JIM CONRAD'S
NATURALIST NEWSLETTER
Written at Hacienda San Juan Lizárraga
one kilometer east of Telchac Pueblo, Yucatán, MÉXICO
and issued from Hotel Reef Yucatan 13 kms to the north

January 22, 2006

FOUR BROWN PELICANS AND A LAUGHING GULL
It's normal to see individual Brown Pelicans flying up and down the beach 15 or 20 feet above the water and just offshore. Spotting fish they spectacularly dive headfirst into the waves. Usually they don't catch anything and then sit for a minute or so bobbing on the waves. Finally they fly off, flapping hard while running atop the water a few steps before getting aloft.

Sometimes the pelicans join into small flocks, however, and then their fishing becomes methodical, almost obsessive, in the manner of American football players during a close game. In these small flocks, after their dives they rest just a few seconds before taking off again, and typically fly only for about 15 seconds before diving again. The other day I watched four Brown Pelicans work back and forth in this manner before Hotel Reef.

It was low tide and the birds flew close to one another in a tight formation. They'd pass over a dark bed of seaweeds, one would shift his wings showing he was about to dive, the others would do the same, and they'd all dive together, hitting the water at about the same time, and within just a few feet of one another. My impression was that instead of going after fish they'd spotted they were making random dives into the seaweeds, maybe depending on the shock of all their bodies crashing into the bed to cause fish hiding among the seaweed to abandon their cover. Sometimes one or two other pelicans would join the flock, but sometimes the flock was reduced to as few as three.

All the time I watched, a single young Laughing Gull in his second-winter plumage tagged along.

The gull always waited two or three seconds after the pelicans had taken off before he himself would take wing. He'd follow behind the flock maybe 50 or 100 feet, then once the pelicans had dived he'd sail in among them maybe three to five seconds later.

Most of the time the gull would land atop a pelican -- usually on the back but sometimes atop the head! I think the gull's game was to catch stunned or wounded fish that might briefly escape a pelican's beak, or maybe the gull, like the pelicans themselves, was just trying to catch fish scared from cover by the pelicans' crashes.

The gull landed on different pelicans who didn't make much of an effort to keep him off, other than occasionally shuddering their bodies or halfheartedly tossing their heads. They seemed to have accepted the notion that if a seagull wants to land on you there's not much a pelican can do.

*****

BRYOZOA ON THE BEACH
Occasionally on the beach I find white, rocklike, oddly formed items most often just a couple of inches across. Until now I've assumed that they were pieces of coral washed ashore. This week I came upon such a pretty piece that I had to examine it more closely. You can see what I found held in my hand at http://www.backyardnature.net/yucatan/bryozoa1.jpg.

Two features of the item made me wonder whether it really was coral. First, in several places the item was sheetlike, and the thin, overlapping sheets had clearly grown onto and around some seashells, embedding the shells within the structure's matrix. Second, even the naked eye could see that the sheets were composed of many rectangular, contiguous cells systematically arranged like cells in wood. This didn't look like coral at all. You can see a close-up of the cellular structure and how a seashell was embedded in the matrix at http://www.backyardnature.net/yucatan/bryozoa2.jpg.

With some Googling on the hotel computer I realized that indeed it wasn't coral, but rather something known as calcareous bryozoa. Well, that set off a flurry of studying and figuring out. Here's part of what I learned:

When on the beach you find white, rocklike chunks of either bryozoa or coral, you're finding the remains of colonies of tiny animals, with the animals now dead and gone. Cells of the individual tiny animals are cemented to one another mostly with calcium carbonate (the same as limestone). The individual tiny CORAL animal is referred to as a polyp while the bryozoa unit is called a zooid. A discussion of the differences between coral and bryozoa can be reviewed at http://www.bio.umass.edu/biology/conn.river/corals.html.

And there are big differences. Corals and bryozoa are in completely different taxonomic phyla. You can grasp the significance of that when you realize that all animals with backbones -- birds to fish to mice and humans -- belong to the same phylum. Thus there's more difference between a coral polyp and a bryozoa zooid than between a hummingbird and a hippopotamus.

The individual bryozoa zooid, though tiny, is much more complex and highly evolved than a coral polyp. A typical zooid looks like a tiny, upside-down octopus on a stem. A nice diagrammatic illustration showing one, and how its cell connects to neighboring cells, is at http://www.civgeo.rmit.edu.au/bryozoa/bryointr.html

I first heard about bryozoa when taking geology classes in college. The bedrock of much of central Kentucky and Tennessee, as well as other large areas of North America, is composed of limestone in which fossil bryozoa are often abundant, sometimes constituting most of the rock itself. Typical bryozoa fossils clearly show the flat sheets of tiny, highly ordered, rectangular cells seen in my beach specimen.

Not all bryozoa species are marine with their zooids cemented together into colonial, rocklike structures. Some species live in freshwater and some bore into calcareous substrates such as limestone instead of secreting their own shells. See a taxonomic overview of past and present bryozoa types at http://www.ucmp.berkeley.edu/bryozoa/bryozoasy.html.

Of course there were no elegant little bryozoa zooids in the chunk of white calcium carbonate I found this week on the beach. What I had was like a city block of abandoned houses in an abandoned city. Who knows what disaster had caused it to be lying there instead of being home to a thriving community of pretty zooids in the Gulf's warm, shallow waters?

*****

AN OPOSSUM AND ITS NAME
We have Opossums here, the same species as in North America, DIDELPHIS VIRGINIANA (http://www.backyardnature.net/opossums.htm) The other day when gardeners Roberto and Francisco found one hiding among cinderblocks in a hurricane-ravaged building they called for me to come see it.

"It's a Zorro," they said, assuming I'd never seen one before.

That name surprised me because in the rest of Mexico Opossums are called Tlacuaches, and the word zorro refers to a male fox.

I got the mammal book and showed them the picture of a fox and asked them what that was.

"Gato de Monte," they agreed. That name translates to something like "Cat of the Woods," and I was even more surprised that these animal-savvy men would call a fox a cat.

In my December 19, 2004 Newsletter I observed that Yucatec Spanish is more tilted toward the Spanish spoken by the conquistadores than in most of Mexico. In most of Mexico, Castilian Spanish has been much more enriched with words from native Indian languages than here. Thus here a turkey is called a pavo, which is standard Spanish, but in most of Mexico it's a guajalote, a native Indian word.

It's interesting that when most European nations colonized developing countries their people generated wonderful bodies of literature describing native customs and local biology. I don't find nearly so much of that kind of writing in Spanish. In the Yucatan we have Bishop de Landa's treatise, but he wrote that only after burning all the Maya books, and murdering many Maya who weren't accepting his religion fast enough. The conquistadores sought money, the advancement of Catholicism, and not much more

I wonder whether the Yucatec-Spanish designation of opossums as foxes and foxes as cats might be an artifact of the conquistadores' frame of mind? Maybe the conquistadores simply didn't care enough about anything other than money and religion to be concerned about the names of the native things around them.

*****

RED-BLOTCHED RATSNAKE IN A CABINET
The other day Darwin was moving an old cabinet in one of the guesthouses when he saw a boldly patterned red, black and white snake about 15 inches long on the cabinet's floor. His first thought was that it was a venomous coral snake, but then he remembered that corals have bands, not big blotches like this one. Still, the coloration looked dangerous and he was good enough to call me.

It was a young Red-blotched Ratsnake, ELAPHE FLAVIRUFA, which you can see wrapped among my fingers in a picture taken by Vladimir at http://www.backyardnature.net/yucatan/ratsnak1.jpg.

One nice feature of that photo is that is shows so nicely the typical ratsnake flat bottom. If you make a cross section of a ratsnake it'll be shaped like a slice of bread, rounded on top, with flat sides and a flat bottom. As you'd expect, right angles are formed where the flat sides and flat bottom come together. These sharp angles help the snake keep its grip while climbing among tree limbs.

My herp book says that this species is distributed from central Mexico to Nicaragua, but that throughout its range it doesn't seem to be common anywhere. It occupies many habitats, though, from very dry forests to tropical wet ones, and it has been found eating rodents, bats, birds and lizards. When Katharine heard this she decided that this may be the reason why mice hadn't been a plague in that particular building.

When Doña Lupe the maid saw the snake she confidently pronounced it a young rattlesnake, no doubt about it. I suspect that the vast majority of folks here would have said the same, and they would have dispatched the pretty snake forthwith. The Doña didn't seem too pleased when we released our find into a nearby stone wall.

Several flat-bottomed ratsnakes of the genus Elaphe occur in North America. I have a friend in Kentucky who named his kids after snake genera and one of them is called Elaphe. Ratsnakes will bite you if you bother them, though of course their bite is not venomous. This little fellow tried to bite me but I don't think his small teeth could have done much damage. The species grows to five feet or more, however, and I wouldn't carelessly handle one of that size.

*****

BAUDIN'S TREEFROG
According to my herp fieldguide we have three treefrog species here. Farther south and east where rainfall is greater, the forest more luxuriant and there's a higher species diversity, there are others. Our most commonly encountered treefrog species here is Baudin's Treefrog, SMILISCA BAUDINII, shown at http://www.uga.edu/srelherp/jd/jdweb/Herps/species/ForAnuran/Smibau.htm.

My first encounter with Baudin's Treefrog was about a month ago when one appeared on an arching, shaded date-palm petiole about a yard off the ground, crouching there in full view, day and night, for several sunny, very dry days. He was pale green and stood out against the palm's dark green foliage. I don't think I've ever seen a treefrog perch so conspicuously in one place.

My latest encounter was one morning this week when I flushed the commode in a bathroom with a door that's kept open. This one, pale brown with dark brown banding and spotting, had been hiding up under the seat's rim and he almost got flushed into unknown territory. At first it was hard to believe that this dark-banded frog was the same species as the pale green one I'd seen earlier.

Baudin's Treefrogs are distributed from southern Texas to Costa Rica, and they inhabit a wide variety of habitats, from our scrubby forests to high-elevation cloudforests, to low-elevation rainforests.

The herp book says that sometimes after rains this frog emerges in incredible numbers. There's one report of an outbreak of the species "so numerous on the trees as to bend down the branches." Their call is a series of loud, short, explosive WONK-WONK-WONKs. This is a much more robust species than I'm accustomed to in North America.

*****

FUNERAL ASUCENA
Last week I mentioned the death of Roberto the gardener's father, the man who remembered what Su-tut's spiraling fruits were good for. I attended the good man's dignified funeral.

A goodly number of the community gathered in the blocked-off street before Roberto's house, inside which the old man lay in his coffin. A hearse arrived, the coffin was carried into it, and then we all walked behind the hearse as it very slowly made its way to the old cathedral about five blocks away. It was a summery, sunny day with grackles screeching among the palms and the flamboyáns heaving in afternoon breezes. Many of us walked carrying bouquets of flowers, leaving a powerful perfume behind us.

At the end of the Catholic mass the coffin's lid ceremoniously was nailed in place, the coffin again was carried to the hearse, and now the assemblage slowly walked to the cemetery about a quarter of a mile away. At the cemetery as soon as the coffin was lowered into its pit men began carrying buckets of fresh cement they'd had waiting, and poured a concrete slab atop the coffin. Then the flowers we'd been carrying were placed around the fresh grave and the ceremony was over.

This week, eight days later, we met again at Roberto's house. A great deal of praying was done, facing a table overflowing with fragrant blossoms and flickering candles. Then we walked again to the cemetery, carrying the flowers with us. Now the concrete slab atop the grave was painted a bright blue-green, and was protected by white-painted, ornamented, concrete enclosure. We replaced the old flowers with our new ones and again a great deal of praying was done.

Some say that this second ceremony has no special significance, that things are just done this way. Others claim that when the body dies the spirit hangs around its home wandering for eight days, but then it's ready to follow the body, and we helped the spirit find its way to its new place.

How poignant had been the odor of all those flowers, all the time. The most commonly brought flower was one not often considered in North America. It was a native Mexican species much planted here at the hacienda, adored not because of its blossoms, which are white and rather modest looking relative to the most bodacious of lilies, but because of its penetrating and glorious fragrance.

Here it's called Asucena and the books give its English name as Tuberose, though I see nothing about it suggesting a rose. It is POLIANTHES TUBEROSA, placed in the Agave Family or Amaryllis Family, depending on the expert. You can see it at http://www.tntuberoses.com/

*****

CAPO THE OBNOXIOUS GANDER
We have three large geese here who impact my quality of life substantially -- with their midnight honkings and all the poop they leave on my doorstep. They overnight right outside my door and it's a mystery to me why they choose my place and not ten thousand other spots that to my eye look as good.

There are two females and one male. The gander is called Capo. I'm told that "Capo" is an Italian word that might be applied to a thuggish gang leader.

Capo terrifies visitors by lowering his long neck level with the ground, then running straight at them, his total attention clearly focused on the kneecaps. After his attacks -- which never involve actual physical contact -- he turns around, points his head skyward, honks hugely, and struts back to his two lady geese, who softly squeak in a manner seeming to say, "Oh, Capo, thank you for protecting us... "

Capo enjoys his job as protector enormously. I know he enjoys it because now that he's certain I'll just ignore him he's taken to running at me ten to twenty times each day. In fact, this week he's begun attacking my front door even when no one is at home. At the end of each of his door-runs he pokes his proud head skyward, honks triumphantly, and shamelessly struts back to the ladies who squeak their heartfelt appreciation.

I think Capo has become addicted to this behavior. It's a quick, easy, safe way to gain instant gratification, so you can understand its appeal to him.

Of course I can't see all this without reflecting on how often the same behavioral syndrome expresses itself among us humans.

Someone in a passing car yells an insult at a pedestrian he doesn't like the looks of. A politician wants his poll numbers to jump, so he stirs up fear about terrorists and proposes repressive laws. It's all the same stuff, all safe, ego-satisfying, instant gratification.

But, maybe our lady geese are catching on. The last couple of days when Capo has attacked my empty house their squeaks of appreciation have sounded singularly unenthusiastic, even a bit peeved. Sometimes they don't squeak at all, no matter how Capo trumpets his achievement and struts after his runs.

I wonder how long it'll be before we humans stop responding with mindless hurrahs to the self-serving flag waving and chest thumping of our own Capos?

*****

Best wishes to all Newsletter subscribers,

Jim

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