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

October 26, 2014

HAWK LIKE A VULTURE
My first duty upon arriving at Río Lagartos was to accompany several local guides on a birding trip during which I helped them learn to say such things as "Look in that short bush with dark green leaves at the left of the big agave with its spike of white flowers."

This first outing was to a savanna next a marsh, so it was where two very different ecosystems met. It was a wonderful place for small seed-eating birds, and the raptors who preyed on the birds and rodents who fed on grass seeds and hid inside grass.

One of the raptors circling us, peering down into the grass that day, was the bird shown at http://www.backyardnature.net/n/14/141026zt.jpg  

But, raptors are birds of prey, mainly hawks and falcons, but with the blackish color, separate "fingers" at the ends of the wings, and its circling manner, what could this be other than a vulture? Yet, the head doesn't have a vulture's skinny neck, and vultures don't have banded tails like this bird. In fact, this is a hawk masquerading a vulture, the idea being that birds and rodents on the ground who might hide from a hawk or falcon may not scurry for cover when a harmless vulture passes overhead.

Our picture shows an immature Zone-tailed Hawk, BUTEO ALBONOTATUS, a species distributed from the southwestern US throughout Mexico and Central America, clear to southern Brazil. In Mexico it's a summer breeder in the north-central uplands, but here in the Yucatan it occurs only as a winter visitor.

And Zone-tailed Hawks are famous for mimicking vultures. They even soar with real vultures to add to the confusion.

Not far from where we saw the Zone-tail, we also saw a Crane Hawk, which similarly can be confused with vultures, though its long, bright-orange-red legs make it easier to recognize. Still, it's clear that out on the savanna if you look like a vulture you have a better chance to catch prey than if you're obviously a hawk. We also saw a Peregrine Falcon that day, who looks nothing like a vulture, but when you're as fast and powerful as a Peregrine you don't need to resort to subterfuge.

*****

SANDPIPERS IN WINTER PLUMAGE
Río Lagartos is situated a broad-based peninsula projecting into a lagoon behind a long, narrow barrier island. Where the town meets the water there are no sandy or muddy beaches, but rather a knee-high stone wall you can sit on with your feet almost touching the water. This is not a good place for shorebirds who forage along sandy beaches. Still, a few shorebirds typical of sandy beaches do turn up, sometimes landing on heaps of seaweed and uprooted sea grass windblown into heaps against the wall's base, or maybe they land on fishing boats tied up to the wall, or on wooden poles sticking from the water, maybe where old boardwalks once stood, or boats tied to. You can see one such bird at http://www.backyardnature.net/n/14/141026sp.jpg.

That's clearly some kind of sandpiper, but its plumage doesn't match that of any species in my field guide, either the winter or summer editions. That's a constant situation here at this time of year -- shorebirds, gulls, terns and the like all display various stages of in-between plumage, and very often are hard to figure out.

Focusing mainly on the dark chest, at first I thought our bird might be a Least Sandpiper, but it just wasn't right. In the end I had to get help from birding master Dave in Bermuda who, with many years experience with coastal birds, pegged it as a Spotted Sandpiper, a common species, and usually very easy to identify not only because of its spotted underparts but because when it walks it bobs its tail up and down almost continuously. Both of those features are missing in this bird, though a couple of pale spots do barely show up just beneath the wing.

After being away from the coast for several years it's taking me awhile to get all these shorebirds and gulls straight in my mind again. However it's a pleasure to do so.

*****

WHITE IBIS WITH A BROWNISH HEAD
One service I can provide to birders visiting the Yucatan during the northern winter is to illustrate birds in their transition and winter plumages, which often aren't well covered in field guides. You can see a White Ibis in the mangroves at the edge of town, a bird transitioning into its adult plumage, with a white body and brownish head and neck, at http://www.backyardnature.net/n/14/141026ib.jpg.

Two ibis species occur here, the other being the Glossy Ibis, all stages of which are dark, the adult being bronzy brown, and always with a blackish beak.

*****

CAVE SWALLOWS ON A WIRE
Eight species of swallows can be seen in our area, so when about fifteen birds turned up perched close together on an electrical wire running along the picturesque street next to Río Lagartos's seawall, the Malecón, I wondered who they might be. You can see a couple at http://www.backyardnature.net/n/14/141026sw.jpg.

An Important field mark to notice is that the birds' tails are only slightly notched, so they're not the Barn Swallows with deeply forked tails the visiting Northerner might expect. Also, despite the silhouetting caused by the bright background, an orangish color can be see on one birds throat, while the other bird displays similar orange color on the bottom near the tail.

These two features narrow down our possibilities to the Cliff and Cave Swallow. Some field guides show Cliff Swallows with squared tails and Cave Swallows with slightly notched ones, but Howell says that the tails of both of those species can range from squared to slightly cleft. The main difference Howell seems to find is that on the upper breast of the Cliff Swallow the orangish throat darkens at its base, strongly contrasting with the whitish underparts, while on Cave Swallows there's no such strong contrast.

Our birds don't seem to have a hint of that dark splotch below the orangish throat, the transition from throat to breast appearing gradual, so that's a vote for their being Cave Swallows. Another vote is that Cave Swallows are permanent residents here and I've often seen them here where they live in sinkholes, locally known as cenotes. However, Cliff Swallows only migrate through the area and I can't recall seeing them.

Still, even Howell admits that, especially in the Yucatan, juveniles of the two species can be confused.

*****

WILLET
A Willet, TRINGA SEMIPALMATA stalking along the muddy edges of the estuary at Río Lagartos is shown at http://www.backyardnature.net/n/14/141026wt.jpg.

Willets in winter plumage such as this, at least when they're not opening their wings displaying the broad, white bands running across their black inner wings, can be mistaken for the closely related Greater Yellowlegs in their winter plumage. However, yellowleg beaks are relatively longer and more slender, plus their beaks are all black, while you can see that our Willet's beak is two-toned -- blacker toward the tip.

During migration and the summer breeding season Willets turn up in most of western North America and along the coast in the East. In the Yucatan they're non-breeding winter visitors along the coast.

In the winter Willets occupy many wetland habitats, including freshwater and saltwater marshes, mudflats, and estuaries like ours. Mainly they eat invertebrates, including insects, aquatic worms, and mollusks, and even small fish. Our bird was probing the mud with its bill while walking along the water's edge.

*****

A YOUNG, WHITISH, BLACK IGUANA
Atop the low concrete storm wall separating one of Río Lagartos's backstreets from a mangrove swamp a lizard about a foot long was basking in the sun, as shown at http://www.backyardnature.net/n/14/141026ao.jpg.

A close-up of the head is at shown at http://www.backyardnature.net/n/14/141026an.jpg.

And a shot showing the whitish underside is at shown at http://www.backyardnature.net/n/14/141026ap.jpg.

The pale coloration and bold crossbanding didn't match any of the lizard pictures in Jonathan Campbell's Amphibians and Reptiles of Northern Guatemala, the Yucatán and Belize, but it most resembled what that book labeled Bourgeau's Anole, Norops bourgeaei. Since the book's publication the names have changed to White Anole, Anolis laeviventris.

However, something bothered me about this determination. First, there's a hint of green along our lizard's spine, not mentioned in descriptions of Anolis laeviventris. Also, our picture showing the lizard's chest reveals a definite fold extending across the chest from above each front leg. Anoles have skin flaps there that fan out longitudinally -- lengthwise -- not crosswise.

The short story is that I had to go on the Internet and confer with an anole expert, Jonathan Losos at Harvard, to be hit with the embarrassing but obvious truth that our lizard isn't an anole at all, but rather our abundant Black Iguana, which habitually perches atop rock walls just as ours is doing. How could this lizard have fooled me so?

Well, I just hadn't seen this particular stage of development in our Black Iguana, other immature Black Iguanas I've seen this size were green, and I guess I'm getting slow. When Black Iguanas are very young, they're green. As they mature they not only develop low spines, especially the males, but also become whitish, then begin growing darker. You can see the various stages I've documented so far on our Black Iguana page at http://www.backyardnature.net/yucatan/iguana-b.htm.

So, there you go. Don't depend too much on pictures in one field guide, and don't get stuck on wrong first impressions.

*****

SALTWORT
In mud at the very edge of standing, salty water in the mangroves often there's a much branching, woody-stemmed bush about two feet high (60cm) bearing short, slender, succulent leaves -- and nowadays pea-sized, yellowish fruits -- as seen at http://www.backyardnature.net/n/14/141026sa.jpg.

In certain mudflats where water stands at high tide or after rains, this bush forms dense, one-species colonies, and it's very common nearly everyplace where saltwater meets mud. But, what wildflower or bush displays such a combination of succulent leaves and fruits? The succulent leaves could belong to the North's rock-loving stonecrops, genus Sedum, as you can see at http://www.backyardnature.net/n/14/141026sc.jpg.

However, the fruits are unlike anything Northerners are likely to find in woods and fields, like little yellow-green potatoes with "eyes" irregularly scattered across their asymmetrical forms, as shown at http://www.backyardnature.net/n/14/141026sb.jpg.

The fruit's irregular lumpiness can be explained by its technically being considered a "drupaceous syncarps." The word drupaceous means "like a drupe," and a drupe is a fruit such as a peach, with a fleshy covering over a hard seed or pit that doesn't split open at maturity. Syncarps are "multiple fruits" derived from clusters of individual fruits that as they mature and enlarge merge with one another to form a single larger, fruit-like item, such as a pineapple, mulberry or Osage-orange. On our plant's multiple fruits, each thing looking like a potato's eye is the remnant of a calyx and sexual parts of a single flower. Each flower's enlarging fruits have fused so completely that there's little indication that it all started out as a cluster of flower ovaries.

The reason that this combination of having multiple-type fruits on a bush with succulent, stonecrop-like leaves doesn't register in the minds of temperate-zone plant fanciers is that this plant is a member of a plant family, the Bataceae, whose members only show up along the coasts of tropical and subtropical lands. The Bataceae family is so peculiar that it contains only one genus, the genus Batis, and in Batis there are only two species, of which our mangrove-mud-loving shrub is one. It's BATIS MARITIMA, which goes by several English names, including Saltwort, Beachwort, Turtleweed, and Pickleweed. It's distributed coastally from the Carolinas and southern California south to northern South America and throughout the Caribbean area, plus some Pacific islands, including Hawaii, where it's thought to have been introduced.

Saltwort is extraordinarily tolerant of very high salinity and can survive being covered by water for long periods. These adaptations enable it to be very important ecologically when it becomes a major colonizer after mangroves are destroyed by hurricanes. It grows slowly in soils with high salt concentrations but suffers little competition from other plants. It deals with very salty water by "sequestering," or setting salt aside, in its cells' vacuoles, and eventually shedding the leaves when their salt content reaches a certain level.

It's also been found that Saltwort roots are colonized by a certain kind of fungus technically referred to as a "vesicular-arbuscular mycorrhiza." This relationship indirectly reduces water stress on the plant, and improves phosphate nutrition. The term vesicular-arbuscular refers to a kind of mycorrhiza in which the fungal hyphae penetrate the cortical (bark) cells of the roots of a vascular plant.

Not only does Saltwort perform the important job of occupying and thus stabilizing muddy areas that are so salty and waterlogged that other plants can't live there, but also their succulent, salty leaves are nice to nibble on. Sometimes folks sprinkle them in salads, and in some places even cook them as greens in pots, or serve them up pureed or pickled.

In Puerto Rico, traditionally it's been used in folk herbal medicine to treat gout, eczema, psoriasis, rheumatism, blood disorders, and thyroid disorders.

This homely looking little bush living in salty mud is worth knowing and tipping one's hat to.

*****

BLACKBEADS FLOWERING
In sometimes-flooded ground in the mangroves, growing among Black Mangroves, a dense, much branched, waist-high bush with shiny, leathery leaves bore white, spherical flowering heads issuing a sweet fragrance that put me into the mind of late spring or early summer up north -- something between plume blossom perfume and a freshly cut hay field, just delicious. You can see a branch of it at http://www.backyardnature.net/n/14/141026pi.jpg.

The flowering heads were very like those of the many species of Acacia. A close-up of a head showing shaving-brush-like clusters of stamens tipped with tiny, pollen producing filaments, the stamen clusters overtopped by several single styles extending from the ovary nestled in the calyx to beyond the zone of anthers is shown at http://www.backyardnature.net/n/14/141026pk.jpg.

Having the styles longer than the filaments encourages visiting pollinators to brush against the styles' stigmas first thing as they approach the flowering cluster, depositing pollen on the stigmas, before continuing into the flower cluster to the zone of anthers where pollen awaits to be dusted onto the pollinator.

Also like acacias, the individual flowers produce numerous -- more than ten -- stamens, as you can confirm at http://www.backyardnature.net/n/14/141026pl.jpg.

However, acacia leaves generally are twice divided and bear many small, confetti-like leaflets. This bush's leaves are twice divided, but in a very peculiar and distinct manner, producing only four fair-sized leaflets, as shown at http://www.backyardnature.net/n/14/141026pj.jpg.

We've seen this interesting combination of acacia-like flowering heads on woody plants with twice-divided compound leaves bearing only four leaflets, on the important tree introduced at http://www.backyardnature.net/mexnat/pithecel.htm.

That page shows a member of the genus Pithecellobium, species of which are woody plants often known as blackbeads. They're called blackbeads because their beans are hard, shiny and black, serving as beads for anyone needing a pretty, organic necklace. So, here we have another species of blackbead.

This second, mangrove-swamp-loving species is PITHECELLOBIUM KEYENSE, mostly a Caribbean species found along the coast of southern Florida, the Yucatan Peninsula and most Caribbean islands. In US field guides it's often called the Florida Keys Blackbead, but that name won't do down here and in the Caribbean. Sometimes it's also called Rams Horn and Apes Earring because of its curled beans.

Fact is, there just isn't any good, commonly accepted English name. I'd be tempted to call it Mangrove Blackbead, but I read that elsewhere it grows on sand and limestone, in pine woodlands and even in disturbed areas. It seems to be a tough species. It's even sold in garden shops, which makes sense because of its pretty, lustrous, evergreen leaves, its wonderful flower fragrance, and its striking, coiled legumes.

*****

A LOOK AT RÍO LAGARTOS
At http://www.backyardnature.net/n/14/141019mp.jpg we've seen that Río Lagartos from high up looks like a white pyramid projecting into a lagoon behind a long barrier island separating Río Lagartos and the lagoon from the Gulf of Mexico. That view also shows that the town is fairly well defined with not much "sprawl." Houses and streets go to a certain point where water, mangrove swamps or low scrub forest is encountered and simply stops. The streets are somewhat narrow and fairly well maintained, though the town is so flat and so near sea level that after rain water tends to pool in the streets and drainage in ground-floor bathrooms can be sluggish. A typical street is shown at http://www.backyardnature.net/n/14/141026rj.jpg.

A striking feature of Río Lagartos -- at least to Northerners -- is that people here like bright colors, as you can confirm http://www.backyardnature.net/n/14/141026ri.jpg.

What's missing in these pictures is the noise, for it's mid morning when popping motorbikes are zipping up and down streets, people have their radios on loud, dogs are barking and whining all over town, Great-tailed Grackles are whistling, scraping and screeching in palm trees, and all kinds of folks are going up and down nearby streets hawking fruit, tamales, atole, 20-liter plastic bottles of purified water and other items from pushcarts, motorbikes equipped with carrying platforms, and the backs of pickup trucks, and they let us know their whereabouts with a cacophony of bell ringing, horn tooting, whistling in various formats, and calling through loudspeakers mounted on truck cabs.

The town's streets meets the water abruptly, as seen at http://www.backyardnature.net/n/14/141026rk.jpg.

In that picture you can see that from Río Lagartos all views across the water discover a slender, dark green band of vegetation on the horizon separating the water from the sky. That's mangrove swamp, where pink flamingos live, as well as a huge variety of other interesting organisms. Wherever the town meets the water there is no beach or exposed muddy area, but rather a solid storm wall to which fishing boats can be tied, as seen at http://www.backyardnature.net/n/14/141026rl.jpg.

Those bamboo poles at both ends of the boats are used for catching octopuses. At sea, three or maybe four lines dangle into the water from each pole and at the end of each line a crab is tied. The fisherman watches the strings, and when one goes taut, then probably an octopus has claimed a crab. Pull on the string, the octopus thinks the crab is getting way, and renews his efforts at hanging on. In such a way, without a hook, the fisherman pulls in his octopus.

Most of the time from along Río Lagartos's western side you can see across the estuary a diffuse, pink line between the mangroves and water. Those are flamingos. An interesting shot from out in the estuary toward town, through some flamingos, is shown at http://www.backyardnature.net/n/14/141026rs.jpg.

Río Lagartos is mainly a fishing village, and quite a few fishermen offer boat trips to see flamingos and other critters out in the mangroves. The town hosts many kitchen-sized grocery stores, rustic and not-so rustic restaurants and "posadas," posadas being lodgings for visitors. The citizens of Río Lagartos are very friendly to visitors, though they're different from people in similar-sized towns elsewhere in the Peninsula populated mainly by the Maya. Ever since boats could come and go from far away all kinds of people have been visiting this part of coastal Yucatan, and sometimes they stayed, mixed in and passed along their genes and living patterns. The fact that Río Lagartos is more a coastal fishing town than a Maya one shows in the people's looks and behavior.

Most people here are just getting along, and when you hear how little money they make you wonder how they survive. Life in Río Lagartos is marked by this inescapable fact: That as the population grows there are more and more fishermen, more and more boats going out each morning, but fewer and fewer fish. A biologist I know says that within maybe four or five years it'll simply be impossible to survive here fishing, and no one knows how that can be dealt with. A few years ago two attempts were made at aquaculture -- growing fish in cages or netted-in areas -- and those attempts were successful. However, in both instances the harvest was stolen, the owners got discouraged, and didn't try again.

The town, then, so colorful and friendly, is a microcosm of what's happening all over the Earth. People everywhere want to do the right things, yet while many realize that their way of living is unsustainable, hardly anyone is willing or able to change their behavior. And so, things keep careening toward... what?

Visitors to Río Lagartos not only get to enjoy the town's charm, color, and the surrounding area's riot of beautiful plants and animals doing fascinating things, but also they can feel good about spending vacation money here. Dollars spent here bounce all over town, and also make it more likely that the surrounding Rio Lagartos Biosphere Reserve will be protected, if not because it's the right thing to do then because it attracts money to where it's needed.

If you'd like to visit, let me know.

*****

FEATURED ESSAYS FROM THE PAST:

"Bea's Sugar Maples" from the November 5, 2007 Newsletter, at http://www.backyardnature.net/n/p/071105.htm

"Camping" from the May 18, 2003 Newsletter, at http://www.backyardnature.net/n/p/030518.htm

*****

Best wishes to all Newsletter readers,

Jim

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