The Nature Writers of Texas

The best nature writing from the newspaper, magazine, blog and book authors of the Lone Star State . . .

Thursday, April 24, 2008

Cacti Produce Some of Our Most beautiful Flowers
by Ro Wauer

There is a marvelous cactus flower in our yard near Mission Valley. I planted it several years ago, and it annually produces several magnificent blooms. The flowers, about two inches across, have golden yellow petals. And each pad has widely spaced aeroles containing grayish spines about 2 inches long. This cactus is best known in Texas as Texas pricklypear, although it often goes by its original name of Engelmann pricklypear.

The Texas pricklypear is the most common and widespread pricklypear in Texas, although botanists have identified a total of 20 pricklypear species in the state. And there are 13 kinds of chollas, closely related species with the same genus name of Opuntia. Pricklypears possess flattened pads while cholla pads are cylindrical, rounded in cross-section. Although the majority of pricklypears look somewhat alike, chollas can vary from tall species such as cane cholla and tasajillo to those that sprawl on the ground, such as dog cholla.

Cacti or cactuses, both terms are correct, are some of our favorite plants, and they can occur from the lowest and hottest areas in Texas to near the summit of our highest mountains, such as the Chisos, Davis, and Guadalupe mountains. And cacti have been divided into at least 19 groups. Easiest of these to identify is the pricklypear/cholla group, while others can be difficult, maybe because the various cactus books seldom agree. Other groups that can usually be identified include the fishhooks, living rock, star cactus, barrel cacti, hedgehogs, and nipple cacti. And too often some of the other spiny plants are misidentified as cacti. Examples include yuccas, agaves, acacias, and ocotillo.

As near as I can determine, 88 cactus species occur in Texas. And approximately 140 forms or subspecies have been identified. But these numbers are somewhat ambiguous. Cacti hybridize readily, influenced by various environmental factors, but also because few botanists can agree. For instance, our Texas pricklypear (Opuntia engelmannii) has five subspecies. And the common and widespread claret-cup (hedgehog) cactus (Echinocereus coccineus) also has five subspecies.

What is amazing to me is, that of 88 cactus species in Texas, 23 of those are endemic, found nowhere else but in Texas. Seven of the 23 are hedgehogs, six are cob cacti (genus Coryphantha), three are pricklypears, two are chollas, two are of the genus Echinomastus, and there are three unrelated species of the genera Epithelantha, Ferocactus, and Neolloydia. The non-Opuntia cactus species vary greatly, but their aeroles are positioned along ribs or on tubercles. Although most of the unique Texas cacti occur only in the Trans-Pecos portion of the state, particularly in the Big Bend and Davis Mountains area, a few are known only from the Hill Country, the Pineywoods, or the Lower Rio Grande Valley. None of the endemic species can be found along the Gulf Coast.

Cacti are native only in the Western Hemisphere, except in Alaska, Hawaii and Maine. They are as American as corn, tomatoes, tobacco, and potatoes. But today cacti can be found almost worldwide, having been introduced elsewhere as early as the Columbus voyages to the New World. By the 1800s, cacti because so popular in many parts of the world that a number of cactus trading companies evolved, and propagation of cacti became big business. The cactus hobby continues today, and botanists are still trying to understand what plant is what. However, since the use of DNA, those relationships are becoming much more precise. Soon it will be time for the plant taxonomists to reach agreement. But in the meantime we can all enjoy the short-lived cactus flowers for their beauty.

Thursday, April 17, 2008

Chimney Swifts, Our Aerial Acrobats
by Ro Wauer

Last week I lifted off the metal chimney top that I install each fall. This invited chimney swifts back into our chimney for another season. And just like every other year, within a few days we could detect these little birds again taking up summer residency. It is one more pleasure of enjoying birds in South Texas!

Chimney swifts, one of our neotropical migrants, are widespread summer residents in Texas as far west as the Pecos River; they are less common in far West Texas and the Lower Rio Grande Valley. But as numerous as they are in Texas, and as closely associated as they are with people, for some reason they remain one of our most misunderstood birds. Perhaps that is largely due to their use of the dark interior of chimneys and other chimney-like structures for roosting and nesting. Perhaps people who fear bats have the same fear of other species that retire to the “dark side.” But this is silliness. Chimney swifts are not only one of our most fascinating birds but also one of our most beneficial species.

Like swallows and bats, chimney swifts obtain their food and water in flight; their diet consists primarily of flying insects and spiders on silken threads, and they skim water surfaces to drink. Ninety-five percent of a chimney swift’s diet consists of small insects, notably a wide variety of flies, and also ants, wasps, and bees. Swifts are the most aerial of all our birds and rarely fly alone; they usually feed in flocks of a few to many individuals. This habit probably helps them discovered insect swarms more readily than when searching alone. During migration, chimney swift flocks may number in the hundreds. Chimney swifts have been described as “flying cigars” due to their streamline body shape. They spend the vast majority of waking time in the air – feeding at various elevations, depending upon where they find the most flying insects, including the edge of thunderstorms, and courting with “V-ing” displays (wings held overhead in a V pattern) and amazing aeronautical skill.

At fist glance, a swift may be misidentified as a swallow, due to its similar behavior of feeding on the wing. But swifts are not swallows at all. They are members of the same order of birds as hummingbirds, the Apodiformes, the name derived from the Greek for “without feet.” That is a misnomer, however, because they do have feet, and although a swift’s feet seem tiny and weak, they are strong enough for birds in flight to break small twigs off trees for nesting material. Like hummingbirds, swifts are able to enter a state of torpor, their body temperature dropping as much as fifty degrees Fahrenheit for several hours at night or even for days during extremely inclement weather.

Another chimney swift habit that is out of the ordinary for birds is their use of chimneys for nesting; they once nested only in dark tree trunks and similar natural cavities. They now build their half-saucer-like nests on the inside walls of chimneys, cementing tiny twigs together and to the walls with gelatinous saliva. A nest described by John Tveten in Houston contained 130 twigs about the thickness of a toothpick or matchstick, and “all laid parallel along the longer axis of the nest, forming a half-saucer about four inches across and two inches deep.”

Only one nesting pair uses any given chimney, although the same chimney may hold several additional birds. These other birds may be either helpers – immature individuals that help the adults with various activities – or an unrelated roosting flock that occupies another portion of the chimney. The two to four nestlings are unable to feed themselves until 28 to 30 days old, so they are fed by their parents, which come and go as required. At this stage in the chimney swift’s life, their comings and goings to feed the young produce odd and strange sounds that, unless one is aware of what is taking place in the chimney can be rather frightening. But our chimney swifts are very welcome to share our home. And they are missed once they depart in summer for their wintering grounds in South America.

Monday, April 14, 2008

David Taylor has been a friend of the Nature Writers of Texas website for a couple of years now, recently producing an Anthology of Texas Nature Writers, and hosting the just finished Texas Nature Writers Conference. He's sent out a notice about his newest venture the book of poetry Praying Up The Sun. Here some info on it and notes about a couple of readings. Be sure to check it out . . .

My new book of poetry Praying Up the Sun is now available from
Pecan Grove Press.
Here's the link to the web page:
http://library.stmarytx.edu/pgpress/authors/david_taylor/index.html

Here's the link to Amazon:
http://www.amazon.com/exec/obidos/ASIN/1931247501


Also, I'm giving the first reading of it this Saturday. Drop by if
you have the time and are in the area.

On April 19 at 7:00 PM, Salon Mijangos, 1906 S. Flores, San
Antonio, will host a reading by poet David Taylor and fiction
writer Andrew Porter. This event is free and open to the public.

David will read poems from Praying up the Sun (Pecan Grove
Press 2008)

David Taylor, a specialist in environmental literature, teaches
in the English Department. He has published poetry and creative
non-fiction essays in such journals as Borderlands, ISLE,
Southern Poetry Review, Environmental
History, and Mountain
Gazette
. His latest publications are a collection of poems entitled
Praying Up the Sun
(Pecan Grove Press, 2008) and Pride
of Place:
A Contemporary Anthology of Texas Nature Writing
(UNT Press, 2006) a collection of essays about our connection
to place and how it defines and informs us. He edited South
Carolina Naturalists: An Anthology, 1700-1860
(USC Press
1998) and co-authored Lawson's Fork: Headwaters to the
Confluence
(Hub City Press, 2000). He was featured at the
2006 Texas Book Festival.

Thursday, April 10, 2008

Bird Songs, Another Measure of Spring
by Ro Wauer

Each spring, when our resident birds begin courtship and the neotropical migrants pass through our area, bird songs again become magic. But it also is a time that taxes my memory, trying to recall what bird song belongs to what species. Although songs of the full time residents, such as cardinals, chickadees and blue jays, are set in stone, those of the birds that pass through only in spring often are difficult to remember. I think that I remember better years ago before I got interested in butterflies and that new information managed to eliminate the other. Maybe it’s something else.

Long ago when I first paid much attention to bird songs, I began to memorize their songs using mnemonics. For instance, the mnemonic used to describe a common song or call of a bobwhite is “bob-white.” Blue jays sing “jay, jay, jay.” American robins sing “cheerily-cheery-cheerily-cheery,” but they also are known in song, when the “red, red robin come bob bob bobbin along.” Carolina chickadees sing a whistled “fee-be, fee-bu.” Tufted titmice whistle “peter, peter, peter.” The Carolina wren has a song we all recognize as “teakettle, teakettle, teakettle.” Our white-eyed vireo sings “quick-with-the-beer-check.” And what about the cardinal’s song? It sings “what, cheer, cheer, cheer, cheer, chee, cheer, whot, whot, whot,” or “birdy, birdy, birdy.”

The use of mnemonics is most useful when walking through the woods that echo with the songs of a dozen or more neotropical songbirds. Many of these songbirds stay up high and rarely come low enough to see well. So it can be important to know that a red-eyed vireo sings “look up…see me?... over here… higher.” Eastern wood-pewees sing a plaintive whistled “pee-ah-wee, pee-err.” And blue-gray gnatcatchers sing a lispy “spee, spee, spee.”

The vast majority of Texas birds possess a song, although fewer than half of the almost 9,500 known bird species world-wide actually sing. And many species possess a repertoire of songs, often singing different songs in order, one after the other. This behavior can be confusing. Our mockingbird, for instance, has as many as 150 songs, while a brown thrasher, only found here as a migrant or uncommon winter visitor, can sing more than 3,000 song types. A European starling’s repertoire may include only 67 song types. And many wrens, especially the tropical wrens, often sing duets, so that one individual begins the song and its mate ends the song. It is commonplace for many birds, such as our Carolina wren, to sing a song that is repeated by another Carolina wren some distance away. Each is proclaiming its territory. Songs also serve to attract a mate or to convey a message, such as the presence of a predator.

How many songs do birds sing in a single day? That varies with the species. Ornithologists Margaret Nice recorded 2,305 songs in a single May day from a song sparrow. She reported a black-throated green warbler that sang 1,680 songs in seven hours, and she estimated that on a typical day of sixteen hours, he would have sung more than 3,000 songs. But the North American winner is the red-eyed vireo. Ornithologist Harold Mayfield recorded a Michigan red-eyed vireo which sang 22,197 songs in a day.

But whatever the message or how many songs can be sung in a day, to most of us who enjoy birds, it is the song’s acoustical quality that we most enjoy. For many of us, it would be an empty world without the songs of birds.

Thursday, April 03, 2008

Are You Ready for the Spring Monarchs?
By Ro Wauer

Already many of the monarch butterflies that have spent their winter in Mexico are passing through Texas in their spring migration. Texans should be seeing these marvelous creatures during all of April and May. Their second or third generation will continue their northward movement until they eventually reach the northern edge of their range, often as far north as southern Canada. Three or more generations will emerge each summer, each with a life span of four to five weeks. Those that emerge in late summer are not reproductively mature, so they represent the late season monarchs that migrate south through Texas to wintering sites in the mountains of Michoacan in central Mexico. There they gather in huge numbers to await springtime when they will begin their northward journey.

Monarchs are one of the “milkweed butterflies,” species that depend upon milkweeds for their larval foodplants. The similar but smaller queen butterfly is another of our milkweed butterflies, and one that we usually find throughout the summer and fall months. The milkweed butterfly name is derived from the fact that the females lay eggs only on milkweeds, although adults obtain food from a wide variety of flowers. Monarch eggs hatch in three to five days with warm temperatures, although eggs in cooler temperatures may not hatch for as many as 20 days. Upon hatching, the tiny caterpillars feed on the milkweed leaves, and as they grow from tiny caterpillars only few millimeters in length to about two inches they shed their skins five times, each known as an instar. The last instar fastens onto a safe place and pupates into a shiny green chrysalis, and in about ten days an adult monarch emerges.

One cannot help but marvel at monarchs, a seemingly fragile creature that can make a 3,000-mile fall journey from southern Canada to Central Mexico. The fall migrants generally follow one of two routes, either along the Gulf Coast or through central Texas. The largest numbers occur in wide belt from San Angelo to Bracketville to Eagle Pass during the second and third weeks of October. Those that pass through coastal Texas never reach the same high numbers, but some years are much better than others. But springtime monarchs are far more numerous along the Gulf Coast, passing through the Golden Crescent. They may fly at various elevations, usually in a gliding flight pattern. They often stop at flowering patches to feed, or when females discover milkweed plants they may take the opportunity to lay a single egg or a few eggs on the milkweed leaves. Once that has been accomplished, they continue northward, although they rarely survive much longer. It is that next generation that will continue their northward movement.

Although more than 100 kinds of milkweeds occur in North America, only a few can be found in South Texas. All of the milkweeds, almost all of the genus Asclepias, possess white sap that contains a toxic alkaloid. It is this material that milkweed butterflies absorb when feeding, either as a caterpillar eating the leaves or as an adult sipping nectar, that gives them toxicity that predators shun. A predatory lizard or bird, upon catching a monarch, will spit it out as soon as possible. And a few other butterflies, such as the viceroy, mimic monarchs. Viceroys are very similar in appearance to monarchs, but are not toxic. Viceroy caterpillars feed on willows, not milkweeds.

For those of us with gardens, now is the time to plant some milkweeds. The two species most commonly planted in our area include the native butterfly weed (Asclepias tuberose) and the nonnative tropical milkweed (Asclepias curassavica). Like feeding birds, providing a few milkweed plants can provide true satisfaction, knowing that we have helped the monarchs along their journey. Besides, we can entice them to stay a bit longer so that we can enjoy their beauty and appreciate their unique odyssey.