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

January 18, 2015

OYSTERCATCHER
Sometimes the mudflats are covered with hundreds or even thousands of sandpipers, plovers, skimmers, gulls, terns and the like, but you'll be lucky if there's a single American Oystercatcher, HAEMATOPUS PALLIATUS, among them. But, if there is one, it'll be easy to see, and you can see why at http://www.backyardnature.net/n/15/150118oc.jpg.

The bird's big, heavy beak is used not only to stab into submerged mud looking for food, but also to pry open oysters, clams, mussels and other bivalve mollusks. It also eats sea urchins, starfish, crabs, worms and other marine invertebrates.

The Oystercatcher has a special way of dealing with the hard shells of bivalve mollusks like oysters, clams and mussels. It looks for feeding individuals with their shells cracked open. The bird jabs its bill into the open shell and tries to sever the strong muscle that clamps the shells shut. This technique works well enough, but sometimes there's a problem, especially when the mollusk is a big one firmly rooted in its substrate. Then the bivalve may clamp its shell on the bill and hold the bird in place until the tide comes in, drowning it. Oystercatchers also feed by carrying loose shellfish out of the water and hammering at their shells. Another approach is to probe for buried soft-shell or razor clams whose shells are softer.

Visitors always ask if the Oystercatchers eyes really are as large as they seem. Most of the apparent size consists of a red ring around the orange eye. In our picture you can barely see the orange eye centered in the large, red eye ring.

American Oystercatchers are found along American coasts from southern California to central Chile on the Pacific side, and from New England to Brazil on the Atlantic side. In the 19th century they became locally extinct in the US Northeast due to hunting and egg collecting. After receiving protection under the Migratory Bird Treaty Act, their range extended northward to reoccupy areas they'd disappeared from.

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EURASIAN COLLARD DOVES IN MEXICO
Back in arid southwestern Texas I was surprised to find Eurasian Collard Doves, STREPTOPELIA DECAOCTO, firmly established along the Dry Frio River. Now I've been surprised again to find them well established here in Río Lagartos on the Yucatan's northern coast. You can see one taking his daily morning stroll on the pavement outside my door at http://www.backyardnature.net/n/15/150118dv.jpg.

Those who have been paying attention to the amazingly fast spread of Eurasian Collard Doves in the Americas won't find this at all surprising.

They were documented in Yucatán state as early as 2010, and even earlier in other Mexican states; By 2006 they'd been documented in Sinaloa, Oaxaca, Jalisco, Veracruz and other states. A study in Yucatán state in 2011 found them mostly in the northwestern corner of the state, with none reported from the Río Lagartos area.

Other non-native birds that can be seen nowadays in Yucatán state include Pigeons, Starlings, House Sparrows and the Tricolor Munia, the latter similar to a grosbeak.

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YOUNG FLAMINGOS PREENING
On Thursday morning the tide was low, the sun warm and the wind hardly stirring. It was a good time for adolescent flamingos to huddle close together the way self-conscious teenagers often do, and preen. You can see this prettily done at http://www.backyardnature.net/n/15/150118fl.jpg.

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FRIGATEBIRDS DRYING THEIR WINGS
On the same sun-filled morning, Magnificent Frigatebirds adorned themselves on a snag, preening and spreading their long, slender wings against the sun, as shown at http://www.backyardnature.net/n/15/150118fb.jpg.

Those with white heads and chests are immatures, while the ones with all-black heads and chests are males. Adult females have black heads and throats but white chests.

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SALTPAN FIDDLER CRAB
Up the estuary at the salt pans of Las Coloradas our flamingo-watching boat pulled up to a levee separating one of the ponds from the estuary, so guests could see the ponds' water, bright pink from algae, and marvel at the size of the operation. Stepping ashore onto sand composed of shell fragments, numerous tiny critters skittered from beneath my incoming foot, and I wondered what they might be. They ranged from pea-size to ant-size. A picture of a well camouflaged pea-size one with its big, white "fiddling" claw in the upper, right corner is shown at http://www.backyardnature.net/n/15/150118cb.jpg.

With such an oversized claw, clearly we had a fiddler crab, and all fiddler crabs belong to the genus Uca. However, about a hundred fiddler crab species are recognized worldwide, so how could I hope to identify this one? Happily, on the Internet, help came by way of a 1987 study by Carl Thurman II, published in Crustaceana Vol. 53, No. 1, entitled "Fiddler Crabs (Genus Uca) of Eastern Mexico (Decapoda, Brachyura, Ocypodidae)."

That study lists seven fiddler crab species on the coasts of the Yucatan Peninsula, of which only five occur here on the northern coast. Pictures of all five of those species were summoned on the Internet, and of those only one matched our image, and that was the appropriately named Saltpan or Burger's Fiddler Crab, UCA BURGERSI.

The main field marks separating the Saltpan Fiddler Crab from the other species -- apart from it being found among the salt pans -- are that its top shell, or carapace, bulges forward to between the eyes, while on other species that area is flattish. Also, the carapace's speckles, the banded legs, its small size (barely 20mm, or less than an inch), and remarks from various sources that Burger's Fiddler Crab is common in a variety of habitats in the Yucatan all support the ID.

Saltpan Fiddlers occur throughout the Caribbean from coastal Florida south to South America. Their habitat is described as estuarine beaches, usually near mangroves, living in burrows constructed in the intertidal zone. They are "detritivores," meaning that they feed on detritus, which is non-living particles of organic matter in the sand, mud and washed-up material at the water's edge.

James Lazell's 2005 book Island: Fact and Theory in Nature, describing the flora and fauna of Guana Island in the British Virgin Islands, describes Saltpan Fiddlers as fairly swarming on mud around a salt pond, just like those on the shore of salt ponds at Las Coloradas. He also writes that the larvae of these crabs are a mainstay of the flamingo flock" which probably was the case at Las Coloradas, too, where flamingos were foraging with their heads beneath the water not far away.

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TOMTATE GRUNT FISH
Nearly always when we pass up the estuary to the flamingo feeding grounds, fishermen on a little pier beneath the bridge of the coastal road between Río Lagartos and Las Coloradas are fishing with cast nets. Sometimes our tour guide asks for any throwaways the fishermen might have on hand, for these unwanted fish can be tossed into the water to attract fish-eating raptors or crocodiles for picture taking. That's how I got the picture of the six-inch long (15cm) fish seen lying on the boat's bottom at http://www.backyardnature.net/n/15/150118gt.jpg.

Several local species look more or less like this, so during the identification process attention had to be paid not only to the fish's general shape, coloration, and fin arrangement, but also to such details as the number of spines in the top, or dorsal, fin, the back, lower fin, which is the anal fin. Once I'd figured out the fish's family, pictures of each species on the list of fish identified in Ría Lagartos Biosphere Reserve were sought on the Internet.

Eventually I settled on the name HAEMULON AUROLINEATUM, usually known as the Tomtate. It's one of several species known as grunts so sometimes it's listed as the Tomtate Grunt. They're called grunts because of the sound made when caught. The sound is made when the fish grinds its pharyngeal teeth, which are teeth in the throats of a number of fish types. Paco, our guide that day, called the fish a Ronco, in Spanish meaning "hoarse," which describes the grinding sound amplified by the air bladder, which acts as a resonator. Maybe the sound's purpose is to surprise a captor enough to drop its catch. The origin of the word "tomtate" seems to be unknown, though it's supposed to be an Americanism.

Tomtates are fish of the western Atlantic, found in seagrass beds, sand flats and patchy reefs from Massachusetts south to the Brazilian coast. Tomtates feed on small crustaceans and other invertebrates, mollusks and plankton. They are not highly regarded by fishermen, but in some places they're marketed both fresh and salted.

Adult Tomtates during breeding season display bright, yellow lines, with an especially bold yellow line through the eye and all the way back to the tail, plus in some stages there's a conspicuous, dark smudge at the base of the tail. However, pictures on the Internet show fish as pale and void of bright, yellow lines and patches as ours. More important for identification are details of fin configuration. The FishBase.Org website reckons the Tomtate's dorsal fin to have 13 spines at the front and15 soft rays at the back, with the anal fin having 3 spines at the front and 9 soft rays at the back.

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BUCCANEER PALM
Along the coast not far from Río Lagartos, if you climb atop a certain sand dune maybe a hundred feet (30m) inland and look inland, you'll see a wild, windswept, sun drenched flatland mantled with scrubby, low vegetation largely not over waist high, but here and there with palms of various sorts rising above everything. You can see such a view at http://www.backyardnature.net/n/15/150118pl.jpg.

In that view the low palms in the foreground are Chit Palms, Thrinax radiata; the large-leafed plants forming a low thicket at the picture's center-right are Sea-grapes, Coccoloba uvifera; tall, very slender spikes rising above everything here and there are flowering stems of Caribbean Agaves, Agave angustifolia, and; on the horizon you can see widely scattered palms looking like upside-down feather dusters.

The feather dusters are Buccaneer Palms, sometimes also called Cherry Palms or Sargent's Cherry Palms. They're PSEUDOPHOENIX SARGENTII, and stand maybe 15 feet tall (4.5m). A closer look at a Buccaneer Palm rising from an impenetrable thicket of Chit palms and Caribbean Agaves is at http://www.backyardnature.net/n/15/150118pm.jpg.

You can see that Buccaneer Palms are very handsome and worthy of being planted. A lot of people have thought that for a long time, and that's the prime reason, along with habitat destruction, that so few remain in the wild. Throughout their distribution from the Yucatan's northern and eastern coasts, Cuba, southern Florida, the Bahamas and Hispaniola, the species has been dug up and hacked down for so long that nowadays a view of them such as ours is hard to find.

However, so many of their numbers have made it into the gardening business that in warmer areas they're easy to buy. At a gardening forum on the Internet, "billowen" in Port Charlotte, FL writes, "I planted a six footer a little over a year ago, I got a good deal for $200.00. This tree could easily retail for $500.00."

And that's why I'm vague about the location of the individuals in my pictures.

Another picture, showing that the fronds are feather-like, not fan-like, and that the frond segments, or pinnae, arise from the midrib, or rachis projecting upward V-like, not downward, is at http://www.backyardnature.net/n/15/150118pn.jpg.

In that picture, below the fronds and in the picture's center, you can see a small,   whitish, stalked, fruiting cluster from which the fruits have fallen. The configurations of the flower clusters and pinnae are important field marks, though in our area the palm's general form and habitat are so distinctive that you don't need to look closely to know you have a Buccaneer Palm.

In Florida they're trying to reintroduce Buccaneer Palms. Earlier, in one of their prime locations, "... the interior of Elliott Key was bulldozed by spiteful developers just prior to federal purchase of the island for the formation of Biscayne National Park." You can read more about this and about efforts to reestablish the species at http://www.palms.org/principes/1995/sargentii.htm.

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PALO DE CAJA
On the trail into El Zapotal, the isolated reserve maintained by the Mexican environmental Group Pronatura, in extreme northeastern Yucatán State, a bush with slender, arching stems was laden with maturing fruit and I couldn't place it. It's shown at http://www.backyardnature.net/n/15/150118al.jpg.

I've seen such small, red-ripening, succulent fruits arranged in panicles on wooden stems before, but notice that this plant's leaves are composed of three leaflets arising from atop a stiff petiole -- they're "trifoliate," like clover leaves. In my mind, such fruits in panicles on woody plants just don't go together with trifoliate leaves. Only a handful of woody plants bear trifoliate leaves. The fruits look like those of the Nightshade Family, so one was squished to see if it contained several tomato-like seeds, which it didn't, as seen at http://www.backyardnature.net/n/15/150118am.jpg.

It was a drupe with a single, hard seed, like a cherry. Cherry trees are members of the Rose Family, but the Rose Family is mostly of the Temperate Zone, and not a single Rose Family member is listed for the Yucatan. After a good deal of cogitating the closest I could come to such a plant was the Brazilian Pepper Tree, Schinus molle, which produces similarly small, red, spherical, drupe-type fruits in panicles on woody stems. However, that tree's leaves are compound, not trifoliate.

Still, making that association helped me focus on the part of the Phylogenetic Tree of Life where such plants reside. Brazilian Pepper Trees belong to the Cashew/Poison Ivy Family, the Anacardiaceae, but nothing in that family occurring in the Yucatan looked like our plant. Browsing nearby branches of the Tree and discarding those with only Temperate Zone species, soon I came to the Soapberry Family, the Sapindaceae, a big tropical family of mostly woody plants, often climbing, and leaves mostly compound, including trifoliately compound ones. Looking on the Internet at species in that family occurring in the Yucatan, it wasn't long until a good match came up: the genus Allophylus.

We have two look-alike Allophylus species, and after a lot of image comparisons I'm pretty sure that ours is the one more commonly found in the Yucatan, ALLOPHYLLUS COMINIA. In Spanish it's often called Palo de Caja, more or less meaning Box Bush. ,

Palo de Caja is distributed from southern Mexico south through Costa Rica and in the Caribbean area. Cuba's Agricultural Ministry claims that extracts from Palo de Caja can be used to control diabetes by diminishing glucose levels, plus they are antioxidant and anti-inflammatory.

You can imagine that birds relish the succulent flesh. In our picture, many fruits appear to have been removed as they matured.

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BRAVAISIA
Across the estuary from Río Lagartos, along the almost flat shore of the canal cutting through the slender finger of land separating the estuary from the Gulf of Mexico, for the first fifteen or so feet (4m) there's just mud and sand, either bare or carpeted with grass and other knee-high vegetation, until suddenly there's a dense, green wall of vegetation rising about ten feet high (3m). The mostly woody plants composing the wall are so intimately entangled that it's hard to make out individual plants. However, this week one plant is issuing white, inch-broad flowers (3cm) that stand out against the dark green background, as shown at http://www.backyardnature.net/n/15/150118bv.jpg.

You can see that the plant's simple leaves with entire margins (no lobes or teeth) arise two per node (opposite) and that flower clusters appear at stem tips. A closer look at a flower showing its slightly asymmetric form and enlarged, purple-splotched lower lobe is at http://www.backyardnature.net/n/15/150118bw.jpg.

A peep into the corolla's throat showing how nicely it's adapted for pollinators such as bees is at http://www.backyardnature.net/n/15/150118bx.jpg.

There you can visualize a bee alighting on the corolla's big lower lobe, then following the yellowish nectar guide down into the corolla tube, in the process leaving pollen from other flowers on the slender, stigma-tipped style dangling across the tube's entrance, while gathering new pollen from the two anthers looking like little white bananas held at the tube's ceiling.

All these features, especially the opposite leaves and the slightly asymmetrical corolla with only two anthers, lead us to the big, mostly tropical Acanthus Family, the Acanthaceae. Knowing that, it was easy to figure out that our canal-side plant was BRAVAISIA BERLANDIERIANA, for which no English name can be found. The genus Bravaisia is a small one of only three recognized species, all of which occur in southeastern Mexico and northern Central America.

Though it was hard to say whether our plant was woody or herbaceous, Thomas Daniel's 1987 revision of the genus Bravaisia says that it's a shrub or small tree up to 25 feet tall (7.5m). A number of habitats are described for it, all developed on wet silt and/or sand.

Also Daniels reports that in the Yucatan traditionally Bravaisia berlandieriana has been used medicinally for the treatment of mammary abscesses.

Otherwise there's little known about this species. It's one of those little-known, low-profile plants with such pretty flowers and foliage you'd think anyone would be happy to grow it right outside the door.

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STENOCEREUS ORGANPIPE CACTUS IN THE WOODS
In dense woods a few miles inland I thought I'd found a new-for-me cactus species when the 20-ft-tall (6m) organpipe-type individual turned up shown at http://www.backyardnature.net/n/15/150118st.jpg.

I'd certainly never encountered such a tall cactus in this area, so I set about "doing the botany." You can see how thick the stems are relative to my hand at http://www.backyardnature.net/n/15/150118su.jpg.

A cluster of spines arising from a hairy mound -- the areole -- atop one of the cactus's stem ridges is shown at http://www.backyardnature.net/n/15/150118sv.jpg.

A view from below emphasizing a stem's "wings" is at http://www.backyardnature.net/n/15/150118sw.jpg.

The cactus's base, white with lichens and scar tissue, is at http://www.backyardnature.net/n/15/150118sx.jpg.

But, it wasn't a new-to-me species. Already we've seen it, and it's profiled at http://www.backyardnature.net/yucatan/stenocer.htm.

It's the rare Stenocereus laevigatus. Other individuals I've seen of the species looked different because they were in full sunlight and not competing with surrounding tall trees. Previously seen individuals were shorter, more widely spreading, and the "wings"on their stems were much thicker, presumably fuller of water.

But, this is a good lesson on how one species can differ in its appearance, depending on its habitat.

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SEASIDE OXEYE
A roadside through the salt flats was prettily fringed with yellow flowered, knee high, goldenrod-like Yellowtop, Flaveria linearis. Here and there a little farther off the road, at the edge of ground too wet and salty for regular plants to grow on, stood a much-branched, belly-high, halfway scraggly looking shrub with thick, semi-succulent, whitish stems and small, succulent leaves arranged two per stem node (opposite), as shown at http://www.backyardnature.net/n/15/150118bo.jpg.

With such succulent leaves and rubbery stems the bush was obviously a halophyte adapted for salty soil, which was interesting, but even more interesting was that it was a member of the big Composite or Daisy Family, the Asteraceae, which contains only a few halophytic species. You can see one of the shrub's typical daisy-type flowering heads framed by sharp-tipped, succulent leaves at http://www.backyardnature.net/n/15/150118bp.jpg.

When identifying members of the Composite Family it's always worth paying attention to the scale-like bracts forming the bowl-shaped "involucre" below the flowering head, for bracts come in endless shapes, colors, textures and configurations. This succulent bush's round-tipped bracts were appropriately and strangely succulent, absolutely bloated with juicy, salty tissue, as shown at http://www.backyardnature.net/n/15/150118bq.jpg.

Breaking open a flowering head to see what kind of "pappus" arose atop the future fruits, if any, I found that instead of the usual hairs or scales the pappus was a kind of irregular cup or crown surrounding the base of the corolla tube, as shown at http://www.backyardnature.net/n/15/150118br.jpg.

Some of the bush's flowering heads already had matured and were producing fruits. You can see some mature, cypsela-type fruits with their pappi dried up but persisting atop them at http://www.backyardnature.net/n/15/150118bs.jpg.

With so many unusual features, this shrub was easy to identify to genus level. It was a Borrichia, a small genus of only three species, with all species limited to only the US, Mexico and the Caribbean area. The three species are similar looking, but the involucres of only one have round-tipped bracts like those in our photo, as opposed to sharp or spine tipped one, and that's BORRICHIA ARBORESCENS.

Borrichia arborescens occurs in the Florida Keys, Bermuda and the Caribbean area, and here and there on shores of the Gulf of Mexico. With such pretty flowers it enjoys many names, a real mishmash of them, including Silver Sea Oxeye, Tall Sea Oxeye, Tree Seaside Tansy, Tree Seaside Oxeye, Seaside Tansy and Seaside Oxeye. In the Yucatan it's called Margarita de Mar, or Ocean Marigold.

The shrub is pretty enough to be planted occasionally in tropical gardens, where it often serves as a hedge or ground cover. Its succulent leaves are salty tasting but a little bitter with too much of a resiny taste to want to eat many. A few dropped into a salad might be nice, though.

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FEATURED ESSAYS FROM THE PAST:

"Sustainable Rock & Roll" from the May 23, 2004 Newsletter, at http://www.backyardnature.net/n/p/040523.htm

"The Bite" from the March 17, 2008 Newsletter, at http://www.backyardnature.net/n/p/080317b.htm

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Best wishes to all Newsletter readers,

Jim

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