A Secretive Nomad: The Masked Duck
A male Masked Duck with an injured foot joined a male Common basilisk lizard lakeside at Finca Cantaros in Linda Vista de San Vito, Costa Rica
Sometimes they arrive at our marshy pond at Finca Cántaros in late January, sometimes in February, and this year some individuals came in both March and April. These highly unpredictable fowl are the Masked Duck. They stay a few weeks or a few months. In the literature, these small ducks are called vagrants, erratics or nomads at the margins of their range. They are not considered migratory, and their unpredictability depends on prospects for food and water. They are stifftails—ducks with long, spiky tails that were described and named Oxyura dominicus in 1766 by Carl Linnaeus, the “Father of Taxonomy”. In 1880 American ornithologist Robert Ridgeway determined Oxyura dominicus was different enough from its closest relative, Oxyura jamaicensis, the Ruddy Duck, that it should have its own genus. The handsome Masked Duck is now known as Nomonyx dominicus.
Such a long history, but in 2015, much is still unknown about the Masked Duck in the Anatidae family of ducks, geese and swans.
Female Masked Duck, left; male Masked Duck, right, on Laguna Zoncho. Photo: Marco Tulio Saborio
Though the Masked Duck has a wide range in the Neotropics, they are considered scarce in all locations. Inhabiting small lakes with marshes, freshwater mangrove lagoons, and even rice fields from northern Argentina through South America, Central America, and the Caribbean to North America, they don’t gather in large groups to reproduce. The only occasional breeding and nesting locations actually documented have been on the Gulf Coast of Texas and in Barbados. We learned from the San Vito Bird Club that the only sighting of the Masked Duck in southern Costa Rica this year has been on our own Laguna Zoncho at Finca Cantaros.
Laguna Zoncho, a wetland that attracts aquatic birds primarily in Costa Rica’s south Pacific dry season, December to April. The lake has been dated by sediment testing; maize pollen found is 3250 years old indicating people have lived around the lake for at least that long.
Because the Mask Duck is so rare, the president of the San Vito Bird Club reports their arrival at Finca Cantaros to eBird, an international repository for observations. Some birders come to our nature reserve just to see them.
The Masked Duck likes open water when diving and gleaning greens from our aquatic plant, Elodea, but is never far from marsh cover. When staying out of sight, they may behave like rails or like our White-throated Crake, making pathways or using preexisting tunnels in the grasses, foraging for seeds, roots, insects and small crustaceans. From what we observe they are shy upon first arrival, flying to the opposite side of the pond when people pass by on the lakeside trail, but they do slowly lose some of this skittishness if people are quiet.
Common Gallinule with male Masked Duck, left; female Masked Duck, right.
In our summer (December through April) Elodea provides food not only for the Wolf ciclid, a lake bass, and for visiting Masked Duck, but also for Blue-winged Teal and Common and Purple Gallinule. Green Heron, Great Blue Heron, and the occasional Great Egret search for fish or insects at the edges of the pond, joined by Spotted Sandpiper, Ringed and Green Kingfisher at certain times of the year.
Spotted Sandpiper may appear at any time of year at the lake’s edge.
Data about Masked Duck is scarce. The habits of their young are termed “not well known.” The age of their first flight is “not well known.” Breeding habits are “not well known.” Their secretive behavior and nomadic wanderings make estimating their numbers difficult, so the website Partners in Flight in 2010 suggested their population was between “50,000 and 499,999” individuals. The largest number observed was about 3800 ducks on the Texas coast after heavy rains made temporary wetlands. Because their range is extremely wide, even if their numbers are diminishing due to hunting and habitat loss, they are not considered a Vulnerable species, but rather a species of Least Concern by the International Union of the Conservation of Nature (IUCN). Hunting for Masked Duck, and all wildlife, is illegal in Costa Rica. But Masked Duck hunting is legal in Texas, where hunters may bag up to six ducks per day. Hunting with dogs for Masked Duck was recorded in Cuba in 1923. Curious about why Masked Duck would be hunted, I searched the web for recipes but could only find in an International Dictionary of Food a reference to them as “highly prized” for the table.
Great Blue Heron perches above Laguna Zoncho on a Cecropia branch.
In 2009 some Masked Duck arrived on January 26 and I made a note of it. Early in 2010, on my usual 6:15 am walk, I was on the lookout for the ducks. There were Gallinules on the lake, but no other aquatic birds. Continuing my walk to a hilltop overlooking the wetland, I suddenly heard loud splashes. Five Masked Duck had arrived together, exactly the same day as the year before! They soon curled up to rest, heads under wings. A few hours later, they were eating Elodea as if their lives depended on it. I felt unbridled optimism about life on earth. I don’t know where they come from or where they go when they leave, but may Masked Duck keep finding their way, and may someone always be here, long after I am gone, to wait for them.
References
According to Stiles & Skutch, Masked Duck are also “uncommon” in Costa Rica’s Valle Central, especially around Cartago; in Guanacaste’s Tempisque basin, and in the environs of Río Frío. A Guide to the Birds of Costa Rica by F. Gary Stiles and Alexander F. Skutch, illustrated by Dana Gardner, Comstock Publishing Associates, a Division of Cornell University Press, 1989, p. 95.
Garrigues and Dean call them “rare” from lowlands to 1500 meters. The Birds of Costa Rica, A Field Guide by Richard Garrigues and illustrated by Robert Dean; A Zona Tropical Publication from Comstock Publishing Associates, a division of Cornell University Press, Ithaca, New York, Second Edition, 2014, p. 36.
See also these websites: Audubon, Cornell Laboratory of Ornithology, and Ducks Unlimited.
My friend Marco Tulio Saborio, photographer of the Masked Duck pair above, is well known for his extraordinary photographs of the birds of Costa Rica, marine wildlife, and the biodiversity of the tropics. He can be reached by email at msaborio@conexion.cr
Flower Power: Spadix and Spathe in the Araceae Family
Anthurium formosum spadix with male Eulaema (bumblebee) and amber Eufriesea (metallic bees), both in the Euglossini family, commonly known as orchid bees
An iconic leaf you often see representing the luxuriant vegetation of the tropical world is an arrowhead or heart-shaped leaf with a drip tip, coming in many sizes, iterations and venations (vein patterns), found in plants of the Araceae (“ar-ray-say-e”) family. Common names are Aroids or Arums.
Philodendron sp. climber in the forest
You may have first learned about this huge plant family in your own home, when your mother installed a large Philodendron in a corner of your living room. You had your first lesson in botany when you saw the leaves turn squarely toward the light and saw the plant quickly climb that roughhewn board wedged into the plant pot. If you are like me, you can’t remember ever seeing the Philodendron flower. In just a few weeks the Philodendron sent out various leafy tendrils, some threatening to take over your dad’s Lazy Boy. Our mothers probably cut them back before they had time to invade or to bloom.
Philodendron bipinnatifidum, a thermogenic plant at Finca Cantaros heats up to 115 degrees F, 46 C.
In the Neotropics there are more than 500 species of Philodendron; about 250 species occur in Costa Rica, 3000 species worldwide. Other major genera of the Araceae family found in Costa Rica are Anthurium, Monstera, Syngonium, Spathiphylum and Dieffenbachia.
You may already know the family Araceae from the Jack-in-the-Pulpit (Arisaema triphyllum) and another plant common in the Northeast of the USA, skunk cabbage (Symplocarpus foetidus), one of the first plants to appear in early spring. These, and all the other members of the genera listed above, have the distinctive inflorescence of tiny flowers or florets on a spadix emerging from a bract or spathe. The hooded spathe of the skunk cabbage–blotchy, brownish-purple (the color of rotten meat)–covers the spadix and opens only when the female flowers are receptive.
Skunk cabbage in full bloom in Massachusetts.
Like some of its tropical relatives, the skunk cabbage is capable of thermogenesis, a complex chemical process involving impressive generation of heat. The high temperature of the blooming spadix and its covering spathe, the first parts of the plant to appear, melts the snow above. Why do skunk cabbage and many Aroids in the tropics generate heat? Why, to promote pollination: the foul odor of skunk cabbage attracts mostly beetles and flies, and sometimes even butterflies. The heat–as much as 86 F (30 C) higher than the ambient temperature!–volatizes odors broadly and efficiently, thus attracting pollinators from greater distances.
Scarab beetle covered with pollen paste after being enclosed for hours on florets of Philodendron bipinnatifidum
Another possible evolutionary advantage for thermogenic plants is that the beetles that pollinate them prefer their warmth: beetles don’t move much until the sun shines and temperatures rise. More moving beetles in a warm thermogenic environment, protected from the elements by the spathe, with pollen nutrients to eat, means more reproductive opportunities for the plant. It seems like co-evolution at its best.
I first learned about thermogenic mechanisms from a magnificent elephant-ear-sized leaf specimen, a tree Philodendron cultivar (below) at the Wilson Botanical Garden of San Vito, Costa Rica, where I worked from 1989 to 1999. Related to my development responsibilities was giving tours to natural history visitors. What impish fun I had when leading silver-haired Elderhostelers to the robust plant when it was in full flower, a large white spadix thrusting out of its pink lined spathe. “Touch that,” I would dare one of the ladies. Her scream of shock when she put her hand around the hot spadix woke everyone who was starting to doze on the tour. A plant generating such heat always astounded and amazed the ever-curious groups, giving me a chance to explain the advantages of heat generation for pollination by the beetles. The flowers’ fragrance is pleasant in this case and carries far at full maturity.
Spathe and spadix with white florets of Philodendron cultivar at Wilson Botanical Garden.
Arum in the Araceae family, Zantedeschia aethiopica, known as Calla lily.
For those on the West Coast in Northern California and points further north, you are likely accustomed to another member of the Araceae, the common Calla Lily found in moist areas and wetlands—actually, not a lily at all, but an Arum, the Zantedeschia aethiopica. The Calla spadix has a mildly sweet fragrance but does not generate heat. Though lovely as cut flowers, Callas can spread invasively and are sometimes considered pests.
Here at Finca Cantaros, pollination events on non-heat-producing Anthurium and Spathiphyllum are busy affairs, attracting stunningly attractive Euglossine bees, commonly called orchid bees as, indeed, they visit orchids as well. The loud buzzing of the hairy, yellow and black Euglossine bees in the genus Eulaema first attracts my attention if I happen to be walking by a flowering spadix. Then I observe on the same inflorescence the more quiet amber, blue or green metallic orchid bees in the genus Eufriesea. As a photographer, I can get very close to the action: these are stingless bees. They are practically oblivious to the lens just inches away. Nothing matters to them except grabbing the chance to gorge and collect pollen, thus ensuring future flowers and the next generation of bees.
Spadix of Tabacon, Anthurium sp. with blue orchid bees.
Spathiphyllum sp. spadix being visited by green orchid bees.
Likewise, in the case of our own thermogenic tree Philodendron bipinnatifidum, scores of large nocturnal scarab beetles, smaller beetles, flies, earwigs and others arrive to dine and copulate, but it’s the beetles that do the heavy lifting of pollination.
As for all the heat-producing Aroids, there is something reassuring in the knowledge that beetles have been pollinating relatives of this plant family since the Mesozoic era, which ended 66 million years ago. We see the simple beauty of natural selection at work today in this ancient, enduring adaptation.
Anthurium flowers as shown here at Finca Cantaros are big business for the nursery trade, among the world’s most popular tropical plants.
These unidentified beetles come in large numbers to Philodendron bipinnatifidum
Anthurium formosum leaf, up to three feet long
References:
Heat-producing Flowers, by Roger S. Seymour and Paul Schultze-Motel, Endeavor, Vol. 21 (3), 1997.
Willow Zuchowski has an excellent chapter on the Arum and Philodendron Family in her book Tropical Plants of Costa Rica, A Guide to Native and Exotic Flora, pp. 354-365, a Zona Tropical Publication (2007).
Click on any photograph to enlarge it, then hit back button to return.
Emberá Drua Village on the Rio Chagres in Panama
Boys play along the Chagres River in the 320,000 acre Chagres National Park
Ever open to visiting more tropical forests, in 2010 my husband and I visited Panama City forseveral days and opted for an individual tour to the village of the Emberá Drua people in the Chagres National Park. To get there, we traveled with our guide by car to Port El Corotú, and then in a piragua, a dugout style long canoe from Lake Alajuela, which leads to the Upper Chagres River and the Emberá village. Halfway there, the boatman turned off the motor. Silently pushing his long pole into the riverbed to propel us forward, he took a narrow side river tributary through dense forest to a small white sandy shore, from which we walked under dripping trees to a lovely waterfall with a swimming hole. Epiphytic orchids seemed abundant on the trail. I was in my element. We were completely alone in this spectacular space.
An small epiphytic orchid on the trail
As a young girl I was immensely attracted to everything that jungles had to offer on TV. I think I saw most of fifty-two episodes of Ramar of the Jungle—the White Medicine Man–on Saturday morning children’s TV. There was a Tarzan series the whole family enjoyed. In 1960 I loved the film Swiss Family Robinson, and soon after was transfixed by The African Queen (originally made in 1951) on TV. In early high school, without telling my parents (because I was fairly sure they wouldn’t think the movie was appropriate for my age), I went with friends to see The Naked Jungle (1954) with Charlton Heston. What could be better than seeing hoards of army ants on the move, surrounding a mean misogynist owner of a South American cocoa plantation. The camera panned between interpersonal dramas leading to murder and the inexorably converging ants by the millions, crossing rivers and eventually…well, you’ll have to see it. (To my surprise, Rotten Tomatoes gives it an 83.)
Guessing which hand holds the prize.
Certainly I was not alone in enjoying movies about African and South American jungles, indigenous people (called “natives” back then, and usually carrying spears), strange languages, wild beasts, reptiles, deadly insects and spiders: a Google search for “jungle movies” reveals hundreds of them were made from the 1920s right up to the recent past with such films as Avatar and even Hunger Games.
All this is mere background to help explain in small part why I left a fine position in San Francisco, CA in 1988 and plunged into development work related to tropical forest conservation, research and education in San Vito, a remote area of Costa Rica. Since then I have become very comfortable in tropical forests (“jungle” isn’t a word used very often in the New World), and even planted some forest of my own at Finca Cántaros.
Homes are built high off the ground and are completely open-sided
Back to our visit to the Emberá Drua village. About fifty Emberá people moved out of the dangerous Darien Province of Panama in 1975 and formed a new community, Drua, with special dispensation by the Panamanian government to live in the Chagres National Park if they agreed not to cut down forest for agriculture and to hunt only for their own food needs. Their livelihood would become primarily reliant on tourism. The people agreed to these compromises, because they wanted greater access to health care and education for their children, as well as freedom from pressures of Colombian drug traffickers in Darien Province, contiguous to Colombia’s border.
Woman gazes at her fire in the cooking area of her home. Rough-hewn stairway to her kitchen area.
Our naturalist guide, Harry and I were in a small group of visitors who enjoyed a healthy fish and rice lunch served in banana leaves. A community leader spoke about village society, work and customs. Music followed with dancing young ladies who seemed to enjoy themselves. Of course, this was their work, but they did their best to smile throughout.
We purchased crafts, but declined body painting. We were too busy enjoying the experience of seeing how the Emberá lived: the designs of their homes, the materials with which they made their crafts, and how their children played joyfully in torrential downpours. As our boat motored away from the village shore, we envied the simplicity of their lives, imagining that all our common ancestors lived similarly, so many eons ago.
Adolescent girls dance demurely for paying guests.
Children play soccer in the rain.
Foto Diarist 