Wednesday, March 25, 2015

The Buzz about Bees

There are over 1000 species of bees native to Texas, and this remarkable diversity is attributed to the high number of flowering plant species found in a multitude of habitats throughout the state.  Central Texas is home to at least 185 of these species, many of which inhabit our yards, gardens, and public green spaces.  Bees often get confused with other flying insects, mainly flies, wasps, and sometimes hawk moths.  Flies and wasps, in particular, have similar sizes, colors, and even stripes.  How can you begin to tell the difference?  

In general, bees have longer, thinner antennae, large eyes on the side of the head, four wings (although all four can be hard to see), at least partially fuzzy bodies, and can carry loads of moist pollen on their legs or abdomens.  Flies, on the other hand, have short, thick antennae, large eyes in front of the head, two wings, minute body hairs, and while pollen can stick to their bodies they don’t carry loads.  Finally, wasps have narrow bodies often with a pinched abdomen, very few body hairs, little to no patterns or designs in their exoskeleton, and like flies, don’t carry pollen loads.

Groups of bees that you will commonly see include metallic green bees, honey bees, bumble bees, and carpenter bees. Metallic green bees have an obvious metallic green exoskeleton, but care must be taken to use other methods of identification, as there are also metallic green flies and wasps.  Honey bees buzz as they fly from flower to flower, with a fuzzy thorax and striped abdomen, but while quite common and numerous, are a non-native bee imported from Europe.  

Our biggest native bees are the bumble bee and the carpenter bee.  Bumble bees have a robust body size and shape, mostly black with some yellow or white stripes.  Their entire body is fuzzy, and they fly around in a ‘bumbling’ pattern, making a low buzzing sound.  When landed, they fold their wings neatly over their abdomen.  Carpenter bees are mostly all black, some with a little gold or brown, and the top of their abdomen lacking hairs.  They are fast fliers, sometimes hovering like flies, and make a fairly loud buzz.  Upon landing, they keep their wings splayed apart.

Native bees could fill the important pollinator role currently held by the declining population of non-native European honey bees.  While there is still some debate as to the cause of this decline, there is no debate about the heavy reliance we have on bees pollinating many of our food crops.  Native bees offer an efficient alternative because they are resistant to the mites thought to be harming the honey bees, and because they do not live in collective hives but live singly in nest holes and tunnels, which are not at risk of being overcome by Africanized bees.  Further, native bees and their behavior have evolved so that their actions on a flower actually trigger pollination, so it is possible to find a native bee species that is evolutionally ‘tailored’ to assist a specific crop.  Now that’s something worth buzzing about!

Sunday, March 1, 2015

Spring Heralds

Texas Redbud, Cercis Canadensis var. texensis

Nature has a way of letting us know when spring has arrived in the hill country of central Texas.  In addition to increasing temperatures, the awakening of birds, butterflies, and native plants are among the harbingers that mark the arrival of the season.

More than half of the birds recorded in Texas are migrants.  Returning north in the spring to exploit the more productive temperate regions, they come in search of abundant food supplies, longer daylight hours, and less competition for nesting space. Texans have the advantage of being situated in the path of two flyways or principal routes used by North American birds – the Mississippi Flyway and the Central Flyway – and of the 338 species of North American species listed as Neotropical migrants, 333 are documented for Texas.

Chuck-will's-widows, Caprimulgus carolinensis, lay their eggs on the ground in the spring

Listen for the song of the Chuck-will’s-widow (Caprimulgus carolinensis), which sounds just like its name, rising up from the canyons in the twilight and pre-dawn hours.  Delight in the acrobatic flight of a Scissor-tailed Flycatcher (Tyrannus forficatus), a pearl gray and white bird with salmon-pink underwings and very long outer tail feathers, whose return coincides with the leafing out of the native Honey Mesquite (Prosopis glandulosa var. glandulosa) trees. Marvel at the nest-building skills of the Cliff Swallows (Petrochelidon pyrrhonota), who zoom down to creek beds gathering mud to build colonies of gourd-shaped nests under our bridges and overpasses.  And watch for the Western Kingbird (Tyrannus verticalis), a gray bird with a pale breast and yellow belly, whose raucous calls are heard in between bouts of insect-chasing from perches high in our neighborhood trees.

Scissor-tailed Flycatcher, Tyrannus forficatus

The sweet scents of early-blooming native plants catch our attention and the attention of many pollinating insects.  Some of the most fragrant include the Texas Mountain Laurel (Sophora secundiflora), whose glossy, evergreen leaves form the perfect backdrop for huge clusters of deep purple to whitish flowers, up to ten inches long, that smell like grape Kool-Aid.  Or the less common Mexican Plum (Prunus mexicana), a beautiful small tree identified by its numerous and intensely fragrant white blossoms, which like the pink blossoms of the Mexican Buckeye (Ungnadia speciosa) and the Texas Redbud (Cercis Canadensis var. texensis) and the yellow blossoms of the Elbowbush (Forestiera pubescens), appear on the tree before the leaves begin to emerge.  

Mexican Plum, Prunus mexicana
Elbowbush, Forestiera pubescens

Many of these native plants provide nectar for several species of bees, and are nectar and/or larval food sources for spectacular butterflies such as the Giant Swallowtail (Papilio cresphontes), Two-tailed Swallowtail (Papilio multicaudata), Great Purple Hairstreak (Atlides halesus), Juniper Hairstreak (Callophrys gryneus), Long-tailed Skipper (Urbanus proteus), and Henry’s Elfin (Callophrys henrici).

Henry's Elfin, Callophrys henrici
Juniper Hairstreak, Callophrys gryneus

Wildflowers will soon begin to grace our fields and roadsides, starting with the famous Texas Bluebonnet (Lupinus texensis), intermingled with Indian Paintbrush (Castilleja indivisa), pink Evening Primrose (Oenothera speciosa), Winecup (Callirhoe involucrata), and Indian Blanket or Firewheel (Gaillardia pulchella), to name a few.   These swaths of multi-colored gems not only delight the eye and provide the perfect setting for those upcoming Easter family photos, but they are a key element of the hill country ecosystem, and should be protected and propagated for the visual enjoyment and habitat value they provide all living things.          

Prairie Paintbrush, Castilleja purpurea var lindheimeri

As the weather warms, take the time to go outside and discover for yourself the distinctive essence of a central Texas spring.  As Lyndon Baines Johnson, one of our more famous Texans said, “The beauty of our land is a natural resource.  Its preservation is linked to the inner prosperity of the human spirit.”  Celebrate it!

Sunday, February 1, 2015

Winter Visitors

A congregation of Cedar Waxwings

Like many people from northern climates, there are several bird species that arrive in central Texas to spend the winter!  Three of the most notable are the American robin, the Cedar waxing, and the American kestrel.

American Robin, Turdus migratorius

The largest of our thrushes, the well-known American robin is gray-brown above, with a brick-red breast, white belly, and black-streaked white throat.  Like all thrushes, it is one of our best singers (“cheerily cheer-up cheerio!”), and was named by homesick colonists for the robin that occurs commonly across Europe.  The two are only distantly related, but both have red breasts.  Robins withdraw from the northern portion of their range in winter and migrate southward to seek more abundant food supplies.  They winter throughout Texas, but remain to breed primarily in the northern and eastern portions of the state and locally in the mountains of the west.  On their southern wintering grounds here in central Texas, they congregate in huge flocks, feeding together mostly on berries, and roosting en masse in trees at night.  Earthworms are an important food source during their breeding season, and because they forage for worms largely on suburban lawns, they are vulnerable to pesticide poisoning and can be an important indicator of chemical pollution.

Cedar Waxwing, Bombycilla cedrorum

Gray-brown overall, with a crest on top of the head, black mask edged in white, and yellow tips on its tail feathers, the Cedar waxwing is a beautiful medium-sized songbird.  Gregarious and often flying in flocks, its calls sound like very high-pitched “bzeee” notes.  The waxwing gets its name from the waxy red appendages found in variable numbers on the tips of the secondary wing feathers of most birds.  Waxwings with orange instead of yellow tail tips began appearing in the US in the 1960s as a result of a red pigment picked up by the birds from eating the berries of an introduced (non-native) species of honeysuckle.  One of the few temperate dwelling birds that are “frugivorous” or specializing in eating fruit, waxwings swallow berries whole.  They can survive on fruit alone for months, and unlike many birds that regurgitate seeds from the fruit they eat, waxwings ingest and then defecate fruit seeds.  They are also vulnerable to alcohol intoxication and even death after eating fermented fruit!     

American Kestrel, Falco sparverius

A robin-sized falcon, the American kestrel is a gorgeous bird of prey with a sharp, hooked bill and talon-tipped feet ideal for hunting.  Sometimes called a “sparrow hawk”, the male kestrel is a rust-colored bird with slate blue wings and an unbarred tail while the female, the larger of the two, sports a barred tail and lacks the slate blue on the wings.  Both possess a white face with two black streaks.  Typically, it is the larger female kestrel that arrives on its wintering grounds ahead of the male, which allows her to select preferred habitats, so when the smaller males arrive they must take secondary locations. They utilize open fields and other grassy areas with perches from where they can watch for prey such as flying insects, bats, mice, small birds and reptiles.  They can hover in mid-air while searching for prey and “kite” against the wind, flying at an appropriate speed facing the wind so they can stay in place.

As you enjoy a brisk winter walk in the neighborhood and surrounding areas, keep an eye out for these common but attractive “winter Texans”!  

Friday, December 5, 2014

Merry Mistletoe

From the earliest times mistletoe has been considered one of the most magical, mysterious, and sacred plants found in European folklore.  Originally used to bestow life and fertility, as a protection from poison, and as an aphrodisiac, in medieval times branches of mistletoe were hung from the ceiling to ward off evil spirits. With the process of immigration and settlement of North America, traditions associated with the European plant were transferred to the New World and evolved into a folklore all its own.

In Central Texas, two species of mistletoe are native, the Christmas Mistletoe (Phoradendron tomentosum) and Oak Mistletoe (Phoradendron leucarpum).  The genus comes from the Greek ‘phor’ which means thief and ‘dendron’ which means tree, as both species are semiparasites that steal water and nutrients from their host trees.  Christmas mistletoe has small, elliptical evergreen leaves and smooth green stems covered by short hairs, with tiny green flowers on the male plant and shiny white berries on the female plant. It is widely used in the United States as a Christmas decoration, and is especially common growing on Sugar Hackberry, Cedar Elm, and Honey Mesquite trees in Texas, Louisiana, and Oklahoma.

Native north to New York State, south to Florida, and west to New Mexico, Oak Mistletoe is another common mistletoe hung at Christmastime.  It is a larval host plant for the Great Purple Hairstreak butterfly, and while similar in appearance to Christmas Mistletoe, its berries are covered with a sticky substance poisonous to humans but relished by winter resident birds such as Cedar Waxwings, Eastern Bluebirds, and American Robins.  These birds eat the berries and spread the seeds through their droppings and by wiping their beaks on tree branches, both of which may cause a new plant to take hold and become established.

Great Purple Hairstreak

While ancient folklore has attributed a wide range of mystical abilities to mistletoe, none is more fascinating than the myth of Frigga, the Norse Mother Goddess worshiped by pre-Christian people of northern Europe, and how mistletoe became her sacred plant.  She was believed to be the mother of Balder, the God of the Summer Sun, who had a dream of death.  Alarmed by this dream, Frigga went to all the elements, plants, and animals to seek a promise that no harm would come to her son.  Balder was thought to be safe from harm by anything on or under the Earth.  

But Balder’s enemy, Loki, was the God of Evil, and he knew of the one plant that Frigga overlooked.  It was the lowly mistletoe, which grew neither on nor under the Earth itself, but on the branches of oaks and other trees.  Loki made an arrow tip with the mistletoe, and gave it to the Hoder, the blind God of Winter, who used it to strike Balder dead.  The sky paled and everything wept for the Sun God, who was restored by Frigga after working with the elements for three days. The tears she shed for her son were said to be the pearly white berries of the mistletoe, and in her joy at his resurrection she kissed everyone who passed beneath the tree on which it grew.  

Thus began the custom that whomever should stand beneath the humble mistletoe will come to no harm, but receive only a kiss as a token of love.  Merry mistletoe to you and yours!

Thursday, November 27, 2014

Shadow Tails

Fox Squirrel, Sciurus niger

The word ‘squirrel’ comes from the Greek ‘sciourus’, meaning ‘shadow tail’, and refers to the bushy appendage possessed by most all squirrel species.  They are members of the rodent family, and Texas is home to 10 species of squirrels with 4 of them common in the Austin area.

Along with their bushy tails, squirrels are generally slender animals with large eyes and soft fur. Their front limbs are shorter than their hind limbs, with 4 or 5 toes on each foot.  Their front feet include a usually underdeveloped thumb, and all toes have sharp claws for climbing trees and quickly clamoring over uneven terrain. Squirrels are strongly vegetarian, and feed mostly on a wide variety of seeds, nuts, fruits, buds, bark, and leaves.  Their vision is sharp and they have ‘vibrissae’ or specialized hairs on their head and limbs, which afford them an excellent sense of touch.   

The most common tree squirrels in Central Texas are the Eastern Fox Squirrel (Sciurus niger) and the Eastern Gray Squirrel (Sciurus carolinensis). A large squirrel with rusty or reddish underparts and grayish or brownish upperparts, the Fox Squirrel prefers open woodlands of mixed trees and riparian areas along rivers and streams, and makes its dens in hollow trees or nests made of leaves.  Their diet is largely made up of acorns which are buried in winter and relocated through their keen sense of smell. Mating occurs in January/February, and again in May/June, with offspring born in March and July.  

The Gray Squirrel is a medium-sized squirrel with grayish upperparts with white-tipped hairs, white underparts, and a white spot at the base of its ears in winter.  Gray Squirrels live in dense live oak stands and bottomland areas, with the Austin area in the westernmost part of their range.  There are usually two openings to their nests, which are otherwise similar to the Fox Squirrel, as is their diet and breeding cycle.  Destruction of bottomland habitat from logging, overgrazing by livestock, and development are the main reasons why gray squirrels are only locally common, and declining in many areas.      

Rock Squirrel, Spermophilus variegatus

Our most frequently seen ground squirrels include the Rock Squirrel (Spermophilus variegatus) and the Mexican Ground Squirrel (Spermophilus mexicanus).  A rather large, stout squirrel with a blackish head and upper back and a mottled grayish-brown rump and tail, the Rock Squirrel is nearly always found in rocky canyons, cliffs, and rock piles, where they make their dens.  While they can climb trees, they prefer to be ground dwellers, where they forage for acorns, nuts, insects, and berries.  In Central Texas, these squirrels hibernate beginning in November, and emerge in late February or March to begin breeding.

Mexican Ground Squirrel, Spermophilus mexicanus

The western edge of Austin is the easternmost range for the Mexican Ground Squirrel, a rather small squirrel with about nine rows of squarish white spots on its back and a moderately bushy tail. They prefer brushy or grassy areas, including mowed lawns and overgrazed pastures and live in burrows dug into the soil.  They eat chiefly green vegetation and insects, but are one of the few squirrel species that will eat meat.  Breeding begins in late March or early April, with a brood chamber built into a side tunnel in the deepest part of their burrow. 

Anyone who has seen a squirrel running along a tree limb or across an open road with its bushy tail undulating and waving behind it, or spotted a squirrel sitting with its tail curled over its back while it eats or surveys its surroundings, can appreciate why their name means shadow tail!

Thursday, October 30, 2014

Blooming Mist

All members of the Aster family, the Eupatorium genus of flowering plants are characterized by their medium-tall to tall stems and triangular, toothed leaves, topped with a cluster of small composite flowers.   They grab our attention in the fall as their blooms are prolific, like small clouds of mist, on which late-season butterflies, bees, and moths are eager to gather.  It’s easy to see why they are commonly called mistflowers, but they are also called bonesets, thoroughworts, and snakeroots.

To add to the mystery, the classification of this tribe of plants is the subject of ongoing research, and many species that were once grouped under Eupatorium have recently been moved to other plant families, or genera.  Conoclinium, the mistflowers, is a genus that includes only 4 species native to North America, and having blue to purple flowers.  Ageratina, or snakeroots, has over 250 species, and they grow mainly in warmer regions.

Commonly named for medicinal uses, various members of this plant family have been used to treat fevers and other health ailments.  Boneset alludes to the use of the plant to stimulate calcium production to speed the healing of broken bones, although the name may have also come from its use to treat dengue fever, also called breakbone fever due to the pain it inflicted.  Thoroughwort is named for its ‘perfoliate’ leaves, or the way the stem appears to pierce (or go through) the leaf.

Blue mist flower, Conoclinium coelestinum

In the hill country, Blue mistflower (Conoclinium coelestinum) is also called wild ageratum or blue boneset. Forming fairly large, bushy clumps 1-4 ft tall on moist soils near streams and in low meadows, its opposite leaves are triangular, wrinkled, somewhat thick, and smell a bit like tomato plants when crushed.  Preferring sun to partial shade, its lavender to sky-blue clusters of flowers bloom from October to December, subject to the first frost.

Gregg’s mistflower, Conoclinium greggii

Named after the 19th century explorer and naturalist Josiah Gregg, Gregg’s mistflower (Conoclinium greggii) is native to west Texas but spreading eastward to the Edwards Plateau.  Also called palmleaf thoroughwort or purple palmleaf mistflower, this 1.5 to 2 ft tall perennial has puffy, purple-blue flower heads from March through November.  Often attracting impressive numbers of nectaring Queen butterflies in the fall, this plant is found along seasonally flooded streambeds and has a lighter green, more delicate foliage.

Shrubby boneset, Ageratina havanensis

Also called Havana snakeroot, white mistflower, and white shrub mistflower, Shrubby boneset (Ageratina havanensis) is a rounded, open woody shrub, 2-5 ft tall, and multi-branched.  Its leaves are triangular with toothed edges, relatively thin, and about 2 inches long.  Blooming in October and November, the profuse flowers are fuzzy, pinkish-white, and very fragrant. Deciduous and drought-tolerant, Shrubby boneset is found on rocky hillsides and bluffs in the southern half of hill country.  Butterflies, moths, and hummingbirds, love the upright, fuzzy flower heads, and this plant is the larval host plant for the difficult to identify Rawson’s metalmark. 

Late boneset, Eupatorium serotinum

Late boneset (Eupatorium serotinum), also called late-flowering thoroughwort or white boneset, is an open, woody shrub up to 3 ft tall, with leaves up to 5 inches long, opposite and coarsely toothed.  Blooming in October and November, it likes partial shade, and is found in the eastern to central portion of the state, usually in meadows, woodland edges, near ponds or moist stream banks.   

Regardless of their classification, these native fall bloomers are a haven for wildlife.  Seek them out when hiking along your favorite trail – their intricate, fuzzy blooms beckon you to explore them up close!

Monday, October 13, 2014

Prophets and Phantoms

Mantid species

While most think of fall as a time when nature is waning and lifecycles are nearing their end, some things are just beginning.  This is the time of year when some of our most mysterious-looking insects, the praying mantids and the walking sticks, lay their eggs in anticipation of the next generation to hatch in the spring.   

The scientific order for praying mantis (Mantodea) comes from the Greek meaning 'prophet'  so named for its typical prayer-like stance.  This term is often misspelled as ‘preying mantis’ since mantids are a predatory species.  Several species exist in Texas, all of the genus Stagmomantis. Adult mantids are green to grayish brown, may reach 2 to 3 inches in length, and have well developed wings.  They have two grasping, spiked forelegs in which prey are caught and held securely while eaten. Their hunting relies greatly on their vision, and they can rotate their head nearly 300 degrees.  Consuming mostly insects, mantids are ambush predators that wait perfectly still until prey ambles near, and then strike with surprising quickness and agility. 

Praying mantids are experts at concealment, using their protective coloration to blend in with or mimic foliage, better snare their victims, and avoid predation themselves.  They do show a rocking behavior in which the insect makes a rhythmic, repetitive, side-to-side movement.  It is thought that this behavior may help them resemble vegetation blowing in the wind, but also allows them to discriminate objects from their background by their relative movement.  As generally sedentary insects, this behavior most likely replaces flying or running as a way to determine relative objects in their visual field.  When threatened they will stand tall, spread their forelegs, and fan their wings out wide to appear larger, and if further provoked will strike with their forelegs and attempt to pinch or bite.             

In the fall after mating, female mantids lay between 10 and 400 eggs, depending on the species. The eggs are typically laid in a frothy mass on the underside of a leaf or on a twig, which hardens to a tan or gray foam-like material called an ‘ootheca.’  If this egg case survives the winter, the nymphs emerge in the spring with voracious appetites, often devouring each other in their race to become mature adults.


Members of the Phasmatodea order of insects are commonly known as walking sticks, stick-bugs, ghost insects, leaf insects, and stick insects.  This scientific name comes from the Greek ‘phasma’ which means 'apparition' or 'phantom', and refers to many species closely resembling sticks and sometimes leaves.  At 16 species, Texas walking stick diversity is second only to California.  In fact, one species in Texas is the Giant Walkingstick (Megaphasma dentricus), which is the longest insect in the United States and grows to almost 7 inches!

Walking stick species
Our most frequently seen phasmid is the Common or Northern Walking Stick (Diapheromera femorata).  Adult males can be 3 inches long and are mostly brown, while females are larger at 4 inches and more of a greenish-brown.  Their long, thread-like antennae are about to-thirds the size of their body.  As part of their natural camouflage, their bodies are often further modified to include ridges resembling leaf veins and bark or bud-like tubercles, making them very difficult to spot. They are wingless, molt several times and may eat their shed skin as they grow to adult size.  

Phasmids feed mostly on the leaves of trees and shrubs, and often exhibit the same rhythmic movement as mantids, presumably to blend in to their surroundings and as  protection from predators.  At this time of year, the females lay anywhere from 100 to 1200 eggs individually, sticking them to vegetation or simply depositing them on the ground.   These eggs resemble tiny plant seeds and remain dormant until spring.  

While no doubt strange-looking and mysterious, mantids and phasmids are harmless to humans and beneficial components to keeping balance in our natural landscape.