September 25,  2011

KISKADEE MYSTERY
First, a little background: In the Yucatán we have three flycatcher species with black-and-white-striped heads, yellow underparts and brownish-gray upperparts.

There's the Boat-billed Flycatcher, the least common of the three, possessing a very broad bill and showing no reddishness in its brownish-gray upperparts. It calls with a grating, complaining EEIHRRR, EEIHRRR... Our page nicely illustrating one is found at https://www.backyardnature.net/yucatan/bb-fly.htm.

Similar in shape and color but much smaller, and with a much smaller beak proportionally, usually occurring in small flocks instead of singly or in pairs like the others, and issuing a variety of shrill, nervous-sounding calls, is the Social Flycatcher, shown at https://www.backyardnature.net/yucatan/social-f.htm.

In small towns and villages and on ranches the most typical of the three look-alike species is the American-Robin-size Great Kiskadee, PITANGUS SULPHURATUS. You know you have a Kiskadee mostly because it loudly and shrilly calls kis-k'-DEEEE, kis- k'-DEEEE. Also, in good light its wings and tail display a bit of rustiness. Of the three species, here I've only seen Great Kiskadees, though up at Hacienda Chichen they were the rarest of the three species. Now take a look at a couple of our beach Great Kiskadees at https://www.backyardnature.net/n/11/110925kk.jpg.

What on Earth are they doing? Certain bird species pass food back and forth but I've not heard of Kiskadees or their relatives (they're flycatchers) doing it. Also, if they're exchanging seeds, how does it work with both birds holding seeds? With my poor vision I couldn't see what happened after the picture was snapped. I'm guessing that they are Gumbo-Limbo seeds.

Notice that the bird on the left seems to be in the process of dropping the seed, since its beak is open beyond the width of the seed. Maybe both birds are regurgitating seeds? Both seeds appear devoid of flesh.

If anyone has insight into what the birds are doing, let me know so I can tag this photo for search engines. I think we've blundered onto a very interesting picture.

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AN UPSET ROADSIDE HAWK
One morning a Kiskadee was busy harassing a Roadside Hawk who has been hanging around for months. You can see the hawk expressing himself to his tormentor at https://www.backyardnature.net/n/11/110925rh.jpg.

Roadside Hawks -- that's their commonly accepted English name -- are buteos, in the same genus as the North's Red-tailed and Broad-winged Hawks.

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SANDERLING PUZZLE
I'm used to seeing Sanderlings in small to large flocks mechanically chasing waves back and forth on the beach and I regard them as smallish birds, so I didn't think of them when I came upon the two larger, lollygagging birds appearing in the picture at https://www.backyardnature.net/n/11/110925sd.jpg.

In my old field guide, really no illustrations matched the two birds. Once again I had to write my master-birder friend David in Bermuda. David replied that " ...the bigger, whiter two shorebirds are Sanderlings. The smaller, probably an adult Western." Western Sandpiper, that is.

In my old Robbins field guide the backs of winter Sanderlings are somewhat vaguely mottled pale brown, not starkly black-and-white as on these birds.

Really this business of identifying shorebirds in their non-breeding plumages is tricky. You just need years of experience to get a feeling for it. Or a friend like David.

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WHITE-TAILED KITE
A month ago we got a frontal view of a White-tailed Kite. This week we were granted a back view, as shown at https://www.backyardnature.net/n/11/110925kt.jpg.

It's interesting that this bird's tail isn't really white. Howell describes the juvenile's tail as "pale grey with dusky subterminal bar." I'm not sure about that subterminal bar, but the tail certainly is gray.

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TARANTULA HAWK WASP
On the white sand road late the other afternoon when everything already was in shadow, I came upon a very large wasp pulling a tarantula across the road, shown at https://www.backyardnature.net/n/11/110925t2.jpg.

We've all seen wasps carrying spiders to their nests but this was my first tarantula. Suddenly the wasp left the tarantula in the middle of the road, and while it wandered around checking things where I got the nice close-up of the tarantula's "face" at https://www.backyardnature.net/n/11/110925t3.jpg.

As soon as I withdrew from the tarantula, the wasp returned and continued pulling her prey across the road.

A tarantula expert I correspond with tells me that probably the tarantula in our picture is an immature BRACHYPELMA VAGANS, or at least something currently called B. vagans because the experts don't know what else to call it. If that's so, thus one is different from the poorly known and relatively small tarantula species we've seen up at Chichén Itzá, the Yucatan Redrump, Brachypelma epicureanum.

It took volunteer identifier Bea in Ontario to direct me to a group of wasps known as tarantula hawks, who do drag tarantulas around. The group incorporates two genera, Pepsis and Hemipepsis. Because of our wasp's large size I'm guessing it's a Pepsis.

In the 2006 book The Maya tropical forest: people, parks, & ancient cities by James D. Nations I read that female tarantula hawk wasps find their tarantulas by flying about using their sense of smell, looking for female tarantulas in their burrows or males in the open. If a female is found she's drug from her burrow, stung and paralyzed, and then returned into her burrow where a single egg is laid on (not inside of) her abdomen. Then her burrow is sealed. If a male tarantula is encountered he's stung, the wasp digs a narrow burrow, drags the paralyzed male into it, and lays an egg on him.

When the egg hatches, the wasp grub sucks the comatose tarantula's body fluids. Once the grub is large enough it tears open the tarantula's body, and eats remaining goodies. The tarantula remains alive during most of its being eaten because the grub eats vital organs last of all. In the end, only the tarantula's "husk," or exoskeleton, is left. Then the larva pupates and digs its way out of the burrow, flies away, and begins the whole process over.

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"WILD" CANISTEL
Beside the white sand road a 15-ft-tall tree (4.5m) bearing leathery, evergreen leaves like the North's Persimmon tree caught my attention. It bore yellow- orange, persimmon-like fruits. "Another persimmon," I thought when I saw it, because in July we'd found real persimmons maturing here -- though of a species different from North America's. You might like reviewing that July tree at https://www.backyardnature.net/yucatan/persimmn.htm.

Now look at this week's similar species at https://www.backyardnature.net/n/11/110925xy.jpg.

The first hint that this week's tree is NOT a persimmon is that the fruit is asymmetrical, with a blunt little nose off to one side. Persimmons are spherical. Also, at a persimmon's base typically you find the remains of a large, woody calyx. Our present fruit's calyx isn't particularly large. The main hint that we don't have a second persimmon species, though, is that when I bit into the fruit the flesh was sweet, and a little waxy, similar to our July persimmon, but inside instead of several seeds of the kind you expect in a persimmon, there was just one. You can see the large, two-toned seed I gnawed clean at https://www.backyardnature.net/n/11/110925xz.jpg.

The dark, lower part of that seed is the seed coat, which on most seeds covers nearly the entire seed. The paler, top part is the hilum. In most seeds the hilum is no more than a small scar formed where the seed's umbilical-cord-like "funiculus" once connected the seed to the ovary containing it, or fruit wall. On the seed in our picture the hilum is enormously enlarged, the same way it is on Buckeye and Horse Chestnut seeds. And on the big seeds of the tropical fruit called Mameys...

Down here we have no relatives of Buckeyes or Horse Chestnuts but several species are related to the delicious Mamey. This helped me figure out that what we have here is Canistel, POUTERIA CAMPECHIANA, belonging to the same family as the Mamey -- and the Chicozapote for that matter -- the Sapodilla Family, or Sapotaceae.

We've seen Canistel before, but it's cultivated form, which produces a much larger fruit, but with the same good taste. You might want to check out that fruit at https://www.backyardnature.net/yucatan/canistel.htm.

Sometimes Canistel is called "the Maya Fruit" because the Maya like it so much. In fact some experts say that Canistel is one of the most underrated of tropical fruits, and should be planted much more than it is.

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RED MANGROVE FLOWERING
Red Mangrove, RHIZOPHORA MANGLE, is the easiest-to-identify of the Yucatán's four mangrove species because of its flaring aerial prop roots, or "stilt roots," which you can see on our Red Mangrove page at https://www.backyardnature.net/yucatan/mang-red.htm.

On that page also notice how the fruits germinate while still hanging on the tree, issuing oversized, spearlike roots up to about a foot long. Sometimes the fruits fall so that the roots stab into the mud, automatically planting the young tree.

The long-rooted fruits hanging on the tree are so attention-getting that the flowers preceding them often are overlooked. You can see how the pale yellow, leathery, star-shaped flowers arrange themselves in few-flowered, long-stemmed clusters from leaf axils at https://www.backyardnature.net/n/11/110925mv.jpg.

A picture of a little-less-than-inch-wide (2cm) flower with four pale yellow, leathery sepals and four whitish petals with cottony hairs on their inner surface, and eight stamens, can be seen at https://www.backyardnature.net/n/11/110925mg.jpg.

I'm guessing that the petals' hairiness provides footholds for visiting pollinators. The ovary is "inferior," meaning that the other main floral parts arise at the ovary's top instead of at its base. The resulting fruit is a little over an inch long (3cm), dark brown, and contains one seed which, as we saw, germinates while still on the tree. Plants producing such seeds are said to be "viviparous."

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SEA-GRAPES TASTE GOOD
Already back in June we looked at a Sea-grape bush heavily laden with fruits, still shown online at https://www.backyardnature.net/n/11/110612cc.jpg.

At that time I wrote that the fruits "are still a little immature" and suggested that the Chachalacas might eat them before I could get a chance to taste one. To my surprise, all during summer the Chachalacas ate very few and the fruits themselves only recently began reaching maturity. You can see a handful of ripe ones, one partially eaten, even at this date more green than the yellow or brown I've been looking for, at https://www.backyardnature.net/n/11/110925sg.jpg.

That picture also shows the single, hard seed found inside each fruit. The fruits have fuzzy skins, like peaches. The ripe fruits even smell and taste a tiny bit like peaches, but really they have their own taste, which is pleasant enough and nicely sweet. They also taste salty, but I can't say whether the saltiness is in the flesh itself or the salt-spray-exposed, fuzzy skin.

I'm surprised that the Chachalacas haven't harvested them all. In fact, the vast majority of ripe fruits appear to have fallen to the ground where they emit a powerful but not-unpleasant odor of past-ripe fruits that can be smelled a fair distance away.

I read that sea-grapes contain a lot of pectin, and as such are ideal for making jams and jellies. I'll bet they would also brew a tasty homemade wine.

In fact, Marcia has posted a recipe for "Sea Grape Vinaigrette" and "Sea Grape Jelly" down the page at http://www.mayanbeachgarden.com/trees.htm.

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A BIG, PRETTY CLUMPGRASS
Earlier this year I dreaded take nature walkers past a particular neighbor's entrance road because he'd planted several eye-catching ornamental clumpgrasses there. People always asked me what those grasses were, and I didn't know, because I'd never seen them flowering. The grasses were eye catching because they were big -- about eight feet tall (2.5m) and some twelve feet across (3.5m). You can see them at https://www.backyardnature.net/n/11/110925pi.jpg.

Now the grasses are flowering and I can hereby announce the handsome plant's name: SPARTINA BAKERI. Among its English names are Sand Cordgrass, Dune Cordgrass, Switchgrass, Marsh Grass, and Baker's Cord Grass. A close-up of one of the long, slender, lax, spikelike clusters of racemes is at https://www.backyardnature.net/n/11/110925pj.jpg.

The slender inflorescences with their closely crammed flowers differentiate Spartina bakeri from other large, ornamental clumpgrasses with more open, feathery flower clusters, such as Pampas Grass, Plume Grass, Maiden Grass and others.

Spartina bakeri is native to the US Southeast where it often grows in marshes and next to lakes. The ones here are on dry sand, but groundwater is just a few feet below. The grass is highly salt tolerant. In other words, here's a handsome species with a lot of potential for landscaping down here, and since new landowners here typically scalp their properties of native vegetation as soon as they arrive, all the help the land can get to stabilize its sand is welcome.

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FLOATING ROCKS
The other day a rock came floating ashore. If you can't imagine what that looked like, take a peep at https://www.backyardnature.net/n/11/110925pu.jpg.

Of course it was pumice, and there's a fair bit of it strewn along the sandy beach these days.

Pumice is volcanic rock. When highly pressurized lava is violently erupted from a volcano, it simultaneously cools and depressurizes. As it depressurizes, many tiny gas bubbles form in it the way gas bubbles do in soda-pops when the tops are removed, lowering the pressure inside the bottles. If the lava cools very fast, as by falling into water, the lava hardens into bubble-filled rock. And the resulting pumice rock is so lightweight that it floats! The rock is also soft enough to cut with a pocketknife, or scrape with a fingernail. Pumice with a notch cut into it is shown at https://www.backyardnature.net/n/11/110925pv.jpg.

I haven't seen pumice float in like this during the five months I've been here, though I'm told it happens from time to time. Along with pumice there's an unusual number of large tree trunks suddenly cast onto the beach. Often the trunks are charred or bear machete cuts. I'm guessing that someplace downcurrent a hillside has given way during the current rainy season. Probably the hillside had been devastated and destabilized by slash-and-burn agriculture -- killing trees by girdling them, then setting fire to "clean things up." When plant roots no longer hold the soil in place and leaf littler no longer caps it, sometimes whole mountainsides slop away. And if it's in a volcanic area, there's a good chance there'll be a layer of ash and pumice below the topsoil. The tree trunks and pumice float.

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VOLCANOES DOWNCURRENT
The Yucatan has no volcanoes, but there are plenty downcurrent. Awhile back when we looked at the origins of trash along the beach here we saw that most of it came from northern South America. Between Venezuela and the Virgin Islands, some 17 volcanoes are distributed among the Lesser Antilles. The island nation of Dominica has at least nine, and Grenada to the south has two, one of which, a submarine one, is named Kick-'em-Jenny. A website dedicated entirely to Caribbean volcanoes nicely maps them out and discusses them at http://www.caribbeanvolcanoes.com/.

La Soufrière Volcano on St. Vincent between Dominica and Grenada last erupted in 1979. In 1902 Mount Pelée on Martinique erupted killing about 30,000 people.

These volcanoes distributed among the islands of the Lesser Antilles occur in a north/south-running line, and that can be explained in terms of plate tectonics -- continental drift. The line of islands occurs along the eastern rim of the Caribbean Plate where it slides over part of the South American Plate. As this part of the South American Plate is forced downward along a "subduction zone," the descending rock heats from friction and high pressure, melts, and sometimes the resulting magma erupts upward, forming volcanoes.

And if the volcanoes occur at sea, sometimes they form islands like Dominica and Grenada.

And sometimes the erupting magma falls into water and cools so fast that it forms pumice rock, which floats.

Wikipedia's page explaining this in more detail is at http://en.wikipedia.org/wiki/Caribbean_Plate.

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TAPDANCING WITH SANDPIPERS
On online radio I hear a percussion showdown between a tapdancer and a drummer, and I decide that that's the way I want to do things, tapdance out the window onto the palmtree tops tap-tap, atop the seagrape tops tap-tap, onto the beach, the sandy beach with waves BOOM- swishhhhhhhh, BOOM-swishhhhhhhh, BOOM-swishhhhhhhh, tap-tap-tap down the sand sandpiper-peep-sixteenth-notes twittering peep-peep-peep twittering BOOM-swishhhhhhhh, BOOM-swishhhhhhhh, BOOM-swishhhhhhhh and me there spotlighted amidst it all Bojangling, big wide eyes big wide smile arched eyebrows sweating bullets tapdancing the morning away.

For, something there is beyond lugging this flesh around, beyond getting anchored in history and future, plodding, keeping low and being oneself as others define you, and when you tapdance, you can tapdance anyplace, like I'm telling you I did right here.

But, here's the thing: You're out there and everything is tapdancing, all those rattly-tattly sandpipers and BOOM-swishhhhhhhh, BOOM-swishhhhhhhh, BOOM-swishhhhhhhh waves, and when you get your own thing going, how do you keep up with who's doing what?

But, here's the next thing: You do it, you coordinate and you feed off those other dancers, and then you see: It's all one thing. It's all one big dance and there's a beat down below wavesplash/wingbeat/foot-tap, something like ommmmmmmmmmmmmmmmmmmmm.

So, there I was, tapdancing with sandpipers and the ommmmmmmmmmmmmmmmmmmmm began, and things came together, and things froze the way they were, and though I couldn't move my head or feet or anything I looked around, realized we'd forgotten to invite an audience, that we were doing all this just for ourselves, and I got tickled, and the sandpipers and the beach got tickled, and we all started laughing, and after we'd finished laughing we all just went back doing whatever we'd been doing before, just that now we'd done our tapdancing, had a good laugh, and now we'll see what comes next.

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Best wishes to all Newsletter readers,

Jim