Return of a Native

From behind the steering wheel of a slow moving car they look more like deer than anything else: light brownish-grey moving along a ridge or down the slope of Santana Mesa on Ranch Road 170. They are usually alone or in small groups of maybe 3 or 4, running effortlessly in the desert heat. A closer look reveals a compact, muscular animal with horns, not antlers. On a mature ram those horns are large and curve back over the ears, then arc downward before curving back up to about eye level (The ewes have horns but they are only semi-circular, not reaching the size and mass of a ram’s horns). Their white rumps quickly distinguish them from the aoudads that roamed these mountains for decades. Even a quick glimpse is enough to give you a rush: they are the big horn sheep, the native has returned.
Just before Christmas of 2010, dozens of desert bighorn sheep (Ovis canadensis Nelsoni) were released in Big Bend Ranch State Park, achieving a new milestone in the effort to return bighorn sheep to their natural place in Texas. The release included 12 rams and 34 ewes (many of them pregnant). Radio collars were affixed to thirty of the animals before their release so their location and activities could be monitored. These mammals were all but extinct in Texas by 1960. Today their future looks considerably brighter.
Since 1954 an international coalition of organizations has endeavored to bring back this magnificent, highly-adapted desert mammal. Consisting of federal, state, and private conservation entities the consortium conducted extensive studies and supported scientific research on both sides of the Rio Grande in an effort to fully understand the conditions of the desert the big horn once ranged across.
It was not an easy process. Indiscriminant hunting and diseases introduced by domestic livestock and introduced wildlife worked together to drive the big horn sheep to the brink of extinction. It has taken research in epidemiology and well as ecosystem studies and habitat analysis to understand the needs of the desert big horn sheep. The financial demand of all these studies was primarily met by private conservation groups and by hunters paying for special hunting permits.
The big horn sheep seems to be ideally suited for the desert environment of Big Bend State Ranch. Its stocky build allows it to conserve energy during cold nights of the desert winter. Its body temperature can fluctuate several degrees daily as the animal goes from a cool night to a harsh summer afternoon. When the heat of late spring and summer really bears down, the animal seeks shade in rock overhangs, caves and the few trees it can find. Padded hooves and its ability to leap 20 feet straight up allow the animal to climb in its steep rocky terrain. Its keen eyesight allows it to spot lions and coyotes and cover the mountain habitat at speeds of 15 miles per hour, putting plenty of distance between it and its would be predator.
Even in the midst of a harsh drought the big horn can go days without visiting a water hole, getting some moisture from its food of leaves, twigs, yucca, cacti, and the few grasses it can find. The animal can lose as much as 30% of its body weight to dehydration and then rapidly rehydrate when it does find water. To help in its survival in its new habitat, water guzzlers have been placed at strategic locations around the release site to provide a few extra “water holes” for the desert’s new arrival. Guzzlers are simple structures consisting of a sloping roof that allows any moisture, whether dew, frost, or rain, to trickle down slope into a collection barrel, creating an artificial water hole. It doesn’t take much moisture to help the big horn survive.
For most of the desert year rams and ewes lead separate existences, staying in small groups of the same sex and foraging with no concern for the other sex. All of that will change during the mating season. This is when the rams will challenge each other for access to the females. During fall and early winter rams will gather up a small herd ewes (usually no more than 10 to 12) and fight with other rams for mating rights. A ram of about 7 years of age should be large enough and strong enough to mate with whatever ewes he wants and is willing to charge any rams in his way. From distances of about 10 feet away, rams run full tilt into each other, colliding at full speed in the horns. After each collision they stand looking slightly dazed before repeating the collision. At some point one of the rams walks away from the battle while the other remains with the ewes
The anatomy of the desert big horn is designed to survive such head bashings with a double-layered skull richly supplied with bone struts connecting the two layers and providing a cushion to absorb the blows from other rams. The spine and skull are attached with thick tendons that help the neck recoil from the impact.
Lambing season is usually from early winter through spring, depending on the time of mating. Gestation period is about 175 days and the ewe may deliver up to 3 lambs. This is the time of greatest danger to the big horn and the ewe will try to find a steep isolated area to give birth and care for her lambs. Eagles, bobcats, and coyotes, if they can reach the birthing site, will prey on the newborn sheep, but after as little as a week the lambs can follow their mom almost anywhere with ease. After just a few weeks the lambs form their own groups and return to the ewes only for nourishment. After four to six months the lambs are completely weaned.
As ruminants, desert big horn sheep can gain nourishment from even the dried grasses growing on the desert mountainsides. Mostly diurnal in the winter months they will feed on grasses on and off throughout the day, resting and regurgitating the meal for complete digestion. As the grasses become more scarse the sheep will browse on desert scrub vegetation, eating leaves and twigs until seasonal rains bring back the desert grasses.
With the changing desert climate it is hard to know what is in store for the newest herd of Texas big horn sheep. For now, it is exciting to know that they are out there and, for the time being, surviving in the Big Bend. (Photo Credit: TPWD/Earl Nottingham)

TEST POST

TEST POST

MONSOON SEASON

High winds, incredibly low humidity, and fear of wildfire have created a tension throughout the Big Bend that will only be relieved by summer rains. In an ideal world they would be spring rains, falling tomorrow (or even tonight) but the probability of that happening in the Big Bend is almost nonexistent. We have entered the driest season of our desert year. The seasons and months are not the same as those we learned about in grade school with April showers bringing May flowers. Our year has winter and spring rolled into a long dry period with gradually increasing temperatures. This dry period will end with the beginning of the monsoon, a weather pattern that brings over two thirds of the yearly rainfall to the deserts of the Southwest, beginning, with any luck, in early July.

The word monsoon is derived from the Arabic word mausim, meaning season. We use it to refer to the weather pattern that brings our rainy season. These rains result from a large-scale atmospheric change in wind direction as a result of intense summer heating in the tropics. As the air over land becomes hotter it becomes less dense and rises, creating an area of low pressure that then pulls moist tropical ocean air over the land. This causes changes in wind direction, moving this moisture rich air toward the deserts of North America. As the humid air rises with the heat of summer it condenses into clouds that bring us rain. Prior to this change the Big Bend suffers from low humidity and very high temperatures from late April on into July. Occasional thunderstorms can break through the heat of this time but the rainfall they deliver is generally too little to do much good. The temperatures continue to rise as the days increase in length and life in the desert retreats to the shade.

Our monsoon rains are actually Mexican in origin with most of the moisture-rich air being drawn up from either the tropical Pacific or the subtropical Gulf of Mexico. Such rains can come from the southeast, the southwest or the south, sometimes simultaneously! As the rains move further north from Mexico they lose strength and deliver less rainfall: a hundred mile difference in distance north can cut rainfall by one half. By watching rainfall patterns in Mexico it is possible to predict the arrival of rainfall to the Big Bend. However, it is also important to remember that predicting weather is considered by some a fool’s folly! Sometimes the monsoon season is not as productive as we would like. In 1994 Shafter had one of its driest years with 2.85 inches of rain: nothing fell until May and then nothing after July until 0.88 inches fell that December. Our wettest year was 2004 with over 20 inches of rain, most falling as monsoonal rains. The monsoon begins shortly after the summer solstice, but the rains that fall are scattered. While some places receive large amounts of rain, others receive very little. When Shafter had its wet year of 20+ inches, El Paso had 2.42 inches for the entire year. True, we are a little further south than El Paso, but that is a significant difference in rainfall.

Although rains do sometimes fall in late autumn, winter, and early spring these, technically, are not monsoonal in nature. They are usually the result of weather fronts moving into the area from the north and/or the west. These fronts gather moisture over cool Pacific waters and must be carried by powerful upper level winds to make it this far inland. Although any rainfall is welcomed by desert people, these storms do not usually provide much rainfall. The plants and animals of the desert southwest, however, have adapted to the moisture rich monsoons of summer and for now are just waiting out the heat.

OCOTILLO

It was a young boy in Boquillas Canyon who formally introduced me to the ocotillo more than 40 years ago. I was walking into the canyon and ahead of me was a young man also walking into the canyon. From maybe 20 feet behind I watched as he reached up to a clump of dazzling red flowers at the end of what appeared to be long, dead sticks and pulled a few off. As I walked by him I stopped and watched as he bit off the base of each flower and sucked out the nectar. Then I reached up to get some flowers and repeated his actions. He laughed at me and then I laughed at him. It was like sucking up nectar from a honeysuckle, maybe even a little sweeter. We then spent the better part of the afternoon walking among the flowers, laughing and sucking out nectar. It was a fine day. At that time I spoke little Spanish but managed to learn a lot about the ocotillo and the roles it plays in the Chihuahuan Desert from this young man.

Few plants can play more on the imagination than the ocotillo. In form it resembles nothing so much as a giant bouquet of dead sticks branching out at ground level and sending as many as 50 stems from three to twenty-five feet into the air. Each stem is armed with spines along its length, making it a rather formidable plant. For most of the year we see only these bare stems, but after a good rain, short, green leaves appear. These are about an inch long and cluster at the base of the spines. When arid conditions return the leaves are quickly shed, preventing the loss of too much moisture from the plant through the leaves. The ocotillo also produces another type of leaf. During its growing season smooth green leaves appear on the new growth. These leaves will curve inward near their bases and change from a soft petiole to a hardened sharp spine one-half inch long. In only a few other plant families do spines develop from leaves.

The ocotillo is well adapted to desert life and seems to prefer the arid gravelly foothills and limestone ridges where little else grows. They may be found as widely spaced individuals or in a large gathering covering several acres. The plant is protected from dryness by a waxy sheath under its bark. The root system is shallow, widespread, and sheathed with a corky substance that enables it to quickly absorb what little moisture may penetrate the ground. It is a sturdy plant, well equipped to survive in the harsh environment of the Big Bend country. Where its only enemy is, seemingly, the wind which will occasionally topple the plant. I have seen woodpeckers pecking at the stems of the plant but only a few times.

Since the ocotillo grows only in the Chihuahuan and Sonoran Deserts it is probable that early settlers to the Big Bend had never seen the plant before. A large number of common names were used to describe the plant, including: coach whip, Jacob’s staff, and candle wood. Ocotillo was an native American name for the plant and seems to be the most popular name today. A few other names, such as vine cactus and candle cactus, gave the misleading impression that this plant is a member of the cactus family. Although it was readily apparent to the botanist that the ocotillo was not a cactus (cactus do not develop leaves after a rainy season), they really didn’t know how to classify it. Eventually they decided to place it in its own family of plants which consists of a few different species of ocotillo and the boojum tree of Baja California. In the spring, whether there has been any rain or not the ocotillo usually blooms. Bright, flame-red flowers cluster about the tips of the spiny stems. There are faintly fragrant with sweet, viscous nectar. There may be as many as 300 flowers clustered on a single stem (though the usual number is about 120). Some plants have as many as 500 clusters of inch -long flowers. After the flowers wither, the seed pod matures, eventually splitting open at the top to reveal silky white seed, each with a long fringe of spirally thickened hair. The wind will disperse these so that they can germinate and produce new plants. The process may be repeated several times during the year because this plant is in tune with rainfall, not seasons.

Man in the Big Bend found many uses for the ocotillo. The seed could be eaten, the flowers made a soothing tea. A poultice from powdered roots relieved pains of arthritis and rheumatism. The wax found under the bark of the plant was used for tanning hides. Bundles of dried ocotillo stems were used as torches, the wax in them producing a bright flame. This same wax was used by later settlers as a furniture varnish. The ocotillo was an important building material, whether woven into walls or laid flat and covered with mud for a roofing material. The plant was, and still is, important as a fencing material, often the cut stems, when placed in the ground, take root to provide a living fence, leafing out after summer rains and then blooming.

Today ocotillos are disappearing from the Chihuahuan Desert as ranchers, seeking a cash crop, sell their ocotillo to landscapers. Trucks loaded with thousands of pounds of ocotillo plants can be seen leaving the desert every spring, making our desert just a little bit more deserted. I am glad ranchers have an income, and I’m glad others throughout the country find the ocotillo attractive. But this plant is part of the Chihuahuan Desert so I hope some will always remain.

DANGER!

My husband and I went walking the other day, another spectacular day in the Big Bend country. As we headed out on our hike I warned my husband to keep his eyes open, it was a particularly beautiful day for encountering one of our least favorite neighbors, the rattlesnake. They like temperatures in the same range that we do, around 75°F, give or take a few degrees. They also like sunlight after a cool morning; it helps them warm up for the day. We walked along the middle of a rocky ranch road, looking at the ground often while enjoying the singing of the birds.

At one point I saw a beautiful acacia in full bloom and moved closer to see which of the many desert acacias it was. Yes, I looked under the bush before getting very close, no, there was no rattlesnake. There was one close by however, and it began rattling loudly before I got within 10 feet of it. I appreciated the rattled warning so I did not disturb the snake any further but moved away, letting it calm down. It probably calmed down before I did!

It is the rattle that makes the rattlesnake so interesting to people (and it is the bite that makes the rattlesnake a feared member of our environment). The Papago people of Arizona tell an interesting story about the origin of the rattle. When Elder Brother first created the animals, to each he gave something unique: the beaver received a flat tail, the coyote was given cunning, to the pronghorn was given fleetness. The rattlesnake was given his rattle by Elder Brother as something he could entertain himself with. When other animals were around they would ask the rattlesnake to rattle for them because they liked the sound. Sometimes the snake would be asleep and someone would come by and say. “Hey, rattle me a tune.” And the snake would wake up and rattle until the intruder would go away. This happened so often the snake was exhausted and got so he hated the rattle. One day Elder Brother took pity on the poor snake and gave him two mesquite thorns for teeth, saying that the next time the snake should bite anyone who awakened him. This tale ends with admonition that rattlers only bite those who are awakening them. The rattlesnake has evolved quite a bit from a peaceful animal with the mesquite-thorn defense. And, speaking from experience, the rattlesnake may be wide awake when it bites what it perceives as an intruder, whether it rattles its tail or not.

Undoubtedly the most distinguishing feature of the rattlesnake is its rattle and, although vipers are found throughout most of the world, the rattlesnake (also a viper) is only found in the Western Hemisphere. While many snakes actually vibrate their tails, only the rattlesnake, with its curious appendage, has the ability to produce such a nerve-shattering sound.

When the early Europeans first encountered the rattlesnake they were bewildered and more than a little cautious. There were all kinds of rumors about this unusual serpent. One of the more interesting was that the rattle was actually more dangerous than the fangs, that when it was shaken a poisonous dust pervaded the atmosphere and killed all who inhaled it. That idea didn’t last very long, but it did emphasize a lack of knowledge. Other theories about the rattle included the idea that each rattle on a snake’s tail represented a person killed or that the rattle was intended to calm and soothe the creatures of the forest, plains, and desert. My favorite Native American myth is that the snake rattles when it is having a nightmare and, if awakened, it will bite. I think that is in keeping with the Papago story.

The true purpose of the rattle is a source of speculation. Not long ago people thought it functioned as a mating call, attracting members of the opposite sex. Herpetologists (scientists who study reptiles) have studied countless mating pairs of snakes and never heard them rattle before, during, or after the fact. Another idea maintained that the rattle summoned other snakes to the rescue when one was threatened. Again, countless experiences with angry, rattling rattlesnakes proved that seldom if ever are other snakes seen. Besides, all snakes are deaf. True they react to some “sounds” but these are only reactions to the vibrations that are felt by the body of the snake. It is quite logical to assume that no snake has heard another snake rattle.

Another idea promoted by some is that the rattle is used to charm its prey, the sound does cause most animals to freeze in position but in watching rattlesnakes catching their prey, the rattle is not used at all. One respected biologist posited that the rattle had the appearance of a grasshopper and was used to attract prey. He supported this idea by the fact that he was almost bitten when he tried to catch the grasshopper. While many people find this thought amusing and somewhat crazy I don’t laugh. I was almost bitten when I thought the rattle was a scorpion and I almost stepped on it (it was evening and no, the snake did not rattle!). Yet another hypothesis states that the rattle is used to warn its prey that it is approaching danger and that it should run away. This idea defies logic. The snake would then starve to death and there would be no more rattlesnakes. No, not even close. In some areas of North America, rattlesnakes are the most common snake.

Anyone who has spent much time in rattlesnake country realizes that the snake does use the rattle as a warning, not to prey and not to protect the intruder. It is a threat intended to drive away any creature that might harm the snake. Most other animals will retreat upon hearing the rattle. With man, this threat often causes a different reaction. Most people think that not only is the snake threatening them but is a menace to anyone else that comes by. Given an opportunity, most people will kill the rattling snake.

We did not kill the snake that rattled at us from the distance of 10 feet. It was not endangering us and we considered it a good snake since it warned us to keep away. Snakes, even rattlesnakes are an important component of our ecosystems and to remove one does damage to that ecosystem. I speak from a curious position: I have been bitten twice by rattlesnakes. Once because I wasn’t paying attention and put my hand on a rock rattler and once when I was opening the door to my house and a rattlesnake bit me on the leg while it tried to hide under the door jam. I did not kill the first snake. The second snake I not only killed, I literally blew it away with 8 shots even though the first shot killed it. No one comes to my house, bites me and lives to tell about it!

Return of the Buzzards

They are another one of those signs of spring, the turkey vultures (or buzzards, as most of us call them). Their arrival in the Big Bend is not based upon any uncanny knowledge of weather patterns, they seem to be more controlled by the calendar…their own, not ours. At my house the first buzzards usually appear during the second week of March. Just a few of them come in and settle on the hills or in the trees along the creek for a night or two and then they are gone. My older neighbors used to tell me these were the scouts, checking to see if the weather was okay for the rest of group. I have my doubts about that but the larger group of buzzards (called a kettle by some), usually appears the next week. This year, right on time, scouts were followed a week later by about 50 buzzards.

Seen from a distance, as it soars through the deep blue skies of the Big Bend country, the buzzard is beautiful, a master of air currents and crosswinds, the bird banks and circles, dives and climbs seemingly without effort. The long-evolved highly efficient flight utilizes rising hot air (thermals) to soar over this vast region.

The wingspan of a four pound buzzard is about six feet. The long, wide wings allow slow flight. The long flight feathers (called primaries) are attached to the arm bone in front and extend back. Unusually large muscles control the primaries, spreading them to increase wing surface to catch updrafts, contracting them to glide down. The adjustments are constant. The bones of the wings have been modified for this effortless form of flight. The shoulder girdle is more rigid, allowing greater wing support which makes it less tiring for long-term gliding. The joints in the wings rotate freely for subtle twists and turns.

Although it is the lone buzzard seen soaring in the afternoon skies, nights and mornings are usually spent at a common roost, either in trees, microwave towers or on cliffs. Nor are they very cordial to one another. Regularly, landing birds will crash into roosting buzzards, toppling them from their roosts. This is usually accompanied by some hissing and flapping of the wings of the disturbed bird.

One group of buzzards I have watched for 3 decades numbered more than 120 when I first started watching them in the summer of 1977. Their numbers have dropped to about 50 now. I just counted the latest flock to move in at about 60 birds. But that number will decrease over the next couple of weeks as some of them will move farther north. One of my neighbors, now departed, said that today’s numbers are significantly less than when the screw worm fly caused massive death and dying of wildlife throughout the border country in the early 1950s.

When the sun rises the buzzard seeks a sun spot, usually with others from the roost. This spot may be the top of a tree or the top of a cliff. It could be a fence post or a roof line. Much of the morning is spent standing with wings extended to get the full benefit of the sun’s rays. The exact function of this activity is open to speculation, some think it aids in thermoregulation, allowing the bird to absorb warmth after a cool night in the trees. They also spend some of this time preening (grooming) their feathers and removing lice and other parasites they may have picked up during the night.

Not all buzzards we see in the sky sleep with the flock at night. Some males and females have formed pairs and gone off to raise families. The male and female choose an isolated, fairly inaccessible cliff to lay their eggs. No nest is build and the eggs are laid on bare rock. The eggs will hatch into ungainly birds covered with cottony white down. When disturbed the young will hiss loudly and clack their sharp bills. After ten weeks they get their juvenile plumage and start learning to fly and soar.

With its sharp eyesight the buzzard can locate dead and dying animals from its vantage point high in the sky. However, the bird also has large nostrils with many smell receptors, enabling it to track down smelly, decomposing foods. While their dietary predilections may seem unsavory to us, it allows them to fill an important niche in the Big Bend country as a recycler, returning nutrients to the ecosystem.

Fools, Yankees, and Mesquites

I mentioned fools and Yankees trying to predict the weather in the Chihuahuan Desert in an earlier blog but the more I think about it the less I believe it is a Yankee or a fool’s mission. I think it is human to try to predict and prepare for what is coming as far as weather is concerned. There is another saying in this part of Texas: “if you don’t like the weather, wait a few minutes and it will change”. Nobody ever seems to remember that in those few minutes, the weather can ruin you, destroy your crops, kill your stock and wreck your house. Oh yes it can…I’ve seen it done. But mostly we just try to get through the bad weather, particularly the weather that is too cold.

If you look into local lore you will find there are lots of sayings that try to describe when freezing weather ends.
As for spring with its warm, almost hot days, clear skies, high winds, does that mean spring in the Big Bend of the Chihuahuan Desert? I was preparing for a camping trip with students from Presidio High School. We would be doing water quality tests over a 24 hour period during the weekend. As I thought about spring-like temperatures. I didn’t even look at my down sleeping bag. I mean, the warm weather is certainly a harbinger of spring. As I left the house I noticed the signs of spring. Cactus wrens, cardinals, canyon wrens and doves were all calling. Yes, that is a sign of spring. As I drove along the river I saw a few wildflowers, recovering as they were from the hard winter. A few mustards dotted the road side, along with a few bluebonnets and even fewer desert marigolds. These plants do not indicate seasons, merely conditions. Considered ephemerals by botanists, these plants germinate after summer rains but don’t bloom until late fall and into winter. Their blossoms have more to do with the length of day and summer rainfall than with seasons of the year.
One plant, the mesquite, is used throughout the Big Bend country as an indicator of spring. “When the mesquite leafs out”, the saying goes,” no more freezing weather”. As we stopped at the Colorado Put-In along the river to do water quality testing, I searched for new leaves on the mesquites. Yes! There they were. Almost lime-green in color, these leaves were definitely brand new to the plant. A closer look showed that flower buds were also emerging from the tree. Great, no more cold weather! That is, if you believe in folk tales.
Buzzards know when the danger of frost is over, according to other folk tales. They never come back to the Big Bend before the last freeze according to my neighbors. I watched the sky as I drove along the river. Ravens, lots of ravens were visible. They live here in the winter, filling in for the buzzards as carrion eaters. Lots of hawks were visible, too. Possibly many of them were migrating north. I saw pyrrhuloxias and wrens, one kingfisher and lots of sparrows, but no turkey vultures. A few people had reported seeing buzzards during the back yard bird count in Presidio but they didn’t know that we have black vultures as residents throughout the year. Only the turkey vulture, noted for its red head, counts as an indicator of spring. But turkey vultures seem to be more keyed to the calendar. For years the first turkey vultures would arrive in Shafter on March 10th, long before the dangers of freezing weather have passed.
Friday night we had dinner around the camp fire and as the students talked I looked around at the different plants. Bees were busy gathering pollen from an ash tree while, birds were busy gathering bees. But ash trees are not mentioned in folk tales, neither are the bees. As darkness fell so did the temperature. I snuggled down into my bedroll, hoping it wouldn’t get too cold.

Usually cold fronts are heralded by a line of clouds in the north. As I looked out at the clear sky I saw no bank of clouds to the north. Every cold front this year has been preceded by an unseasonably warm spell, like we had just had. Why should this one be any different? By morning the temperature was at 32 degrees Fahrenheit. I was curled in a little ball, trying to stay warm until the sun appeared. As I emerged from my tent into the warmth giving sunlight I saw that I was camped near a mesquite with new leaves. So much for folktales!