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

March 11, 2006

MANTA RAY
Folks at Hotel Reef are good about letting me know if they spot an unusual plant or animal. This week I was told that a fishing tour had just returned with a Manta Ray caught with a rod and reel about three miles offshore.

Immediately I set off to the pier the fishing tours return to, but by the time I got there all that was left of the ray was a four-ft-wide, somewhat rhomboid sheet of flesh with an elliptical hole cut in the middle. The sheet of flesh, with a skin texture like rubbery, dark-gray sandpaper, was the ray's wings, and the hole was where the now-discarded body had been. White cartilage showed at the pink flesh walls of the ragged cut. A rope through the hole bound the remains to a pier post, and the choppy water's currents caused the wings to undulate, but not in the coordinated manner of a living thing. It was just a sheet of dead flesh drifting aimlessly back and forth, back and forth.

It was a sad first encounter with a Manta Ray. On TV I'd seen them gracefully flying through blue water. I was stung by the moment, finding myself standing there both thinking how wonderful it was that such an exotic life form existed just offshore the hotel, and at the same time witnessing its degradation, there, tied bodiless with a dirty, plastic rope to a pier.

Back at the hotel I told one of the watchmen that I'd never seen a Manta Ray, and that I was surprised how large it was. He laughed and said that not far offshore there was a submerged rock, probably the remains of a coral reef, where divers always saw one a little over 4 meters across -- 13-½ feet. I wasn't sure whether I should believe this so I Googled the matter and was astonished to learn that Manta Rays get up to 9 meters across -- 29.5 feet! You can see the fine webpage I got, from the Florida Museum of Natural History, all about Manta Rays, including a map showing their pantropical distribution, at http://www.flmnh.ufl.edu/fish/Gallery/Descript/MantaRay/MantaRay.html.

Inlander that I am, I was not at all sure how to classify Manta Rays, though the sandpapery skin suggested a kinship with sharks. All became clear when I read in Vladimir's biology textbook that rays, MANTA BIROSTRIS, are "...flattened sharks that live on the sea bottom." Even though Manta Rays are sharks, the above page says that they are of minimal danger to humans. We're not talking about stingrays here; that's a different story. The textbook went on to say that today there are about 275 shark species.

What other wonders lie right off these beaches I walk each week, and what other outrages? That Manta Ray, obviously a young one, deserved to live, if only in terms of "diving tourism," to be visited by people willing to pay to see it alive and free.

*****

BRONZED COWBIRDS ARRIVE
At the hacienda we have three commonly encountered, completely black perching birds: Great-tailed Grackles, Groove-billed Anis and Melodious Blackbirds. The other morning while sitting next to my breakfast campfire I saw three black birds land in a nearby Neem tree and they did not behave like any of those three, common, black species.

For, suddenly one of the birds rose on his spindly legs, spread his wings, puffed out his body especially in his neck area, and approached one of his companions slowly pumping his torso up and down. Unable to defend myself from a flash of anthropomorphism, the image evoked was that of a pervert with his black overcoat opened wide to reveal his naked body, tiptoeing and lewdly thrusting his pelvis as he approached his victim.

When the bird turned his head in a certain direction and I saw that his eyes were bright red, I knew that the black-overcoat image wasn't as absurd as it might seem. For, this was a Bronzed Cowbird, sometimes known as the Red-eyed Cowbird. And like its northern relative the Brown-headed Cowbird, this bird is a "brood parasite." The female lays her eggs in the nests of a wide variety of other bird species, which then incubate the cowbird's eggs and raise the nestlings to maturity, often to the detriment of their own nestlings. You can see a Bronzed Cowbird at http://www.mbr-pwrc.usgs.gov/id/htmsl/h4960pi.jpg.

Bronzed Cowbirds are distributed from southern Texas and New Mexico through Mexico to El Salvador and Honduras. The North's Brown-headed Cowbird makes it to central Mexico, but not to here.

I read that during the winter Bronzed Cowbirds join into large flocks with other blackbirds but that during the rest of the year they travel singly or in small groups. Maybe what I'm seeing now is a wandering small group after the winter flock has broken up. All three, which hung around all week, are males, so maybe they're "scouting" before females arrive. At first they never sang, but now rarely you hear a quick, subdued squeal a lot like the Brown-headed Cowbird's.

Maybe this is the first hint of our birdlife readying itself for the rainy season, for other bird species are subtly changing their behaviors as well. The White-wing Doves are cooing much more exuberantly than usual. Little Ruddy Ground-doves regularly do combat upon the stone walls -- though they appear to nest all winter, so I'd not expect much of a change in them. Two months ago I watched a mother Ruddy Ground-dove defend her nest heroically against four Yucatan Jays who uncoordinatedly approached her nest from all directions, apparently hoping for an egg or nestling meal. Tropical Mockingbirds sing more vociferously than usual and during my campfire breakfasts each morning the Southern House Wrens more vigorously than I remember chortle, warble and trill their songs, sometimes atop rocks just a few feet away.

Maybe for some bird species the deal is this: Courtship now leads to nestlings just as the rainy season returns in May, when bugs will be abundant again. Maybe the Bronzed Cowbirds have arrived in preparation for that ample nesting time.

*****

ROBERTO'S VERSION OF COWBIRDS
One morning I told Roberto the gardener about the Bronzed Cowbirds' arrival. He knew them by their Maya name, and he didn't want to believe my version of their nesting habits.

"That bird makes its own nest," he said, "but the strange thing about it is that two kinds of nestlings are produced -- one is black and one is yellow."

I could just imagine how this story got started, someone finding an oriole's parasitized nest in which both cowbird and oriole nestlings were being reared. Trying to make sense of what they saw, they guessed that the wrong bird species was the parent, and then that faulty information was passed on and on. There's so much like this in Indian lore, where there's a valuable grain of truth, but where you're wise to not depend too much on a story's complete accuracy. Information about medicinal plants often is like this.

But, just think: Roberto could distinguish the cowbird from the other black bird species we have here -- something that takes a new birder some time to do. Also, he knew its name in Maya, and he knew something fishy was going on with its nesting. These older Maya folks know so much about the world around them, and what a shame that so little is being passed on to their new generation.

*****

GREAT HORNED OWL NESTLINGS
Atop a topless wall jutting into free space at the side of the hurricane-ravaged, old henequen mill next to my lodging, during each of the last several years a pair of Great Horned Owls has produced two offspring. It's not clear whether the parents are the same owls each year, but we like to think that they are.

For the last few weeks I've ended my tours of the hacienda by taking folks to see the mother patiently sitting on her nest, visible as two ear-tufts rising from a mat of brown grass that's established itself atop the ruined wall. Always two or more large Black Iguanas encircled her, facing the nest, and it sure looked as if those iguanas were waiting for the right moment for an egg or nestling meal. Remember that at Komchén last year we had problems with Black Iguanas eating eggs in the hen house.

About a week ago one morning the mother appeared to be off her nest, showing herself from the chest up. I guessed then that the nestlings had hatched and that now they were large enough to displace the mother. This Wednesday two fuzzy little heads appeared next to the mother, the iguanas were gone, and the father was flying around carrying in his talons the gut-dangling remains of what was probably a rat, but could have been an iguana. The nestlings were surprisingly unlike one another in their faces. Atop their heads their future "horns" were no more than low, bushy bumps.

Species-wise, this is the same Great Horned Owl, BUBO VIRGINIANUS, that North Americans know, the one that goes hoo, hoo-hoo-hoo hoo-hoo, more or less. The species enjoys an especially large distribution, being found from northern Canada and Alaska to Tierra del Fuego in extreme South America. Its habitats range from arid deserts to humid evergreen and deciduous forests, and dry, hacked-up scrub like ours. During my first months here I heard them every night, but lately they've been quieter.

By the way, our many Ferruginous Pygmy-owls are as conspicuous with their pulsating calls as ever. Occasionally at night I hear a Barn Owl and Darwin has seen his white form silently sweeping past him as he biked from town late at night. We are also supposed to have Vermiculated Screech-owls, Mottled Owls and possibly Burrowing Owls here, but I've not seen them.

*****

VARIABLE CORAL SNAKES AT DUSK
Until recently I've been fond of telling everyone that, despite the local belief that many kinds of venomous snakes are abundant here, I've never seen one venomous species in the northern Yucatan. I have indeed seen many snakes the locals claimed were venomous, but which were perfectly harmless, especially "false corals." My impression has been that, in terms of dangerous snakes, this area is much, much safer than, say, southern Mississippi with its many rattlers, cottonmouths and copperheads.

Monday at dusk as I approached my lodging a two-ft- long Variable Coral Snake, MICRURUS DIASTEMA, lay upon the steps right before my door. It was almost dark but I could plainly see the red, black and yellow banding of the snake's body, and I was able to lean over the snake and confirm the pattern sequence needed for a snake to be a dangerous coral and not a harmless mimic. Paying close attention to what I saw, I recited this little poem under my breath:

"Red on yellow
Will kill a fellow... "

In other words, to be a real coral snake -- at least in this part of the world -- the banding must be arrayed so that the red bands are always bound by narrow, yellow bands. It must look as if a red band has been affixed atop a larger yellow band, with just the edges of the yellow band showing at the red band's edges.

That's what I saw. One of the mimics here, the Red Coffee Snake, also can have its red areas framed with yellow, but its black parts are mere spots on the back, not solid bands completely encircling the body. I definitely had a coral snake here.

Moreover, now that I saw how the snake behaved I grew convinced that another snake I'd encountered at dusk, also on some steps nearby, also had been a coral. It had been too dark then for me to see the colors, but I clearly saw the shape, the banding and the behavior. The behavior these two snakes shared was this: When the snake grew agitated he squirmed much more vigorously than normal for an escaping snake on a smooth surface, and every couple of seconds the snakes would suddenly launched their heads upwards and snap the air two or three times before falling back onto the ground and continuing to squirm.

Up north when I find rattlers, cottonmouths and copperheads in places where they might hurt people, I put them into buckets and carry them to more isolated places. These snakes behaved far too violently and aggressively for me to fool with them, and they graciously escaped into the bushes before I could think too much about the matter.

Coral snakes are very dangerous. They're in the same snake family as the cobras and mambas. Because of their small heads I've been told that corals can't bite anything larger than a finger. However, my new field guide says that they're able to gape their mouths so wide they can bite almost any part of the human body where the skin is loose enough to be even slightly pinched so it can be held in a bite. Now when I go out jogging before sunrise my ankles tingle in anticipation...

One more note: Our Variable Coral species, different from the Central American Coral which doesn't occur here, but possibly the same as the Mayan Coral Snake found to the southeast, is truly variable. The greatest variation is in the numbers, and therefore the widths, of its colored bands. Variable Corals in northern Guatemala south of here may have as many as 50 black bands, but here in the northern Yucatan they may have as few as 12, the red bands expanding at while the other bands remain small. In fact, the snake I saw Monday basically looked like a red snake with widely spaced black bands. I didn't have the presence of mind to count his black bands but surely there were no more than 12, and my impression was that there were fewer.

You can see a Variable Coral Snake at the bottom (a False Coral at the top, one we don't have here) at http://www.fathom.com/feature/122594/3522_snake9_LG.html.

*****

SEVEN TURQUOISE-BROWED MOTMOTS
The other day a tourist visiting the hacienda asked me if the northern Yucatan had any birds as spectacular as the toucans and macaws he'd seen in Guatemala. I replied that our motmots surely were as colorful and exotic, if not quite as large.

Motmots are members of a family of birds restricted to the New World tropics -- they're "neotropical." Taxonomically placed near the Kingfisher Family, they have fairly long, stout bills that curve downward slightly, weak feet, a general preference for forests and forest edges, they are colorful, and -- the most spectacular feature -- barbs inside the two longest tail feathers are absent, so part of the feathers consists of nothing but the naked shafts (the feathers' "midribs"). I've read both that the missing barbs fall out by themselves, and that the bird removes them, and I don't know which is the case.

Ever since I got here in October one or more motmots has been hanging around right outside my door. The species is the Turquoise-browed Motmot, which could hardly be more colorful. Blues, greens blending to yellow, russets, black -- and those incredibly bright, bushy, turquoise eyebrows. You can see one here.

Rarely I've seen more than one, though lately two or three have begun showing up. Still, this week as I fixed breakfast I wasn't prepared when SEVEN suddenly landed on the wires passing over my campfire area, two or three of them issuing their throaty, hoarse, hollow t'k'wok t'k'wok t'k'wok calls, sounding a little like hoarse, very large whip-poor-wills. What an exhibition!

I read that this species nests singly or in colonies of a hundred or more pairs, so maybe my seven motmots on a wire is nothing compared to what can be seen. Still, those seven provided my birding highlight for this week.

*****

SLUGS, SNAILS & MU
Surprisingly often I receive mail from people I don't know, who don't introduce themselves, and who, without explaining the circumstances, ask me the most curious questions. The other day Ted Campbell of somewhere in Cyberspace sent an email consisting of one line:

"Can you tell me what if any good the slug or snail does."

Well, it's not a bad question to chew on.

For, the whole concept of creatures doing either good or bad invites further questions. Particularly, "What is good?" and "Good for whom?"

"Good for whom?" is the easiest to deal with because I can guess that Ted wants his answer in terms of "good for humanity," or "good for the ecosystem."

I won't touch the question of how an animal might be "good for humanity" because it smells too much of the religious concept that Nature has been created to serve mankind. Because of destructive, unsustainable human behavior encouraged by that notion, I regard it as the most dangerous element of our western, desert- originated religions.

Neither does asking whether an organism is "good for the ecosystem" strike me as appropriate. A prime feature of the Earth-ecosystem -- the biosphere -- is that all its components are interconnected and its living things are mutually dependent. Science is just beginning to grasp how intricate, fragile and necessary these connections are. Therefore, in my opinion, no human is in the position to judge how any living thing is good or bad for the ecosystem. Moreover, we don't know the ultimate destiny of our evolving biosphere, so how can we judge whether the role something plays in it now is "good" or "bad"?

Somewhere, a long time ago, I think I read that the ancient Chinese had a special reply for any question asked from an invalid premise. The reply was "Mu." "What did they say when the blue sky hatched from its egg?" The best answer, shaking your head, is "Mu." "Of what good is a slug to the ecosystem?" "Mu."

So, "What is 'good'?"

"Goodness" and "badness" can be judged only from specific frames of reference. If your frame of reference is living pleasurably without regard for the future, then a thorn in the foot is bad and a stick of chocolate is good. If your frame of reference is the Christian Bible, then my owning a Kentuckian as a slave is bad, but enslaving a Canadian is OK, as explained in Leviticus 25:44.

But, I don't know why the Universal Creative Force created the Universe in the first place, why She keeps it going in such mysterious ways, and what it all means. Consequently, my frame of reference just isn't broad enough for making value judgments about any part of Her Creation, including Her slugs and snails.

Therefore, Ted Campbell someplace out there in Cyberspace, "Mu" to you.

*****

Best wishes to all Newsletter subscribers,

Jim

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