JIM CONRAD'S
NATURALIST NEWSLETTER
Issued in Río Lagartos, on the northern coast of
Yucatán, MÉXICO
in Ría Lagartos Biosphere Reserve

November 30, 2014

BLACK SKIMMERS
On a long, narrow sandbank rising just out of the water a few miles up the estuary toward Las Coloradas, on most days there's a noisy crush of lounging waterbirds, especially gulls, terns, sandpipers, pelicans and, more than anything, Black Skimmers. A small part of the skimmers is shown at http://www.backyardnature.net/n/14/141130sk.jpg.

Black Skimmers, RYNCHOPS NIGER, are black-backed birds seen offshore southward from New York and California, flying very low over the water with the lower mandible of their beaks slicing through the water, scooping up small fish, insects, crustaceans and mollusks. I read that they are more likely to skim at dawn, dusk and even at night, and seeing how much daylight time they spend loafing on that sandbank, I suspect that that's right.

In our picture notice that the lower mandible of the Black Skimmer's beak is substantially longer and stouter than the upper one. In fact, according to the Audubon Society, among all birds, only the three skimmer species constituting the Skimmer Family possess beaks with the lower mandible longer than the upper one. Their amazing beak is enough for the three species to be grouped into their own family, but not enough to get them their own bird order. They belong to the Shorebird/ Gull Order, the Charadriformes,along with gulls, sandpipers, plovers and the like.

Black Skimmers occur all along Mexico's Pacific and Atlantic coasts to South America, where they can be seen on big rivers and lakes of most of the continent.

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PEREGRINE FALCON
I've always regarded Peregrine Falcons, FALCO PEREGRINUS, as rare, and it's true that they were virtually eradicated from eastern North America by pesticide poisoning, especially from the use of DDT, in the middle 20th century. But a major conservation effort was made and now in many large cities and coastal areas they're regularly seen. Most trips I make up the estuary here I see one or more, and one is shown about to take flight at http://www.backyardnature.net/n/14/141130pg.jpg.

You know you have a Peregrine Falcon when it's a big, heavily built falcon with a dark cap and streak below the eye -- a "mustache." They're very distinctive looking birds but sometimes people confuse them with the much more common Kestrel, because of the similar shape and facial pattern, both with mustaches. The little Kestrel is only 8.5 inches long (22cm), while the Peregrine is nearly twice as long, 15 inches (38cm), but in the field sometimes it's hard to judge size. Kestrels show a rusty back, but there's no rustiness on the Peregrine.

Peregrines hunt almost exclusively medium-sized birds such as pigeons and doves, waterfowl, songbirds, and waders, but they're also known as killing the largest diversity of birds of any other North American raptor -- with over 300 bird species having been documented as Peregrine prey, including nearly 100 kinds of shorebird.

Peregrine Falcons are one of a few birds with an essentially worldwide distribution, though they're still absent from large parts of their former area. Having such an enormous distribution, their population is evolving into subspecies, each subspecies with adaptations for their own part of the world. Nowadays 19 subspecies are recognized.

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FLAMINGOS FEEDING
Flamingos don't peck at their food or capture small prey to gobble down like most birds, but are "filter feeders." In that respect they're more like whales and oysters than the vast majority of other birds. When they feed in their preferred environments, typically they have their heads upside-down, under the water, as seen at http://www.backyardnature.net/n/14/141130fl.jpg.

In this position they take in water in which tiny brine shrimp and blue-green algae are suspended. These animals are filtered out with the help of many complex rows of horny plates lining the beak inside. That's the same food-straining process used by baleen whales. In order for the beak to work "normally" on a head being held upside-down, the flamingo's upper jaw is not rigidly fixed to the skull the way it is in most other animals. This means that as the bird feeds, the upper bill -- which is the lower bill on an upside-down head -- moves up and down just like a human's lower jaw.

The filtering process is helped by the flamingo swinging its head back and forth and letting the water flow through the bill. As this happens, the tongue pumps water through the bill's strainer by quickly moving back and forth in its groove, sucking water in when it pulls back, and expelling water when it pushes forward. This motion is repeated up to four times a second.

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TREE CALLED CHICKEN MEDICINE
In this area especially in dry soil where trees are returning to cleared forest areas and savannas there's a much-branched, small tree that now at the end of the rainy season already is losing its leaves, except for a few small ones at branch tips. Its many slender stems are whitish, emphasizing the intricacy of the tree's maze of branches, as shown at http://www.backyardnature.net/n/14/141130ep.jpg.

A close-up of the tree's multiple white trunks splotched with yellow lichen can be seen at http://www.backyardnature.net/n/14/141130ev.jpg.

The tree's simple leaves aren't much longer than an inch (3cm), and the ones presently on new sprouts are even smaller, as shown at http://www.backyardnature.net/n/14/141130eq.jpg.

If you break one of those leaves apart, white latex emerges from its veins, as seen at http://www.backyardnature.net/n/14/141130eu.jpg.

The leaf shape and texture, and this white latex, suggest that our little tree belongs to the big, mostly tropical Euphorbia or Spurge Family, the Euphorbiaceae. However, we have lots of species in this family here, so that's not much help. What's needed for a good identification is flowers and fruits, but normally trees at the end of their leaf-dropping time don't bear flowers and fruits. But, this little tree does. You can see a cluster of tiny, branch-tip flowers in various stages of development at http://www.backyardnature.net/n/14/141130er.jpg.

A close-up of a flower showing an important feature is at http://www.backyardnature.net/n/14/141130es.jpg.

This picture shows a female flower being held outside a cup-like structure. The unisexual flower consists of nothing but a three-lobed ovary topped by three white style-arms with purplish stigmatic areas where pollen grains from male flowers are supposed to land and germinated. Once the female flower is pollinated, its pedicel greatly enlarges and the ovary swells into a brown, three-parted, capsular fruit, as shown at http://www.backyardnature.net/n/14/141130et.jpg.

Though we've never seen anything exactly like this, many times in this Newsletter we've encountered this identical basic flower structure.

First, the bowl-like structures on stems looking like flowers are actually "cyathia" inside which reside one or more male flowers consisting of no more than one stamen. And amidst these stripped-down male flowers a stem, or pedicel, arises, atop which -- held outside the cyathium -- there's a three-lobed ovary topped with three styles with dark stigmas at their tips.

These are the diagnostic features of a group of plants known as spurges, the genus Euphorbia, in the big Spurge Family, which embraces about 300 genera. By now we well known that within the genus Euphorbia the variety of plant forms is mind boggling -- though basic flower structure remains the same throughout. There are tiny, weedy, herbaceous euphorbias, and those who might be mistaken for large, spiny cactuses; there are regular wildflowers, ornamental cultivars and, as we see now, regular trees.

Our tree euphorbia is EUPHORBIA SCHLECHTENDALII, which seems to have no English name, but in Spanish literature often is referred to as Medicina de las Gallinas, which means "Chicken Medicine." I find no relationship between the tree and chickens, but it's true that in Oaxaca its latex is dissolved in water and used for venereal diseases and chest pains resulting from indigestion, and in the Yucatán the macerated leaves have been used against dandruff.

"Chicken Medicine" occurs in hot, arid lowlands from central Mexico south to Costa Rica, mainly serving as a pioneer tree in rejuvenating forests.

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PORTIA TREE
Beside the tall, white wall surrounding Río Lagartos's cemetery there stands a well formed tree about 15ft tall (4.5m), with shiny, heart-shaped leaves about three inches long, and nowadays handsomely adorned with cup-shaped flowers also about three inches long, as shown at http://www.backyardnature.net/n/14/141130th.jpg.

A side-view of one of the pretty flowers appears at http://www.backyardnature.net/n/14/141130ti.jpg.

An interesting field mark to notice is that the smaller, outermost "petals" are actually calyx lobes, or sepals, modified to look like petals. One way you know they're not real petals is that their color and texture don't exactly match those of the corolla within the ring of lobes, but the main indication is that the lobes are weakly attached along a fracture line to an otherwise normal, green, bowl-shaped calyx below the petal-like lobes. If you break open a flower, you can see all this as well as other important features, as shown at http://www.backyardnature.net/n/14/141130tj.jpg.

All those stamens united at their bases into a cylinder surrounding the ovary's style, and with thick, yellowish stigmas atop a white style emerging from the stamen-bearing cylinder tells us instantly that here once again we're dealing with the huge Hibiscus or Mallow Family, the Malvaceae. However, the calyx with its petal-like sepals that easily break off the green bottom suggest that the tree isn't a hibiscus itself, and the rounded, leathery-skinned fruits are very unlike hibiscus fruits. You can see the fruits, which don't split open at maturity, and appear adapted for dispersing its seeds by dropping into water and floating away, at http://www.backyardnature.net/n/14/141130tk.jpg.

With such an un-hibiscus-looking fruit it was easy to identify our cemetery tree as what's often called the Portia Tree. It's THESPESIA POPULNEA, so generally planted and often escaped into the wild in tropical regions worldwide that it's unclear where it originated, though some suggest India. It's common in coastal strand vegetation throughout the Old World tropics and has escaped in much of tropical America, including southern Florida where it's regarded as an invasive. It must grow wild here, too, because it's listed in the inventory of plants of the Ría Lagartos Biosphere Reserve.

Something I learned only by reading about it is that when its flowers open they are yellow, only turning pinkish like those in our pictures after they are pollinated. The Tree Cotton we grew back at Chichén Itzá did the same thing. In fact, Portia Tree is very closely related to the cotton plant

One reason the Portia Tree is planted so widely is because it's pretty. Another is that it's useful. Its wood is excellent for making small articles such as musical instruments, is multicolored and resistant to termites, rope can be made from its fibrous bark, yellow dye can be extracted from its flowers and fruits, plus Portia Trees provide good shade and make a fine windbreak. The flower buds and leaves can be eaten raw or cooked. Medicinally, the seeds are applied to scabies and other skin diseases, and are rubbed onto swollen joints, and a tonic is brewed from its roots. Yellowish juice from young fruits is used to treat insect bites, gonorrhea, ringworm, and migraine headache. In fact, so many medicinal uses are listed for it that you just wonder about it.

Becoming introduced to such a tree for the first time is a genuine pleasure. Maybe I can help you share in my feeling of discovering something worthy by including an evocative picture of the entrance to the cemetery beside which our Portia Tree was standing, at http://www.backyardnature.net/n/14/141130xx.jpg.

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CARIBBEAN AGAVE FLOWERING
At Chichén Itzá we saw our local wild agave fruiting and sending up a sprout to flower later on, but somehow we missed the actual flowering. Here in the scrub vegetation on dunes along the coast and in thin soil atop limestone farther inland the agaves are abundant, and many are flowering. You can see how thickly they grow in a picture taken across coastal strand vegetation toward a ship loading salt at Las Coloradas about 20kms east of Río Lagartos at http://www.backyardnature.net/n/14/141130ag.jpg.

Attention must be paid when you walk through that vegetation because the agave blades are tipped with hard, sharp spines, shown at http://www.backyardnature.net/n/14/141130ah.jpg.

Even the blades' margins can rip your skin or clothing, as is clear at http://www.backyardnature.net/n/14/141130ai.jpg.

The big panicles of flowers atop their well defended bases are more welcoming to air-borne pollinators, but to attain the nectar down inside the flowers the bats who pollinate them have to penetrate a cloud of long, stiff stamens and styles, as shown at http://www.backyardnature.net/n/14/141130aj.jpg.

It's generally said that agaves with panicle-type flower clusters growing in tropical arid zones depend on nectar-feeding bats for pollination, while species in the temperate zone are pollinated by diurnal and nocturnal insects and birds, so our bat-pollinated species agrees with that notion. Each flower produces six stamens composed of slender, stiff filaments topped with curving anthers attached at their backs. Amidst each stamen cluster there's a short, thick style tipped with a roundish stigma, where bats are supposed to deposit pollen from other flowers. These details can be seen at http://www.backyardnature.net/n/14/141130ak.jpg.

This is AGAVE ANGUSTIFOLIA, often known as the Caribbean Agave, distributed from Costa Rica north to arid regions of northeastern Mexico, including all of the Yucatan. In Mexico the species is famous as the usual source of commercial mescal, mescal being Mexico's main traditional booze. Sometimes other agave species are used for mescal as well. Mescal is different from Tequila. Tequila is distilled mainly from the juice of a different species, Agave tequilana, and is generally regarded as more upscale than mescal.

Our Caribbean Agave has been cultivated for so long that several important cultivars have been developed, including some that are important sources of fiber -- though most commercial agave fiber comes from yet another species, Agave sisalana. Numerous ornamental cultivars of the Caribbean Agave are planted throughout the world, including 'Marginata' with white blade margins and a particularly pale form often called Agave angustifolia Woodrowii.

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MARSILEA THE AQUATIC FERN
Alongside the little road between Río Lagartos and San Felipe there are several shallow ponds and in one grew what can only be described as a lot of four-leaf clovers with submerged stems and roots, only their leaves floating at the water's surface. You can see this at http://www.backyardnature.net/n/14/141130ma.jpg.

Of course clovers don't grow like this, and I'd seen such a thing before so I knew it wasn't clover despite first impressions. Wading into the water I uprooted a cluster of leaf stems and stretched them out on the water's surface to see how long the stems were. This is shown at http://www.backyardnature.net/n/14/141130mb.jpg.

If I'd needed a hint as to what kind of plant this was, I'd have been told by what's shown at http://www.backyardnature.net/n/14/141130mc.jpg.

That looks just like a fern's fiddlehead -- the special form immature fern fronds take as they enlarge and unfurl. When something like a fern's frond is rolled coilwise from its top downward, it's said to be "circinate," and this was definitely a circinate fern frond unrolling. You might like to compare what's in the last picture with uncoiling fiddelheads of North America's Christmas Fern, shown at http://www.backyardnature.net/n/09/090302cf.jpg.

So, when you see an aquatic "clover" with its leaves floating on the water's surface, think of the truly aquatic fern genus Marsilea. Ferns in that genus often are called Water Clovers, despite having nothing to do with clovers other than looking like them.

Seven Marsilea species are listed for Mexico, of which only one is known to occur in the Yucatán, and that's MARSILEA VESTITA, so I'm assuming that that's what we have. However, the online Flora of North America asserts that "Species identification is virtually impossible without fertile material," so I can't be sure. I looked for the small reproductive structures, known as sporocarps, but could find none. The floating leaflets do display slender markings on their undersides, almost like spore-producing "sori" of spleenwort ferns, but these were just streaks having nothing to do with reproduction, and I can't find anything about their purpose, if there is any. The streaks are shown at http://www.backyardnature.net/n/14/141130md.jpg.

Marsilea vestita is often known as Hairy Water Clover and is distributed throughout most of the western US and adjacent western Canada, south through Mexico, plus in Perú in South America.

Sometimes Hairy Water Clover is sold in gardening stores as an attractive addition to backyard goldfish or lily ponds.

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DEAD MAN'S FINGERS ALGA
On the barrier island across the estuary from Río Lagartos, on the sandy, wave-washed beach facing the Gulf of Mexico and beside the canal connecting the Gulf with the estuary, a hand-sized clump of algae washed ashore looking like a tangle of green, forked spaghetti. You can see it at http://www.backyardnature.net/n/14/141130co.jpg.

A closer look revealed no outstanding features, no distinct nodes or reproductive structures, just occasionally branching, cylindrical stems that felt spongy and rubbery. One rather subtle feature that helped with identification was that where the stems branched, the stem below the branching was slightly flattened. You can see this at http://www.backyardnature.net/n/14/141130cp.jpg.

This is one of a group of species of green algae of the genus Codium, of which about 50 species are recognized, called Dead Man's Fingers. When the tide is out and they hang limply from rocks they're attached to, that's when they look like lifeless, green fingers.

Our particular Dead Man's Fingers, sometimes also called Green Fleece and other names, is CODIUM DECORTICATUM. It occurs worldwide, from equatorial regions to the polar zones, normally inhabiting shallow, muddy bays and harbors, so turning up near the canal leading to our shallow estuary is about right for it. It's easily dislodged, breaking into smaller pieces and disintegrating. Another Codium species, Codium fragile, also called Dead Man's Fingers, becomes invasive in certain areas, overwhelming local algal species and damaging oyster beds. However, our Codium decorticatum is better behaved, providing shelter for many small creatures, and food for certain sea slugs, snails and sea urchins.

In fact, people eat Dead Man's Fingers, too. Green Deane of Eat the Weeds fame writes that "Raw Codium has an earthy flavor, much like oysters, and is full of vitamins and fatty acids." He also says that in Hawaii it's eaten raw, often with tomatoes. It shouldn't be cooked or blanched because it becomes mushy and disintegrates from the heat. In Japan it's preserved in salt.

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OSLO BULK 9
In the above piece about the Caribbean Agave, Oslo Bulk 9 is the no-nonsense name of the ship taking on salt at Las Coloradas. In the original high-resolution picture the name was clearly visible. Once you have a ship's name you can look it up at a ship-spotting website such as the one at http://www.vesselfinder.com Just type the ship's name into the search box and hit enter.

That website and others describe Oslo Bulk 9 as a general cargo ship built in 2011 and weighing 5629 tons. It's 108m long (354ft) and 18m wide (59ft). Owned by Bulkship Management AS of Oslo, Norway, it currently sails under the flag of Singapore. After the picture was taken, at VesselFinder.Com, I tracked the ship as it left Las Coloradas, headed northward and within a couple of days docked in Morgan City, Louisiana. Then after another couple of days it was in the Gulf of Mexico again, its destination listed as back to Las Coloradas. The ship doesn't always shuttle between here and Morgan City; This year it's also been spotted in: Mobile, Alabama; Kingston, Jamaica; and Kaliningrad, Russia.

I'm told that much bulk salt exported from Las Coloradas goes onto icy streets up north. Despite all the salt leaving Las Coloradas by ship, on the road between Río Lagartos and Las Coloradas there's frequent traffic of big semis pulling double trailers filled with salt to be distributed throughout Mexico.

I'm fascinated by all these details and love to visualize Oslo Bulk 9 wandering the world's oceans, sometimes in Kingston, then in Kaliningrad, and now suddenly next to all those agaves on the beach at Las Coloradas, a sun-dazed little town of very modest, even hangdog-looking huts and houses on sand right beside the sea. I can imagine the ship sometime soon checking in with the office in Oslo, not knowing whether the next day it'll set sail to Maracaibo for a shipment of bananas, or Taiwan for a load of cheap steel, or maybe back south to Las Coloradas.

Where Oslo Bulk 9 goes all depends on how much is being paid for what, where, and the luck of the draw.

In other words, it's the same dynamic as in ecology. Money energizes the shipping industry the same way that Nature on Earth is fueled by solar energy. Money arrives at the home office and ships set sail, same as sunlight lands on photosynthesizing plants, energy is stored in carbohydrates, and eventually that energy, in one form or another, works its way up the ecological pyramid. We are all wandering ships competing for limited resources.

And both aboard ships at sea and among us organisms dealing with predator-prey relationships, transfer of energy, and evolution toward ever more sophisticated and efficient systems, there's this: The occasional individual human who for a moment lays down a wrench or mop, or steps away from the computer, and looks around, wonders about it all, shakes his or her head, and simply gets back to work.

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FEATURED ESSAYS FROM THE PAST:

"Honeybee Sting" from the July 25, 2004 Newsletter, at http://www.backyardnature.net/n/p/040725.htm

"A Handmade Burrow Saddle" from the July 13, 2007 Newsletter, at http://www.backyardnature.net/n/p/070713.htm

*****

Best wishes to all Newsletter readers,

Jim

All previous Newsletters are archived at http://www.backyardnature.net/n/.