Clever Corvids

Common Raven, Corvus corax

Crows, ravens, and jays are members of the Corvidae family, or corvids for short.  Medium to large perching birds with strong bills and feet, and feathers that are predominately black or blue, they are bold, curious creatures, and are found in a wide range of habitats.  

Corvids are known for their high degree of intelligence in the bird world, especially crows and ravens.  Crows have performed as well as monkeys in psychological tests, and most employ intelligence in their daily routines, such as dropping nuts onto hard surfaces (like roads) to crack them.  Ravens can recognize groups of different sizes up to seven, and often show problem-solving insight when posed with an intriguing new task.  

Corvids are very social birds, with most living in extended family groups year-round.  Groups give the birds an ability to guard one another, and those posing as sentries can warn other birds and wildlife when predators such as hawks and owls are near, sometimes mobbing them and chasing them away.  While corvids are noisy birds with loud, often screeching calls, they are also excellent mimics of other birds, and those in captivity have been shown to mimic even human speech. During the winter, when food can be scarce and the weather harsh, corvids aggregate in large groups at abundant food sources and roost together to stay warm at night.  

American Crow, Corvus brachyrhynchos

Found primarily east of the Balcones Escarpment in our area, the American Crow (Corvus brachyrhynchos) is an all black, thick-necked bird with a straight, heavy bill and a short tail that is squared off or rounded at the end.  Their loud cawing gives them away, and many times you will hear them before you see them.  Highly adaptable, they will live in any open space that offers trees for perching and a reliable source of food.  The Common Raven (Corvus corax) is a very similar-looking all black bird, larger but more slender, and with a wedge-shaped tail.  It is found mainly in the Edwards Plateau west of the escarpment and in far West Texas.  An acrobatic flier, one adult was observed flying upside-down for more than a half-mile, and young birds are often seen dropping sticks and diving to catch them in mid-air.  

Western Scrub-Jay, Aphelocoma californica

Blue Jay, Cyanocitta cristata

While there are two species of jays in our area, they overlap only slightly in range.  The Western-Scrub Jay (Aphelocoma californica) prefers the juniper-oak woodlands of the Texas Hill Country while the Blue Jay (Cyanocitta cristata) inhabits the prairies and grasslands in the eastern part of town.  Gorgeous azure blue above with a slate gray back and light gray breast, Western Scrub-Jays lack the head crest and black barring with white patches on the wings that distinguish them from the Blue Jays.  Both species of jays have a mischievous streak, stealing other birds’ cached food and chasing off smaller birds to steal sunflower seeds and peanuts at feeders.   

Green Jay, Cyanocorax ymcas, this common resident of deep south Texas hasn't made it to Austin - yet.

In the wild, corvids are long-lived birds, often reaching over 15 years of age.  During their lives they clearly learn to act intelligently, and we have yet to determine how intelligence might be distinguished from instinct.  But the more we observe and record their behaviors, the more we can appreciate and enjoy these clever corvids!     

Dispelling Common Myths of the Ashe Juniper

Ashe Juniper, Juniperus ashei

The Ashe Juniper (Juniperus ashei), more commonly but incorrectly known as the ‘cedar’ tree, is not the bane of nature many people have come to believe.  It is as much a part of the Texas Hill Country as wildflowers and limestone.  The juniper tree can germinate on bare rock, quickly develop a thick canopy to protect the earth beneath it, and drop an enormous amount of leaf litter that can build soil and capture and hold water.  Let’s explore some of the more common myths surrounding this tree, and in the process begin to appreciate its purpose, beauty, and wildness.

Pollen produced on 'male' trees

Berries produced on 'female' trees

Shaggy bark of the Ashe Juniper

Myth #1:  The ‘cedar’ tree is not a native tree.  While you have probably heard some of the tall tales about how junipers may have arrived in Central Texas, the undisputable proof that they are native lies in fossilized juniper pollen found in our area, dating back to the last Ice Age. Additionally, in historical records dating back to the late 1600s and early 1700s, junipers are accurately described by Spanish trailblazers, missionaries, and other early settlers and explorers alike.  While native to our area, Ashe Junipers are invasive.  Naturally occurring on steep, west-facing slopes, they have spread to cover most of our terrain due to our tendency to suppress the normal wildfires that kept them within their typical boundaries.

Myth #2: The ‘cedar’ tree is a water hog.  Scientific stemflow studies have shown that the juniper does not take in much more water than any other native woody plant its’ size.  Junipers are extremely drought tolerant, and their dense canopy breaks the impact of falling rain.  This allows a thick organic litter to accumulate under the juniper, which slows down erosion and provides flash flood control. When slopes are clear-cut of juniper and native grasses cannot establish themselves, we not only lose our soil, but we may also be losing water. Eroded soil can fill the recharge cracks and limestone karsts with silt, which ultimately decreases the amount of water that percolates into the aquifer.

Golden-cheeked Warbler, Setophaga chrysoparia

Myth #3: The ‘cedar’ tree is a useless tree.  One of our endangered species, the Golden-cheeked Warbler, uses the soft bark strips of old-growth Ashe Junipers to build its nest.  Many other species of wildlife use juniper thickets as escape cover and shelter, and in the winter, its berries feed several species of birds and mammals.  Butterfly larvae, such as the Great Purple Hairstreak (Atlides halesus) and Juniper Hairstreak (Callophrys gryneus), as well as the Tortricid or Leafroller Moths, all consume the foliage.  And from a human point of view, oils provided by the juniper are used to scent perfumes and soaps, and the wood itself has been used for fuel, furniture, tools, fence posts, and just about everything in between.     

Juniper Hairstreak, Callophrys gryneus

Myth #4: Cutting down all the ‘cedar’ trees in my yard will protect me from ‘cedar fever.’ December through March is the height of ‘cedar fever’ season.  This is the time of year that juniper trees (males only, the females produce the berries) produce copious amounts of pollen, up to several pounds per tree.  Once this pollen becomes airborne, it travels hundreds of miles to reach every allergy sufferer.  Let’s face it – ‘cedar fever’ is simply a natural part of living in Austin.

In short, the Ashe Juniper helps us to define what we call ‘a sense of place.’  Combined with the wild and tumbled terrain created by our ubiquitous limestone, the character of the juniper’s twisted limbs and the smell of its foliage in the deep summer heat define the essence of the Texas Hill Country.

Jolly Holly

Possumhaw, Ilex decidua

One of the brightest colors in the winter landscape belongs to the red berries of our native species of hollies.  While approximately 600 species exists worldwide in the genus Ilex, in our area we have Yaupon Holly (Ilex vomitoria) and Possumhaw (Ilex decidua).  The first is naturally found in both dry and wet habitats, while the second thrives in generally moist woods.  Each, however, has their own unique characteristics, and they are hinted at in their scientific names.

Yaupon Holly, Ilex vomitoria

Yaupon Holly is a large evergreen shrub or small tree with small, shiny alternate leaves that have rounded toothed edges.  Little white flowers appear in April and May, followed by quarter-inch bright red fruits in fall and winter.  The species name 'vomitoria' means exactly what it sounds like, as early Europeans witnessed Native Americans consuming large amounts of a 'black drink' to induce vomiting as part of a purification ritual.  Steeped from toasted leaves and bark of this plant, this tea-like drink contained large amounts of the stimulants caffeine and theobromine, and is related to yerba mate, which is a traditional and still popular South American drink brewed from a different but related holly species.

Possumhaw, Ilex decidua

Possumhaw is also a large shrub or small tree with simple alternate leaves that are round at the tip and tapered at the base, but as suggested by its species name 'decidua', it is deciduous and loses its leaves in the winter.  That's when Possumhaw shines, however, spending most of the winter season with its’ bare branches adorned by bright red-orange berries.  Sometimes referred to as Winterberry, Deciduous Holly, or Swamp Holly, it is the larval food plant for the Dusky-blue Groundstreak butterfly.      



Grouping both of these hollies in your landscape with Carolina Buckthorn, Mexican Buckeye, Texas Redbud, and Spicebush creates a colorful and natural understory for an attractive woodland garden. Hollies are dioecious, meaning each plant is either male or female. The male plant provides the pollen, which is carried by bees up to a half-mile to a female plant, and used to pollinate it.  The berries on the female plant, while slightly toxic to humans, provide an important winter food source for small mammals and many different bird species, such as American robins, cedar waxwings, and northern mockingbirds.

Hollies have long been associated with the holiday season, with the roots of this tradition beginning in Europe and eventually brought to the New World. Over hundreds of years ago, druids considered holly to be a sacred plant, and associated it with the Roman God Saturn and the celebration of the winter solstice.  Plant some of our native hollies in your yard, and both you and the wildlife will enjoy a jolly holly season!  

The Simple Beauty of Sparrows

White-crowned Sparrow, Zonotrichia leucophrys

Coming from the Anglo-Saxon word ‘spearwa’ and literally meaning ‘flutterer’, sparrows often conjure up images of the ubiquitous and non-native House sparrow and the House finch, which isn’t a sparrow at all.  While most sparrows are generally small to medium brown birds with streaks, the differences between sparrows can best be determined by their relative size, head markings, and habitat.

White-throated Sparrow, Zonotrichia albicollis

All sparrows have conical bills that they use to shell seeds, a primary component of their diet year-round, but especially so in the winter months.  There is little difference between the males and the females in terms of appearance, but males are on average larger than females.  As a group, most sparrows are birds of grasslands, prairies, and marshes, and seem to prefer weedy fields and woodland edges in the winter.  Of the sparrow species that migrate, none travel further than the southern United States or northern Mexico.

Chipping Sparrow, Spizella passerina

One of our most common winter sparrows is the Chipping sparrow.  Small and slim, with a long notched tail, rusty cap, white stripe over the eye and a black line through the eye, this sparrow moves in loose flocks and frequently feeds in short grass and open woods.  While still fairly abundant, this sparrow is declining in numbers, mainly due to habitat destruction, and winters in the southern part of the United States.  When first identified in 1810 by an American ornithologist, it was nicknamed ‘the social sparrow’ for it was easily approached and associated with human habitation.

White-crowned Sparrow, Zonotrichia leucophrys 

A fairly large sparrow, the White-crowned sparrow is distinguished by its black and white striped head, unmarked gray breast, and dark pink bill.  It is found in large groups in thickets and weedy areas, foraging on the ground.  Discovered in 1772 by a German naturalist, this sparrow was originally named the ‘white-eyebrowed bunting’, for in the Old World, sparrows were usually called buntings. 

Found in a variety of grassy habitats, and often in small flocks, is the Savannah sparrow. Streaked on both their back and their breast, Savannah’s have pink legs, yellow above the eye, a thin white median crown stripe, and a short notched tail.  First described by a British ornithologist in 1790, it was called a ‘sandwich bunting’ due to the first specimens being collected from Sandwich Bay in the Aleutian Islands of Alaska.   

Lincoln's Sparrow, Melospiza lincolnii

Lincoln’s sparrow is a medium-sized bird with a rather short tail, broad gray stripe above the eye, buffy moustache stripe, and a buffy upper breast with crisp, blackish streaks.  Found in winter in brushy edges of ponds and other moist areas, this sparrow was named by John James Audubon in 1833 after his research companion, Thomas Lincoln, shot the first specimen in Labrador.       

Sparrows are gregarious and are often our most hardy winter visitors.  Adorned in various shades of brown, gray, black, and white, they reflect the subdued hues of a winter landscape.  Often dismissed as ‘little brown birds’ when seen with the naked eye, these birds invite closer inspection and are nature’s way of reminding us that subtle colors and patterns can be beautiful, too!   

Leafy Treasures

Fall is the time when the quiet, green palette of summer gives way to the crisp reds, vibrant oranges, and mellow yellows that paint the natural landscape.  During the growing seasons of spring and summer, our trees and shrubs use sunlight to convert water and carbon dioxide from the air into sugar.  Called photosynthesis, this process begins to wane in November in Central Texas, and the leaves on some plants begin to change color in preparation for winter’s rest.

Texas Red Oak, Quercus buckleyi

Pigments are natural substances formed by the cells of leaves which provide the basis for leaf color.  Most familiar is chlorophyll, which produces the color green, and is vitally important as it is required for photosynthesis.  Carotenoid, which produces the colors yellow, orange, and brown, is a common pigment in many fruits and vegetables, as are anthocyanins, which produce the color red.  Both chlorophyll and carotenoid are present at the same time in leaf cells, but the chlorophyll covers the carotenoid and hence the leaves appear green in the spring and summer.  Not all trees can make anthocyanins, however, and most are produced under certain conditions and only in the fall.

Mexican Buckeye, Ungnadia speciosa

As the days grow shorter, the decreasing amount of sunlight eventually causes trees to stop producing chlorophyll.  When this happens, the carotenoid in a leaf can finally show through, turning the leaves into a myriad of yellows, oranges, and browns.  Red, on the other hand, is an entirely different matter.  Affected by temperature and cloud cover, red fall colors can vary greatly from year to year.  A lively showing of reds depends upon warm, sunny autumn days and cool, but not cold autumn nights.  This type of weather pattern triggers the production of anthocyanins, which the tree produces as a form of protection.  Anthocyanins allow trees to recover any sugar or nutrients left in the leaves, moving them through the leaf veins and down into the branches and trunk, and its presence generates the red color before the leaves fall off.  Rainfall during the year can also affect fall color, with too much lowering the overall color intensity, and too little delaying the arrival of color.

Virginia Creeper, Parthenocissus quinquefolia

Fall leaf color can easily be used to help identify local tree and shrub species.  The most notable reds and oranges in our area are produced by Texas Red Oak and Flame-leaf Sumac.  Dotting the hillsides, roadsides, and upper reaches of wooded canyons, they contrast well with the surrounding greens of Ashe Junipers and Live Oaks.  Golden yellows are represented by Eastern Cottonwood and Escarpment Black Cherry, whose color transforms the low-lying areas near creeks and streams.   

Flameleaf Sumac, Rhus copallinum

While a tree’s trunk and branches can survive the colder winter temperatures, many leaves cannot.  Made up of cells filled with water and sap, these tissues are unable to live throughout the winter, and the tree must shed them to ensure its survival.  As the days grow shorter, the veins that carry sap to the rest of the tree eventually close.  A separation layer forms at the base of each leaf stem, and when complete, the leaf falls.  Some oak trees are the exception, with this layer never fully detaching and the dead leaves remain on the tree until new spring growth pushes them off to the ground.  Once on the ground, the leaves slowly decompose with the help of earthworms, beneficial bacteria, and fungi, creating the soil necessary for the continuation of the cycle of life. 

A Plethora of Parakeets

Monk Parakeet, Myiopsitta monachus

Established in Austin in the early 1970s from escaped caged birds, Monk Parakeets (Myiopsitta monachus) also known as Quaker Parrots, are native to the temperate and subtropical regions of Argentina and surrounding countries in South America.  ‘Monks’ are often heard before they are seen, as their call is a loud and throaty chap(-yee) or quak quaki quak-wi quarr, and their sometimes startling screeches sound like skveet!  They have grown in numbers by being able to survive our mild winters, and as such have now been included on the official list of accepted Texas bird species. 

A colorful bird with bright green upper parts, pale grey forehead and breast with darker scalloped edges, and very light green to yellow under parts, Monks also have an orange bill, stiff dark blue flight feathers, and a long tapered tail.  Technically a parrot, it is this tail that makes them a parakeet, which is a term for small to medium sized species of parrots that generally have long tail feathers.

Monks are the only parrot that builds a stick nest, either in a tall tree or man-made structure, rather than using an existing hole in a tree.  They often breed in colonies, building a single large nest that has separate entrance holes for each pair.  In the wild these colonies can become quite large, with communal nests reaching the size of a small automobile! Also unusual for a parrot, these birds occasionally have ‘helper individuals’, typically grown offspring, which assist in feeding the young.  Highly intelligent and social birds, Monks can live anywhere from 15 to 30 years, and like other species of parrots kept as pets, they routinely develop quite a large vocabulary.   

Monk Parakeet Nest

Monk Parakeets readily adapt to urban neighborhoods, as they are an open woodland species.  A recent informal survey found over 65 nests in Austin, mostly in cell phone towers, tall telephone poles, and sports facility light poles.  Even if the nests are cleared out, many colonies return to the same place to rebuild their nest.  While mainly constructed out of willow branches, these nests may include man-made items such as rope, carpet, newspaper, and scraps of cloth.  The Monks’ diet consists of berries, tree buds, and seeds, all of which can be plentiful in both the native and non-native the tree species common in the Austin area.

The exact number of wild Monks in our area is unknown, and evidence of harm by feral colonies of Monks is disputed.  While they can be agricultural pests by eating fruits, grains, and other crops, they can also benefit local economies through birdwatching-based ecotourism.  It is also important to remember that tens of millions of parrots have been removed from the wild worldwide, and have been traded in greater numbers and for far longer than any other group of wild animals.  Many parrot species are still threatened by this trade, as well as by habitat loss, predation by introduced species, and hunting for food or feathers.  As such, let’s respect their existence and enjoy our plethora of parakeets!

Mysterious Moths

Luna moth, Actias luna

While much more numerous but not as widely studied as their close cousin the butterfly, moths are a large and fascinating group of insects.  Making up about 80% of the insect order known as Lepidoptera, most moths are active mainly at night, strangely attracted to light, and while some never eat, many species can live much longer than most butterflies and can even hibernate over the winter.

Cecropia moth, Hyalophora cecropia, caterpillar

Like butterflies, the lifecycle of a moth is comprised of an egg, caterpillar (larvae), pupa, and adult. The length of this cycle and each of its phases varies with each species, with some species producing as many as 10 broods a year.  Many moths have hairy bodies to help maintain the internal body temperature necessary for flight, and heat up their flight muscles by vibrating their wings, since they don’t have the radiant energy of the sun to assist them.  Sphinx moths, whose wings beat 70 times per second, have a top speed of 50 kilometers per hour, and even more amazingly, many pupate underground! Moths range in size from the micros that have wingspans of 3-4 millimeters to the female Cecropia moth, with a record wingspan of over 130 millimeters, the largest insect in North America. 

Cecropia moth, Hyalophora cecropia, cocoon

Moths are positively phototactic, or automatically move toward a source of light.  While the exact reason for this is unknown, interesting theories abound.  Some moths are known to migrate short distances, and may use the night sky to navigate.  They may use the moon as a primary reference point and have the ability to calibrate their flight paths as the moon moves across the night sky.  This may help orient them, and can also explain the disorientation they seem to experience when they unexpectedly ‘catch’ or fly above a light source that they think is the moon. It’s also possible that moths look at light as an escape route mechanism, where flying up (toward the light) signifies safety, and flying down (toward the darkness) signifies danger.

Cecropia moth, Hyalophora cecropia

Once they find an appealing source of light (preferring white versus yellow wavelengths), moths seem entranced by it.  Like humans, moth’s eyes contain light sensors, but unlike humans their dark-adapting mechanism responds much more slowly than their light-adapting mechanism.  This could mean that they may not want to leave the light since the dark renders them blind for so long, and might explain why they can be attracted to the light over & over again.  Lastly, since moths are generally nocturnal creatures, they may respond to the light like they would the rising sun, and settle in for a good day’s sleep.      

With so many thousands of moth species, even the largest can be difficult to identify.  Clues can be gleaned from their profile or posture, vein patterns in their wings, and even the time of night that they are most active.  Moths have antennae that are either feather-like or hair-like, with the male’s antennae being larger than the female’s.  This is beneficial for detecting the pheromones (a chemical signal that triggers a natural response from a member of the same species) released by the females from as much as 8 kilometers away!  

Imperial moth, Eacles imperialis

Polyphemus moth, Antheraea polyphemus

Some of our most beautiful nighttime jewels include the Cecropia, Imperial, Luna, and Polyphemus moths.  These large  moths, all members of the Giant Silkworm (Saturniidae) family, hold our greatest fascination. Cecropia larvae grow to about 4 inches in length, and you can often hear them as they eat.  Imperial moths emerge in September/October awash in yellow & purple. The luminescent green Lunas, like all Saturniidae, are born without a mouth – they never eat or drink, as their main purpose is to reproduce.  And the Polyphemus is named for the Greek Cyclops due to the large purple eyespot on each hindwing.  So the next time you’re up at night, wander outside by a light and see if you can spot some of these lovely creatures!

Magical Monarch Migration

Monarch male, Danaus plexippus

Most of us are aware of the typical life cycle of a butterfly – first an egg is laid on a food plant, a caterpillar (or larvae) hatches from the egg, once the caterpillar eats enough it  turns into a chrysalis, and shortly after a beautiful adult butterfly emerges.  However, unlike other butterflies, migration plays a key role in the Monarch’s lifecycle, and it is a fantastic migration at that!

Monarch caterpillar

Monarch chrysalis

Unlike most other insects in temperate climates, Monarch butterflies cannot survive a long, cold winter.  Instead, they spend the winter in one of two main roosting spots – those west of the Rockies travel to small groves of trees along the California coast, and those east of the Rockies fly further south to the forests high in the Chihuahua Mountains of Mexico.  

Butterfly Milkweed, Asclepias tuberosa

Austin is on the very eastern edge of this central flyway to Mexico, and in October/November large numbers of Monarchs work their way through Central Texas.  These butterflies were actually born on milkweed plants in Canada earlier in the summer.  Even though they look like summer adults, they won’t mate or lay eggs until the following spring.  Instead, their small bodies prepare for a strenuous flight.  As they migrate southwards, the Monarchs stop to nectar, and actually gain weight in the form of fat to fuel their flight and last them throughout their winter roost.  These butterflies wake up about mid-morning, gathering nectar from flowers in full bloom, and fly until sunset, covering distances up to 400 miles in a single day.  Although this generation of butterflies has never ventured into Mexico in the past, somehow they still find their way. 

Once they reach their wintering grounds in Mexico, the Monarchs roost in huge clusters that virtually drip off the evergreen trees, and feed on the nectar of native plants.  If they survive the winter, they will begin the trip back to Canada in late March or early April.  Although the same butterflies that winter in Mexico don’t survive long enough to see Canada once more, the next three generations carry on the lifecycle as they migrate north.  Each first through third generation lives only six to eight weeks, and it is this fourth generation -- the great, great grandchildren -- that complete the return journey back into Mexico.

Driven by seasonal changes such as temperature and day length, the migration of the Monarch is unique in all the world.  They travel up to a total of 3,000 miles -- much farther than all other tropical butterflies and they are the only butterfly species to make such a long, two-way migration every year.  Amazingly, they fly in masses to the same winter roosts, often to the exact same trees, but unlike other migrating species (such as birds and whales), it is their children’s grandchildren that return south the following fall.  

Now that you know a little something about their magical migration, stop to admire these amazing beauties as you see them flutter by you this fall on their way to their winter home in Mexico! 

Sn-outbreak!

American Snout, Libytheana carinenta

The change from late summer into early fall can trigger some unusual natural events, and at this time of year in Central Texas, we can often see periodic population explosions of the American Snout butterfly.

Often mistaken for migrating Monarch butterflies, the American Snout (Libytheana carinenta) is a medium-sized butterfly with a brown upperside, wings orange at the base, and white spots near the tips of the forewings.  Their underside is a mottled grayish-brown pattern, much like a dried, dead leaf.  Snouts are named for their elongated mouthparts, and when they hang from the underside of a branch, which they most often do, their ‘snout’ resembles the stem or ‘petiole’ of a leaf and their folded wings appear to be the dead leaf itself.  It’s the perfect camouflage for defense against avian predators. 

In the caterpillar stage, snouts are dark green with yellow stripes along the top and sides of their body, with two small, black tubercles on the top of their thorax.  These caterpillars feed on all hackberry species, but they prefer spiny hackberry.  While Austin is at the northernmost boundary of this plant’s range, it is close enough that we get to experience a ‘sn-outbreak.’  After a good rain, spiny hackberry plants (also known as granjeno or desert hackberry) grow numerous new leaves.  In response, the snout butterfly lays its eggs on these new leaves, which provides the fuel for a significant number of its caterpillars.  In Texas, it only takes 12 days to go from egg to caterpillar to adult butterfly.

Spiny Hackberry, Celtis ehrenbergiana

The ecology behind this event is related to several factors.  First, the population of snouts is positively correlated to the intensity and duration of dry periods that immediately precede significant rains.  These droughts seem to greatly diminish parasites that can harm and kill snout larvae.  Second, adult snouts wait out these long, dry periods by remaining in ‘reproductive diapause’, a state of arrested development/reproduction and decreased metabolism in response to the adverse environmental conditions.  This condition reverses when the rains arrive and trigger the third factor, new growth on the spiny hackberry host plants.  Female snouts will only lay eggs on this prolific new growth, and coupled with the lack of parasites, this creates a population boom.

Most often, sn-outbreaks occur in South Texas and Mexico, where the spiny hackberry is plentiful.  However, one of the largest recorded snout emergences occurred in late September of 1921, when over the course of 18 days more than 6 billion southeasterly-bound snout butterflies flew over San Marcos to the Rio Grande River.  That’s an estimated 25 million per minute!  While not every year is quite that spectacular, keep your eyes open about two weeks after a rain, and you should see region-wide migrations of snout butterflies as they waft by in pretty impressive numbers.

Little Armored One

Spanish for ‘little armored one’, the armadillo is one of the most interesting mammals in North America.  All but one of the 20 different species of armadillo live in Latin America, but the Nine-banded Armadillo (Dasypus novemcinctus) makes its home as far north as Texas (except for the western Trans-Pecos), Oklahoma, and Louisiana.  In fact, this armadillo is the official state small mammal of Texas!

A cat-sized, insect–eating mammal, armadillos have bony plates that cover their back, head, legs, and tail, protecting them from predators. No other living mammal wears such a shell, but contrary to popular belief, the Nine-banded Armadillo cannot roll into a ball and encase itself with its shell.  Only the Three-banded Armadillo can accomplish this, by curling its head and back feet inward and contorting its shell as protection.  No amount of armor can protect them from the cold, however, and because of their low metabolic rate and lack of fur and body fat stores, cold weather can wipe out whole populations of these little creatures.

Armadillos have a pointy snout and small eyes, and are prolific diggers.  They dig for food and dig many burrows, mostly along creekbeds in Central Texas, and they do not survive in areas where the soil is too hard to dig.     Armadillos spend up to 16 hours a day digging, mainly active in the dawn and dusk hours, looking for beetles, ants, termites, and other insects. Their eyesight is quite poor, but they use their keen sense of smell to locate food, and utilize their long, sticky tongues to grasp berries, caterpillars, grubs, fungi, and sometimes even carrion.  

Armadillos are quite fond of water, visiting water holes and streams to drink, feed, and even take mud baths.  Their specific gravity is high, which means they normally ride low in the water when swimming.  For short water crossings, they often just walk underwater across the bottom, but for deeper and longer crossings they voluntarily ingest air to inflate themselves and increase their buoyancy by retaining the air in their digestive tract! 

Armadillos are thought to be a pair during the breeding season, sharing the same burrow.  Due to their bony shells and the underside location of their genitalia, copulation occurs with the female lying on her back.  While breeding occurs in July, the embryo remains in a dormant state until November. Always of the same sex, identical quadruplets develop from the single egg, and four young are born in a grass-lined burrow in March.

While the Nine-banded Armadillo is a unique mammal whose range is expanding northward, there is reason to be concerned about their conservation status in Texas.  Encroaching human civilization, overgrazing, and progressive climatic change may be keeping them on the move, and many mammalogists agree that armadillos are rare at best when compared to populations of a few years ago.  This decline also appears to be correlated with increasing populations of feral hogs, as well as the propensity for people to make trinkets from armadillo shells.  Perhaps our state motto should read ‘Don’t Mess with Texas Armadillos!’  

Meet the Jollyville Plateau Salamander

Jollyville Plateau Salamander, Eurycea tonkawae

Rare and under threat of decreasing population, the U.S. Fish & Wildlife Service has stated that the Jollyville Plateau Salamander (Eurycea tonkawae) warrants protection under the Endangered Species Act, due to its habitat undergoing rapid degradation as a result of urban and suburban sprawl.  Found only in the wet springs and caves of the Jollyville segment of the Edwards Plateau region of Travis and Williamson counties, the area this salamander inhabits is roughly bounded by the Colorado River, Mopac (Loop 1), Lake Travis, and U.S. 183.  More specifically, its known range is limited to only six stream drainages, all of which are facing water quality issues.    

Jollyville Plateau Salamander, Eurycea tonkawae

Very little is known about this small, localized amphibian.  Juvenile Jollyville Plateau Salamanders are less than 1.5 inches long, and the adults grow to up to 2 inches long.  They have large well-developed eyes, wide yellowish heads, feathery  external gills, blunt rounded snouts, dark greenish-brown bodies, and yellowish-orange tails. Most salamanders have feather-like external gills when they are young, but the Jollyville Plateau Salamander is neotenic, or keeps these external gills and remains aquatic for its entire adult life.  Since they never take a terrestrial form, these salamanders prefer cool, shallow, clean water containing loose gravel.  During drier periods, they remain in underground caves and water is provided for them by the infiltration of surface water through the soil into the aquifer which discharges from the springs as groundwater.  

Two other local salamanders have received protected status by the US Fish & Wildlife Service. These are the Barton Springs Salamander (Eurycea sosorum) and its lesser-known cousin the Austin Blind Salamander (Eurycea waterlooensis).  

Barton Springs Salamander, Eurycea sosorum

Austin Blind Salamander, Eurycea waterlooensis

Urbanization has been known to cause excess sediment to accumulate into the aquifer the salamanders inhabit and this sediment impairs their ability to avoid predators, locate food, and find mates.  In addition, development of upstream salamander habitat provides sources of various other pollutants such as chemical fertilizers, pesticides, and petroleum products.  During rainstorms, water runs off these urban areas and transports these pollutants into the salamander’s aquatic  habitat.  This degradation of water quality has been shown to be linked to deformities of the Jollyville salamander in some locations, as well as to declines in abundance of salamanders compared to areas that are undeveloped.

While the Balcones Canyonlands Preserve (BCP) provides some water quality benefits for the Jollyville Plateau Salamander through the preservation of drainages in the open space, several of the areas within its range have been or are being affected by water quality degradation occurring upstream and outside of the preserved tracts.  Work is being done to monitor and improve these areas within the BCP, but residents in neighborhoods surrounding the preserve can go a long way in helping to restore and maintain water quality by carefully disposing motor vehicle fluids, washing cars at a commercial car wash (where the water is captured & recycled), fertilizing wisely (organically), using compost, and planting native plants that have no need for chemical pesticides & herbicides.

And lastly, do what you can to help support the purchase and preservation of open space, unique natural features, and rare inhabitants of the hill country -- it Keeps Austin Beautiful!