JIM CONRAD'S
NATURALIST NEWSLETTER

Issued from Sierra Gorda Biosphere Reserve Headquarters in
Jalpan, Querétaro, MÉXICO

June 2, 2007

BLACK HAWK MAULS GIANT TOAD
Last weekend I camped beyond the far end of the reservoir, a bit up the main arroyo feeding the lake. Early Sunday morning when just enough light filtered into the narrow valley for birds to start flying up and down the intermittent stream I sat cross-legged in my tent's door gazing across a green pool of water. I'd pegged the tent beneath a big Mexican Sycamore where I had a good view up and down the stream, which was strewn with white, rounded, hippopotamus-size limestone boulders. You can see the exact view from my tent in a photo taken the previous sunny afternoon at http://www.backyardnature.net/n/07/070602sc.jpg.

I'd chosen the spot hoping to see wildlife visiting the pool to drink. During the night I'd heard lots of frogs and something knocking rocks about, but that was about it -- except for the sharp, excited-sounding whistles near my tent at dusk the previous day and first thing that morning. The whistles had reminded me of Woodchuck warning calls, so I'd figured it was some kind of mammal with a den in the rocky ledge behind my tent annoyed by my presence.

At the corner of my vision suddenly there was quick movement, a splash, and by the time I'd focused on the action I saw about 30 feet away a large, black hawk carrying something heavy in his talons. Apparently the thing being carried weighed too much to fly far with, for the hawk landed with it at the water's edge. The binoculars told the story: A Common Black Hawk had just plucked something looking like a Giant Toad from the stream.

What a view I had, the tent serving perfectly as a wildlife blind. The hawk was all black except for two conspicuous white bands on his tail, a brightly yellow, curved beak, and exceptionally long, yellow legs. You can see what a Common Black Hawk looks like and hear a version of its sharp whistles at http://identify.whatbird.com/obj/441/overview/Common_Black-Hawk.aspx.

The whistles at the above site sound perfectly hawky, but the ones I heard were just short, agitated-sounding outbursts.

That poor toad! The hawk perched atop it apparently puncturing and repuncturing its body with his talons. Several times a minute, with a brief fluttering of wings, the hawk would jump straight up, raising the toad six inches or so, and I interpreted this as the hawk trying to gain better purchase on his prey, thus probably making new holes in him. After every three to five jumps the hawk would bend forward and cut at the toad with his big, curved beak, sometimes seeming to carve out chunks which he'd swallow. This went on a good 15 minutes.

Up until this time I wasn't 100% sure that the prey was actually a Giant Toad, so now I emerged from the tent and began inching closer. The hawk would have none of this. He flew off, dropping the toad with a heavy plop onto the limestone bed. Reaching the toad and confirming my identification, I was amazed to find him still capable of righting himself and gamely trying to make it to water. When I drew close he took in air, bloating his body considerably. I've read that Giant Toads do this to make themselves too large for certain predators' mouths, but now I wondered whether another advantage might not be to separate the skin from vulnerable organs inside, by lots of air.

The hawk was perched nearby casually with one yellow leg drawn up into his black chest feathers, glaring at me, so I left the scene, hoping I'd not irretrievably disrupted an important moment in the local ecosystem's workings.

*****

GIANT TOADS SKRONKING
I'd known that Giant Toads occupied the pool next to my tent even before the hawk had snatched one out. The night before many Giant Toads had erupted with their powerfully percussive. At a distance Giant Toads sound like large, idling boat-motors but up close their calls are unbelievably explosive and loud, like the popping, skronking noise made by a hand slipping along a heavily rosined string attached to a large sounding-board.

The sound of Giant Toads comparatively gently calling from a distance can be heard by clicking on the white-triangle button in the blue box at http://concise.britannica.com/ebc/art-19025.

You can see a Giant Toad photographed back when I was at Komchén in the Yucatan at http://www.backyardnature.net/yucatan/toad-gnt.htm.

*****

DUSKY DANCERS ON A LEAF
At the placid pool next to which I camped there were damselflies at the water's edge doing something I've never seen before, as shown at http://www.backyardnature.net/n/07/070602dm.jpg.

That picture shows several pairs of hooked-together damselflies resting on a mostly submerged Mexican Sycamore leaf. I've seen plenty of damselflies hooked together, but never a group like this clustered so closely together. Nowhere else along the pool's banks was there another such gathering, though several partially submerged sycamore leaves appeared to offer identical resting opportunities.

Dr. John at the University of Texas identifies the damselflies as ARGIA TRANSLATA, sometimes going by the name of Dusky Dancer. That species has an enormous distribution from Ontario to Argentina.

When male and female damselflies hook together as shown in the photo, the male grasps the female behind her head, at her prothorax, using "anal appendages." Therefore, in the picture, the upright individuals are males while the ones below, with the tips of their abdomens in the water, are females. When male and female damselflies join like this they're said to be in their "tandem position."

After hooking together the female bends up her rear end, or abdomen, so that her reproductive opening touches the male where sperm are stored. During the sperm-transfer process they form a heart-shaped union and are said to be in their "wheel position." Sometimes you can see damselflies in their wheel position, and that's something special to look for.

There's a much more detailed, well illustrated description of damselfly reproduction at http://www.geocities.com/brisbane_dragons/Mating.htm.

*****

BUTTERFLY CLOUD AT THE WATER'S EDGE
Probably this last week's prettiest moment occurred at a muddy edge of the reservoir. Though the reservoir's shoreline extends for miles there was something about the mud at this particular spot that the butterflies really liked, for nowhere else did I see them gathering in such large numbers. Surely more than a hundred of several species were all crowded together there, nearly all fluttering their upward-held wings. I'm guessing that the wing fluttering helped them keep their balance, for a breeze blew off the water and sometimes vagrant gusts almost tipped the butterflies into the sticky mud.

Very, very slowly I scooted on my butt to get close enough to the gathering to take close-ups. (One can speak of a "rabble" or a "swarm" of butterflies, but neither of those seems appropriate; I thought of it as a "megafluttering.") However, despite my care, once I was close enough to make pictures most of them scattered and didn't return.

Still, a few remained, and I did get a couple of pictures. You can see Giant Swallowtails, PAPILIO CRESPHONTES, their heads pointed into the wind, at http://www.backyardnature.net/n/07/070602b6.jpg.

Another group, reminiscent of North America's Zebra Swallowtails, but which I'm calling Dark Kite-swallowtails, EURYTIDES PHILOLAUS, appears at http://www.backyardnature.net/n/07/070602b5.jpg.

*****

MOUSE WARS
Those of you who have been with me since my Mississippi days may recall my adventures trying to nonviolently remove mice from my tiny, book-packed trailer out in the woods. The mice were big-eyed, high-jumping White-footed Mice, native to most of eastern and central North America.

A couple of weeks ago a mouse moved into my casita here in Jalpan, and it's taken me a while to catch it. I did catch it once using the tip-bottle method that had been so successful in Mississippi, but the critter escaped and learned from the experience not to enter food-containing plastic bottles teetering at the edge of my desk. I could hardly wait to catch the mouse, anticipating that it might be a native Mexican species beautifully adapted to the scrub beyond the fence just outside the casita.

Finally at dusk the other day I saw the mouse climbing up behind a window drape and I grabbed her through the drape's fabric. I say "her" because the moment I had her in my hand I felt the plumpness of her body, and I didn't think it was all from eating my peanuts and oatmeal. I nudged her into a plastic bag and couldn't wait to start identifying. You can see her in my bag at http://www.backyardnature.net/n/07/070602mo.jpg.

Well, best I can figure out, she's a plain old House Mouse, MUS MUSCULUS. Still, even a House Mouse has "field marks," so it was interesting to review what makes a House Mouse a House Mouse.

As the table midway down the page of my Rats, Mice & Voles page at http://www.backyardnature.net/rats.htm shows, currently about 125 species of mousy, ratty rodents are found in North America north of Mexico. There are 17 species of deer mouse (My White-footed Mouse was a deer mouse), as well as 20 species of pocket mouse, 12 species of wood rat, 16 of kangaroo rats, 26 of voles, etc.

The vast majority of our native mice and mouse-like creatures have white fur on their bottoms, like my earlier White-footed Mice. Therefore, an important feature of the House Mouse, which is a native from the Mediterranean area through Asia, is that its bottom fur may be a tiny bit paler than its top fur, but it's not really white. Moreover, the tops of its feet are gray, not white. Tails of most native mousy species are bicolored -- dark on top but white below. Also, the House Mouse has relatively smaller eyes than most of our native mice.

I released my Mus musculus down next to the reservoir in a vine-overgrown stone fence near where visitors throw their garbage. I assume that the area already is occupied by the species and this one, being away from her scent trails and in unknown territory, will fall easy prey to one of our abundant pygmy owls or roving house cats.

There's a lot of information about the House Mouse here.  

*****

OWL FLY BENEATH THE LIGHT
Early one recent morning, beneath a high-efficiency security lamp mounted on one of my casita's outside walls, clinging to the white stucco I found the strange, dragonfly-size, dragonfly-like insect shown at http://www.backyardnature.net/n/07/070602of.jpg.

But of course no dragonfly bears such long antennae as the creature in that picture. The antennae alone prove that it's not a dragonfly. In fact, it doesn't even belong to the same ORDER as dragonflies, which means that it's approximately as unrelated to dragonflies as a sparrow is to a woodpecker -- different orders.

I wouldn't have known what my wall-percher was if I hadn't found a larva of this kind of insect when I lived near Sandy Creek in Mississippi, writing about it under the heading "Little Dragon with Big Pincers" in my September 5th, 2004 Newsletter. You can see a scanning of that small but mean-looking larva at http://www.backyardnature.net/pix/owlflylv.jpg.

My wall-percher was an owlfly, closely related to the antlions whose sharp-pincered larvae, often called doodlebugs, dig conical pits in sand and dust, position themselves beneath the sand at the pit's bottom, and await prey who tumble into the pit. That's different from owlfly larvae, though, who with their large jaws roam around hunting prey on the ground and in low vegetation.

Adult owlflies feed on other flying insects. I read that when they're disturbed they release a strong, musk-like chemical that deters enemies, but I didn't harass my wall-percher so I didn't notice that. It's assumed that by poking their abdomens into the air when they're perching their enemies may confuse them with broken twigs.

That strategy sure doesn't work, however, when they're resting on a white stucco wall.

*****

SYCAMORE STIPULES
Beginning botany students often find it hard to understand about "stipules." A typical definition of a stipule is that it's "a small leafy outgrowth at the base of a leaf or its petiole (leaf-stalk); usually stipules occur in pairs and are soon shed." A botanist might need the further qualification that a stipule is to be understood as a basal appendage of a leaf's petiole, the three parts of a complete leaf being the blade, petiole and the stipules.

The Mexican Sycamore shading my tent last weekend had very prominent stipules, as do all sycamores. You can see them surrounding the tree's leaf-petiole bases at http://www.backyardnature.net/n/07/070602st.jpg.

In that picture, notice how stipules below the newest leaves are fresh and green but those subtending the oldest leaves already are turning brown. Eventually they'll fall off leaving a "stipular ring," or scar, encircling the stem. Stipule scars can be very helpful identifying twigs during the winter. Often the scars appear on twigs as tiny slits at the tops of leafscars. Usually you don't see them unless you're looking for them.

Probably stipules occur in less than a quarter of all flowering-plant families, so, when you're trying to determine what family an unknown plant belongs to, checking to see if it has stipules or stiplule scars is a good idea.

In those plant families with stipules, the stipules behave in various ways. Non-green stipules quickly falling off before a leaf finishes expanding may have no real purpose, and can be regarded as evolutionary vestiges. Other times, as with our sycamore, stipules are large and green, helping photosynthesize food during the critical leaf-expanding process. Sometimes stipules harden and become spines at the bases of petioles, as with Blacklocusts. Among the greenbriars, stipules have evolved into tendrils. Desert-living Creosote Bushes bear corky stipules but it's not clear what they do. Some stipules develop glands providing nectar for ants, who defend the plant from herbivores.

Especially if you have a handlens, you might enjoy looking for stipules or their scars. They form a whole arena of interest all by themselves.

*****

NOT MAPLE FRUITS
Most plants and animals you see here have close relatives in North America, and that's helpful when trying to identify them. For example, maybe you'll recognize a tree as definitely belonging to the oak genus, Quercus, or the pine genus, Pinus, even though you've never seen that particular species before. However, sometimes you run into species whose relationships you just can't imagine.

For example, right now something showing up on the ground along trails and roadsides are the fruits shown at http://www.backyardnature.net/n/07/070602sg.jpg.

The fruits are shed by the vine you can see at http://www.backyardnature.net/n/07/070602sh.jpg.

The fruits look a lot like maple fruits, or samaras, except for their finlike crests. Also, we just don't have maples in this part of the world.

It took a while to figure out that the vine is probably STIGMAPHYLLON RETUSUM, which makes it a member of the Malpighia Family. That family just doesn't make it farther north than subtropical parts of the US -- even though in the tropics and subtropics it's a fairly common family, comprising about 60 genera and 700 species.

What do you do when you run across a plant you can't even place into its family?

One fun thing is to use the dandy "World Wide Flowering Plant Family Identification" page at http://www.colby.edu/info.tech/BI211/PlantFamilyID.html.

There you just check boxes corresponding to characters applying to your discovery, click on "Submit Form," and you're presented with a list of plant families your unknown plant possibly could belong to. The more characters you list, the shorter your list grows, and you keep adding characters until your list consists of only one possible family.

This page provides a great way to learn the anatomy of flowering plants, by looking up the terms appearing in questions you don't understand.

The Malpighia Family. How about that? Nice.

*****

PLANT CALLED SCORPION TAIL
One plant flowering here these days in rich, moist soil in full sunlight along the reservoir's shore is a tropical and subtropical species reminiscent of a well-known Northern garden plant. See if you can guess its affiliations by looking at the picture at http://www.backyardnature.net/n/07/070602he.jpg.

The most characteristic feature of that plant is how its inflorescence, or flower cluster, coils tightly at its loose end. Also notice how its lower flowers are more advanced in their development than those in the tightly coiled outer part, and that all flowers appear on just one side of the inflorescence axis. Such coiling inflorescences are said to be "scorpioid," referring to the scorpion's upward-curled tail.

The scorpioid inflorescence in my picture probably reminds many of you of the garden's usually-blue-flowered Common Heliotrope. The plant in my picture is indeed a heliotrope, HELIOTROPIUM ANGIOSPERMUM, often called Scorpion Tail. It's distributed from the US Deep South through the Americas to Brazil. Sometimes it's also called the Butterfly Heliotrope, and with good reason: You just should have seen them flitting about.

By the way, scorpioid inflorescences are restricted to a handful of plant families, so when you see flowers arranged like that it should help you figure out which family it belongs to. Usually heliotropes are placed in the Borage Family (Bluebells and Forget-me-nots), but some are now placing it in its own Heliotrope Family. Another family often with scorpioid inflorescences is the Waterleaf Family (Phacelias).

*****

TADPOLE THOUGHTS
Once again this week hoards of tadpoles impressed me with there sheer numbers, as shown in the picture at http://www.backyardnature.net/n/07/070602tp.jpg.

Those tadpoles were in the green pool before my tent door, and on the afternoon of my arrival at that site I watched them for hours migrating back and forth across the pool, an unhurried black stain diffusing through the greenness like a dusky fragrance filtering through a forest.

That same day I'd been inside a butterfly megaflutter, I'd walked miles through Frogfruit-mantled mudflats overly supplied with tiny toads, I'd walked for hours along the lake's shore filling my head with birdsong, the sound of wind flapping in my ears and waves lapping at the shore's edge, walking, walking, walking, the backpack creaking, binoculars thumping against my chest and sweat from beneath the backpack running down the crack in my butt, white clouds, blue sky, the fishy, muddy odor of fresh wind off a lake...

I met several families picnicking alongshore, the men usually fishing with throw-lines, the women usually sitting in the grass with kids all around. Most people just smiled, said "Buenos tardes" and I walked by but one man wanted to talk. He asked me what state I was from. I was born in Kentucky, I said. "Tobacco," he said. "Tabaco y caballos," I replied -- tobacco and horses, and by saying this I showed I knew how to talk in the world the man occupied. Tobacco and horses are work Mexicans do in Kentucky. If I'd said "Florida," the man would have said "Oranges." Usually it's like that, the US a mosaic of kinds of jobs to be had, for most people everything else up there not really mattering, no, not that much.

The man's fingers were thick, his hands calloused, his muscles hard, and his wife while not pretty and with a little fat pooching over her belt exuded womanly essence, wholesome but voluptuous femininity, a pretty thing for a man to look at there in the grass, so good to the kids.

That day, the tadpoles, butterflies, birdsong, wind, sunlight, tobacco and horses, muscular men and voluptuous women all mingled in my mind, somehow all being the same thing, one kaleidoscopic, polytonal pungent thing, something vigorous, sensuous, ravishing, gladsome.

Then I put my tent beneath the big sycamore, and waited.

*****

Best wishes to all Newsletter subscribers,

Jim

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