, fleshy hump over their front shoulders. The one in the picture doesn't have much of a hump but I've seen old males with enormous ones.

Regular dairy and beef cattle are known by the Latin name of BOS TAURUS. Zebus are so different from most regular breeds that in the past they were usually considered a completely different species -- BOS INDICUS. However, now all the various breeds are lumped together. That seems right, since a part of the species concept is that distinct species generally don't interbreed to produce fertile offspring, and Zebus are regularly interbred with many other kinds of cattle.

Several distinct breeds or races have been derived from Zebus. There's the Gir, the Guzerat, the Afrikaner, the Red Sindhi, the Chinese Southern Yellow and several more. Brahmans of rodeo fame originated in Texas as a result of mixing various Zebu races. You can see six Zebu breeds pastured in Mexico at http://www.cebumexico.com/razascebu.html.

*****

MEXICAN RACERS (OF THE SNAKE KIND)
Compared to my earlier bases in the Yucatan I've seen very few reptiles in this part of Mexico. I miss the Yucatan's dog-size Black Iguanas and almost weekly adventures with this or that snake. We do have lots of small lizards here, but none whom you can get to know, like the Green Anoles who used to hang on my walls as I computered in Mississippi, or the dominant-male Black Iguana who'd watch me each morning last year as I'd cook breakfast in the ruins of the old henequen mill at San Juan. Here we certainly have good habitats for reptiles. I suspect the reason there are so few snakes is simple: Many generations of humans indiscriminately killing them has taken its toll.

Therefore, I was really tickled to catch a glimpse of a snake this week not far from my casita, in weedy scrub on the other side of the fence. It was a three-ft-long, slender, black snake with smooth scales and a decidedly bluish cast. Though he moved too fast for a good look, he couldn't have been anything other than a species I've written about several times before, a Racer. You might recall that Racers are distributed from Canada to Guatemala. This time last year in Kentucky one explored mole tunnels in my yard. Once I described how one wrestled with a frog in Mississippi before swallowing him, and in California I bemoaned the local house cat killing one.

About ten sometimes-intergrading Racer subspecies are recognized, the one we have here being known as the Mexican Racer, COLUBER CONSTRICTOR OAXACA. The literature habitually describes our subspecies as greenish gray, but the one I saw was blue-black, so I don't know what's going on.

Whatever the deal, I'm awfully glad to see that at least one snake is surviving in the neighborhood.

*****

CURLED BEAN PODS ALONG SIDEWALKS
Suddenly something new is appearing in the trash thrown along sidewalks and in the streets. It's a knobby looking, curiously curled, fair-sized bean pod, and usually it's been pried open and robbed of its beans. I knew what they were when I first saw them because I've been waiting for them. For weeks I've watched the pods ever so slowly maturing on medium- sized trees abundantly appearing as street trees and in people's yards. At last those pods are maturing, and each day you see people with long poles poking at high-hung pods.

Some of those trees grow here among the reserve's office buildings, so naturally Don Gonzalo fixed himself a 15-ft-long bamboo pole with a hook on it. You can see his creation, along with some hook- snatched, knobby, curled-up pods lying in my hand, at http://www.backyardnature.net/n/07/070519gu.jpg.

Note the Don's ingenuous manner of securing a hook onto the bamboo pole. A backward-pointing stick inserted into the bamboo stem's hollow interior has been secured with string, and made to angle outward by a wad of green leaves stuffed beneath the stick and filling the cavity. When snagged with this pole the pods stay wedged within the hook instead of falling to the ground. People up north in fig-picking territory should remember this design.

The pods are produced by a tree member of the Bean Family, PITHECELLOBIUM DULCE. In English the main name for it appears to be Manila Tamarind, but that's unfair, since it's a native Mexican tree and was introduced into Manila, as it also was in many other tropical areas. In Hawaii it's even become a weed tree. Around here the tree is called Guamuchil.

When the legumes mature they acquire a rosy blush on their exterior, split, and expose a white, pulpy material inside which black, shiny beans are embedded. You peel open the pods the way you would a big garden bean, eat the white stuff, and throw away the hard, black bean. Some trees produce sweeter pulp than others.

Botanically, the edible white pulp is the seed's "aril," which is an outgrowth from the funicle, which is the umbilical-cord-like thing connecting the seed to the pod's midrib. In some seeds arils are bright and showy, helping attract potential, hungry seed-disseminators.

The "dulce" in the species' Latin name led me to expect the white aril to be sweet, since that's what "dulce" means. However, I found it about as bitter as it was sweet. In my opinion, this is another example of nature creating something that's good-tasting enough to make you snack on it as you walk down a road, but not good enough to make a memorable meal.

Local Mexicans seem to relish them much more than I. The pods are even on sale in the market. I expect it's one of those cultural things, like Limburger cheese or gefiltafish: You have to be born into the culture to really appreciate it.

Guamuchil's leaves are easy to recognize. At http://www.backyardnature.net/n/07/070519pc.jpg you can see how the compound leaves alternate upon the stem. Each leaf consists of two leaflets which in turn are divided into two asymmetrical leaflets, looking like butterfly wings. Therefore, each leaf consists of four leaflets.

*****

COW OKRA
Another tree at its peak of producing edible pod-fruits right now can be seen at http://www.backyardnature.net/n/07/070519co.jpg.

Notice how those nine-inch-long pods, instead of dangling from branches, can grow right off the trunks, like cacao fruits. In Belize I learned to call the fruit and the medium-size tree producing them Cow Okra. It's PARMENTIERA EDULIS, called Chote around here, but Cuajilote in much of the rest of Mexico. It's a member of the Bignonia Family, along with North America's Trumpet Creeper and Catalpas. The leaves are compound 3- or 5-foliate, with a short, stiff spine at the base of each petiole.

In my "Plantas Medicinales de México" I read that in the Yucatan an infusion made from the roots is used to control diabetes. Since I have hypoglycemia, which also is a problem with the blood-sugar level, I thought maybe I could experiment with eating the fruits. Also, elsewhere I learned that the Aztecs used the plant for renal diseases, indigestion, colds, and ear infections. Supposedly each day they drank tea made from 50 grams of leaves in one liter of water. For ear infections they soaked a cotton ball in this mixture and inserted it into the ear.

At http://trophort.com/003/164/003164018.html you can review an abstract of a scientific paper describing how chloroform extracts from Cow Okra reduced blood glucose levels in diabetic mice by 44%, and 30% in normal mice.

Tasting some raw fruits Don Gonzalo brought me I found their taste to be not bad, even without the sugar the Don suggested I sprinkle on them. Their rinds are too tough and fibrous to eat but inside they have the texture of cucumbers, and are filled with many small seeds that are easy enough to ignore and swallow. My friend Pancho told me that the best way to prepare the pods was to roast them in an oven, covering them with ashes and embers. As they bake they soften, sweeten, and get juicier. He says that people used to eat Cow Okra all the time but now they don't bother, the taste being good but just not having the pizzazz people expect nowadays.

I baked several in my solar oven, not really expecting to care much about them. However, as soon as the pot's top came off and a rich, molasses aroma poured out I knew I was onto something good. To me the gummy flesh tasted like campfire-baked plantains (those really big bananas), though others who gathered around wanting a taste said it was more like sweet potatoes, and the pods were so sweet and gooey that I was accused of packing them in brown sugar, or piloncillo. They were delicious, but fibrous; I had to pick fibers from my teeth for hours afterwards.

What a marvelous thing this Cow Okra is, and what a treat that I got to introduce it to some young Mexicans who'd never even noticed it growing along their streets and at the ranchos of their country cousins.

Cow Okra is native to Mexico and Guatemala.

*****

ANTS IN MY CASITA
I've mentioned how life in rural and small-town Mexico reminds me more of my childhood in rural and small- town Kentucky, back in the 50s, than rural and small- town Kentucky does today. One of the similarities is ants. On hot summer days back then lines of ants infiltrated our kitchen no matter how hard we tried to keep it clean. Ants in the sugar bowl, ants in the cereal box, ants up and down the molasses jar. Clean the cabinets again and again, wash with detergent, change the shelf paper, and ants still found something, maybe a loosely wrapped cube of yeast or a bag of meal with a pinprick in its bottom.

You'd think that my tiny casita, with a concrete floor just wide enough to lie stretched-out on, and the only furniture consisting of a metal desk, a chair and a tall, gangly, four-tiered wooden platform with open sides, would be easy to keep clean enough to keep ants out. But, sweep and scrub as I may, the ants just keep coming.

They eat holes in the plastic bags holding my peanuts, leaving me empty shells. Two or three dry flakes of oatmeal spilled accidentally when I shoveled out my breakfast fuel an ant-line for hours. I keep vinegar in a plastic bottle with a tightly fitting lid and right now on the shelf I see a whole platoon of ants dangling on the lower rim of the bottle's blue cap, apparently feasting on what I can't see, can't imagine what might be there, and just can't seem to clean off.

What's impressive is that these ants make such efforts and endure such sacrifices for the sake of such tiny measures of food. Just look at the deadly, strenuous long-march they make to harvest the slight film of milk inside my milk carton, which I rinsed before putting aside.

In a way, this week's ant wars, the cormorants depredating schools of fish, and even the slight sweetness/ slight bitterness of the Guamuchil pods all contributed to a "message" Nature seems to have been sending me all week.

For, every time someone accidentally steps on my ant line you can see in terms of squashed ants the sacrifices the ant colony makes for three or four flakes of dry oatmeal. How many eons did it take for ant-colony-wisdom to incorporate the understanding of how many dead citizens a few calories of carbohydrate are worth? Similarly, how many thousands of cormorant generations endured cyclical fish famines before evolution programmed cormorants to eat just so much, then spend hours with their wings spread out, warming in the sunlight? How many generations of Guamuchil trees produced pods too sweet or too bitter before just the right balance was accomplished to assure that the white aril was sweet enough to attract seed-disseminators, but was bitter enough to avoid wholesale destruction through overeating?

Unless one is blinded by the dangerous belief that for some reason the Universal Creative Force has granted the Earthly human animal a special dispensation from Nature's laws, then it should be clear that ants, cormorants and Guamuchil trees all reveal profound wisdom relevant to our own species' long-term survival.

Moreover, having good brains, we humans should be able to avoid Nature's usual way of settling accounts -- through starvation, conflict and diseases -- by rationally and voluntarily controlling our numbers and appetites.

*****

Best wishes to all Newsletter subscribers,

Jim

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