JIM CONRAD'S
NATURALIST NEWSLETTER
Written at Mayan Beach Garden Inn 20 km north of Mahahual
on the Yucatán Peninsula's eastern coast just north of the
Belize border, in the state of
Quintana Roo, MÉXICO

December 29,  2008

A FEISTY ROYAL TERN
At http://www.backyardnature.net/n/08/081229tn.jpg you see a bird species occasionally showing up along the beach here. The birds are terns, not gulls. The family Laridae comprises the Gull Subfamily, the Tern Subfamily and the Skimmer Subfamily. Terns differ from gulls in that gulls possess relatively small, stout, hooked bills and, usually, rounded tails, while the bills of terns average somewhat larger, are pointed instead of hooked, and tern tails are forked.

The birds in the picture are Royal Terns, STERNA MAXIMA, and a confrontation seems to be taking place. When I showed the picture to Marcia, the hotel owner, she told me that a while back an ornithologist staying at the hotel told her that immature Royal Terns are famous for "acting out" in front of their parents. Sometimes the parents reciprocate with a bit of defensiveness but other times they just stand calmly and let the tantrum pass. I can't say for sure what's happening in the picture -- even whether the angry-looking one is an immature or not -- but learning this about immature Royal Terns makes tern watching more interesting now.

Royal Terns are one of three Mexican-tern species with black crests, and in the picture you can see how the crests can be raised. Usually the crest points backward giving the bird's head a flat-topped, swooped-back look but the bird in the picture with his crest erect looks almost horned.

As the picture shows, Royal Terns in winter plumage have white foreheads. Only for a short time during the species' breeding season does a solid black cap develop. Royal Terns are very similar to Elegant Terns, but Elegant Terns don't occur on Mexico's Gulf/Caribbean side, only on the Pacific. Royals can most easily be confused with Caspian Terns, but that species is larger, has a blood-red bill instead of the Royal's orangish one, and its tail is less deeply notched.

Royal Terns are strong flyers and strictly limited to saltwater, unlike some tern species who range inland. Royals occur from northwestern Mexico and the eastern US south to Peru and Argentina, and locally in western Africa.

Most tern species feed by plunge-diving for fish near the surface.

*****

AN UNSPOTTED TEETER-TAIL
"Teeter-Tail" is a name some people call the Spotted Sandpiper, ACTITIS MACULARIA, because as it walks it endlessly bobs its rear end up and down in a spectacularly exaggerated manner. And despite Spotted Sandpipers being conspicuously spotted during the summer, the one I encountered on the beach the other day didn't have a spot on it, as shown at http://www.backyardnature.net/n/08/081229ss.jpg.

Because the tail-bobbing makes this species so easy to recognize, and because it's such a common species in almost all environments with water nearby, including lazy streambanks and cattle ponds in the US, this is one of the best-known of American shorebirds.

I see Spotted Sandpipers much more inland than on sandy beaches. The one in the picture, in fact, behaved differently from other shorebirds I saw at the water's edge that day. Instead of running farther up the beach or flying away, this bird ran into a pile of driftwood and hid in the shadows as I approached quite near.

*****

UBIQUITOUS YELLOW-THROATED WARBLERS
I've already mentioned how common Yellow-throated Warblers, DENDROICA DOMINICA, are as they overwinter in much of Mexico, including the Chiapas uplands and the Yucatán. They're common along our narrow sand road running the length of the low ridge between the ocean and the mangrove swamps. This week I got the picture of a friendly one right in front of the hotel, shown at http://www.backyardnature.net/n/08/081229yw.jpg.

Many warblers lose their bright colors when they come here to overwinter but Yellow-throateds don't seem to change much.

Yellow-throated Warblers nest in the US Southeast and a little beyond, and overwinter in most of eastern and southern Mexico, the Caribbean and much of Central America.

*****

THE YEARLY CHRISTMAS BIRD-WALK
Longtime readers know that each Christmas I take an unhurried saunter around wherever I happen to be and jot down which birds I happen to stumble across. This Christmas morning about half an hour after sunrise it was 80°F (27° C), a stiff breeze was blowing off the Gulf, and it was balmy and partly cloudy.

Here basically there are two places to walk: Along the narrow sand road following the sand ridge separating the sea and the mangroves, and along the beach. A perfect two-hour walk I've taken many times is up the beach on the road, concentrating on the mangroves, then back along the beach. Here's what I saw this Christmas morning on that walk, with species listed in the order I saw them, so you can get a feeling for how the walk developed:

*** ALONG ROAD ***

  • CATTLE EGRET stabbing for crabs on the sandy road
  • MANGROVE CUCKOO watching me from roadside scrub
  • WHITE-EYED VIREO calling from mangrove edge
  • GOLDEN-FRONTED WOODPECKER pecking in dead mangrove
  • TROPICAL MOCKINGBIRD perched on tall dead mangrove
  • LEAST FLYCATCHER flycatching at mangrove edge
  • PALM WARBLER on sandy road tail-bobbing
  • GREAT-TAILED GRACKLE screeching beside beach house
  • HOODED ORIOLE singing in snag beside beach house
  • MANGROVE WARBLER, soft tch! call in Poisonwoods
  • YELLOW-THROATED WARBLER on snag among Poisonwoods
  • MAGNIFICENT FRIGATEBIRD, 2 sailing over road
  • YUCATAN JAY, 3 raucously complaining along road
  • CINNAMON HUMMINGBIRD zipping at mangrove edge
  • GREAT CRESTED FLYCATCHER calling wheep! wheep!
  • *** BEACH ***

    1. BROWN PELICAN diving just offshore
    2. TURKEY VULTURE sailing over mangroves
    3. SPOTTED SANDPIPER tail-wagging in driftwood pile
    4. SANDERLING, ±30 chasing waves in and out
    5. RUDDY TURNSTONE, ±20 among Sanderlings
    6. BLACK-BELLIED PLOVER with Sanderlings & Turnstones
    7. ROYAL TERN unmoving on Shoal Grass flat

    This list is about what I see every day. Occasionally a Laughing Gull flies by. A few days ago a Peregrine Falcon flew about 15 feet above me, and a couple of weeks ago a Common Black Hawk sailed down the beach screaming, but those were unusual events.

    *****

    STINGRAYS
    For a couple of days it'd been unusually hot, humid and fairly calm, so that biting gnats called Chaquistas were making working outside a bit hard. But then a norte began blowing in, bringing intermittent showers, temperatures down in the upper 70s and a broody feeling out over the ocean. Maybe that's why on my walk that day I saw things not normally seen. A big flock of parakeets spun overhead; a Peregrine Falcon flew right over my head not 15 feet high, and; stingrays appeared in shallow water right next to the shoreline. You can see a 15-inch-wide one of those at http://www.backyardnature.net/n/08/081229sr.jpg.

    First of all, are stingrays "fish?" In the old days when textbooks spoke of "the Class Pisces," or "the taxonomical Class of Fishes," it was easier to say. However, nowadays gene sequencing has revealed that kinds of animals we think of as fishes are so scattered throughout the phylogenetic Tree of Life that, if we consider any one branch including all those taxa, that branch will include certain four- legged animals that definitely we don't think of as "fish." In other words, the concept of "fish" isn't sound in a technical, taxonomical sense.

    However, using the term "fish" in a traditional way, we can say that ray-fish are indeed fish. They're "cartilaginous fish" (as opposed to bony fish), which groups them with sharks and skates.

    What's the difference between a stingray and a Manta Ray? One definition of a stingray is that it's a member of the Stingray Family, the Dasyatidae. Manta Rays belong to this family, so manta rays also can be regarded as stingrays. Manta rays might be defined as species in the genus Manta, a genus famous for including some of the largest rays. One could say, then, that all mantas are stingrays, but not all stingrays are mantas.

    Stingrays bear razor-sharp stingers, or saw-toothed spines, which grow from their whip-like tails like fingernails. Two grooves containing venom-secreting glands occur below the spines. Stingray "wings" are actually large pectoral fins. Many ray-fish lack stingers. Their rear ends look like the rear ends of regular fish. In fact, when you have a lot of pictures of cartilaginous fish before you, you can arrange them so that there's a fairly smooth gradation from cylinder-bodied sharks to flat-bodied ray-fish.

    I'm unsure which species appears in my photograph, but I'm leaning toward calling it the Southern Stingray, DASYATIS AMERICANA, despite all the pictures I've seen showing that species as much darker than what's in my picture. Southern Stingrays are common from southern New Jersey south to Brazil. They get up to 5-½ feet wide (1.7 m) so maybe ours is a baby.

    While researching my stingrays I came upon some pictures of another species of ray migrating, and those pictures are worth seeing. Take a look here.

    *****

    FLAME BOX CRAB
    On Christmas morning I found at the water's edge the four-inch wide Flame Box Crab, CALAPPA FLAMMEA, shown at http://www.backyardnature.net/n/08/081229bc.jpg.

    He was freshly dead, and I have no idea what disaster had befallen him. But I'd been looking for such a crab picture, because if you just walk the beach during the day you get the impression that about the only crab out there is the Ghost Crab we talked about earlier.

    But, the "Reef Creature" field guide on the table in the Reception Room contains pages and pages describing hermit crabs, porcelain crabs, mud crabs, box crabs, pea crabs, swimming crabs, clinging crabs, teardrop crabs, sponge crabs and hosts of other kinds of crabs as well. As suggested by our Flame Box Crab, those species come in every imaginable shape, color, skin texture and adaptation. Our dead Flame Box Crab is a good, randomly encountered representative of the impossibly beautiful offshore world that, when you experience it, enlarges you, makes you happy, and fills you with more profound insights into what's going on with Life on Earth.

    The Flame Box Crab occurs from the Caribbean area and Bermuda north to Massachusetts. The field guide says that it inhabits sand flats and areas of mixed sand and rubble, and often buries in sand. Marcia says that they're often seen when you snorkel, and as you pass over them they often just sit there, maybe depending on their camouflage.

    *****

    SEA-LAVENDER
    An extremely common, grossly underappreciated and unnoticed shrub on sand facing the ocean here is shown at http://www.backyardnature.net/n/08/081229tf.jpg.

    In English this dense, waist-high, woody, fuzzy-leafed, gray-green shrub can be called Sea-Lavender or Sea-Rosemary, though Lavender and Rosemary reside in the Mint Family, while this plant, known technically as TOURNEFORTIA GRAPHALODES, is a member of the Borage Family, the Boraginaceae. Maybe you'll believe it's a Borage Family member when you see its flowers at http://www.backyardnature.net/n/08/081229tg.jpg.

    Don't the small flowers' shapes and the way they're stacked along the upper side of a slender, curling stem-branch remind you of Forget-me-nots, who are members of the Borage Family?

    The plant in the picture grows atop a ridge thrown up by machinery keeping sand off the road. Notice the long, pale "sucker stems" at the bush's base. On the beach these growths catch windblown sand and are quickly buried, giving the impression that the plant is a thicket. Leaves inside the plant tend to turn black, shrivel and fall off, causing the bush to be fairly open and dark inside, while presenting a dense, pale surface to the harsh external world. You can imagine that birds, crabs and other critters find wonderful shelter here.

    Sea-Lavender has been so conspicuous on so many sandy beaches I've been on in the Yucatan that I figured the species must be one of those very vigorous, very widely distributed species, almost like Coconut Palms. However, on the Internet I read that Sea-Lavender occurs only in the Caribbean area, Bermuda, the southernmost tip of Florida (where it's listed as endangered), and here in the Yucatán.

    Ecologically, Sea-Lavender has been called a "frontline species" because on the beach it's often the first large plant you run into as you walk away from the water. This plant demonstrates a remarkable ability to survive in full sun and in constant wind carrying salt spray. Sea-Lavender flowers year-round, but blossoms most prolifically during the winter dry season. Its flowers emit a modest sweet, perfumy fragrance, and it's a wonderful thing to be walking across the beach's sizzling, blinding sand and smell such a delicate perfume wafting from such a non- nonsense-looking plant.

    Sometimes the species is placed in the genus Argusia.

    *****

    WHERE I AM ON GOOGLE EARTH
    Fred in California has taught me something neat about Google Earth, so now I'll share it with you. First, IF you have Google Earth installed on your computer, take a look at where I am right now by going to http://www.backyardnature.net/n/08/081229.kmz.

    The above address opens a page on Google Earth showing a yellow thumbtack stuck where I am.

    Once you have this or any other Google Earth image on your screen you can go to the top of your screen and click on the envelope with a blue M across it. Then you'll have a choice of three kinds of email attachment you can send to others, so that they can see the same image. If your recipient doesn't have Google Earth installed on his or her computer, choose the first option, which is to send a normal image file in JPG format.

    If the recipient does have Google Earth installed and you want them to be able to explore the area around the image or maybe see it closer, choose the second option, "Snapshot of 3D View." More advanced users will understand the third option.

    Once you choose your option, click on "email," then choose whether to send the email with your Outlook Express or Gmail accounts. If you don't have Outlook Express or a Gmail account, I guess you can't do this.

    When the recipient receives the mail, the attached KMZ file can be opened and your thumbnailed location can be viewed on Google Earth. You can also save the file to your own computer and attach it to other mails, or upload it onto the internet the way I have so that lots of people everywhere can see you are.

    *****

    WIND
    I've slept in my tent on the beach every night since I've been here. This week it's been particularly windy, causing my tent's nylon walls and rainfly to shake and flap all night long. Awakening in the night I hear waves crashing and the Chit Palms' semi-brittle fronds clacking and scraping against one another. Whooshing, whistling wind piles sand against my tent's windward side. Rain showers come and go all night peppering the nylone. On Christmas Eve a tremendous roar during a storm awoke me. Marcia the hotel owner says it sounded like a waterspout hitting the beach, though it did no damage.

    At dawn, particularly large, long-bodied mosquitoes encrust my tent. Toward the east, slate-gray, raggedy clouds with rain beneath them march toward shore shepherding rank after rank of silvery, choppy waves before them, offshore currents deflecting the waves downshore. While packing my tent I see in the sand that crabs have left leg-scribblings all around.

    Carrying stuff to the hotel before starting my jog, my head reverberates with wind-roar/ tent-flapping/ wave- oscillating-and-crashing/ frond-scraping/ purple- cloud-oncoming sensations and those crab scribblings in shifting sand might as well have been hysterical, cuneiform script expressing my own effervescing, unanchored state of mind.

    On that walk back to the hotel, every morning I am visited with the following insight, or revelation: That in this life any sense of security or permanency is dubious, if not outright illusionary.

    But, as soon as I understand this, like a reflex, I also ask myself of what good it does to have insights like this. Usually by the time the hotel's dogs run to greet me I've forgotten why I'm thinking about revelations in the first place.

    I'm just glad to have awakened on such a gorgeous morning, to have slept through a whole other windy night, and to have dogs so happy to see me, just because it's a new day, and we're all feeling pretty good and still liking one another.

    *****

    Best wishes to all Newsletter subscribers,

    Jim

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