Breaking Slumber

 

Many small creatures awaken in Spring

In the winter months in central Texas, most cold-blooded reptiles and amphibians exhibit a form of hibernation called brumation. Triggered by shorter days and lower temperatures, this state can last for days or weeks, depending on the species. Brumation differs from true hibernation in that these animals remain semi-conscious and occasionally wake up to drink but not eat. During this period, body temperature, heart rate, and respiratory rates are greatly reduced.  This state of dormancy occurs with several common amphibian species, including the Rio Grande Leopard Frog (Lithobates berlandieri), Gulf Coast Toad (Incilius nebulifer), and Green Tree Frog (Hyla cinerea).

Rio Grande Leopard Frogs are medium-sized native frogs, to 4.5 inches, greenish-brown in color with a yellowish ridge along each side of the back. They have large dark spots on the back and sides, and a wide, light-colored jaw stripe that is poorly defined and fades in maturity. Their call is described as a short, low-pitched guttural rattle, either given singly or in rapidly repeated sequences. These frogs spend the winter months resting at the bottom of ponds, lakes, or other bodies of slow-moving water, but can become active during warmer, wet periods. Since they are semi-aquatic, they can also tolerate cold conditions by burrowing into mud or soil. They tend to enter brumation just before freezing weather, and often hide in deeper water to temporarily escape extreme temperatures.

Rio Grande Leopard Frog

The Gulf Coast Toad is a native, broad-headed, mostly terrestrial toad, to 5 inches, with prominent cranial crests that form a depression on top of the skull. Their background color is brownish-yellow to brownish-gray, with broad dark lateral stripes bordered by a light stripe, as well as a light central stripe, and they are covered in numerous small whitish to orange spots. Their vocal sac becomes large and rounded when calling, which sounds like a short, flat trill repeated several times. These toads are usually dormant from December to February, hunkering down in self-dug holes, abandoned animal burrows, under logs, or in leaf litter to protect themselves when the temperature dips below freezing. While they become active as the temperatures rise in early spring, they may also burrow to survive hot, dry conditions in the summer months, and this unique behavior is called aestivation.

Gulf Coast Toad

Green Tree Frogs are smaller, native arboreal frogs, to 2.5 inches, with smooth skin, a slender, flat body, and long slender legs with large toe pads on each foot. In warmer conditions, when the frog is active, they are typically a bright green color, but they can change to a dull color during periods of cool weather or to blend in with their surroundings. They also have a long white stripe on either side of the body. Their call sounds vaguely like a honking duck and is repeated 30 to 60 times a minute. These frogs brumate in the winter months, often hiding under deep leaf litter, in tree cavities, in potted plants, or even in the corners of garages and sheds. During this time of inactivity, they slow their metabolism and sometimes survive partial freezing by producing natural antifreeze compounds called glycerol that protect their cells. They also typically choose sheltered damp spots to avoid freezing completely, and may wake on warmer, sunny winter days to move about.

Green Tree Frog

As they days get longer and temperatures begin to rise, once again we will be treated to the sights and sounds of these marvelous amphibians, as they break their winter slumber!

Butterflies in Winter

Early blooming plants like Elbowbush attract butterflies  

While butterflies are most noticeable in spring, summer, and fall, seeing them in the middle of winter is often surprising.  Most spend the winter in the egg, larva, or chrysalis stage of development, concealed in leaf litter or in other forms of vegetation, but some overwinter as adults.  

Most of the adult butterflies observed in the winter belong to the Brushfoots, a highly variable group of primarily mid-sized butterflies, some with irregular wing shapes, and many that fly with distinctively alternating flaps and glides.  In our area, the adult butterflies in this group most often seen in the winter, usually on a particularly warm sunny day, include the Red Admiral (Vanessa atalanta), Question Mark (Polygonia interrogationis), and Painted Lady (Vanessa cardui).

The Red Admiral is a common butterfly, not to be confused with any other species.  Dark above with fiery orange-red slashes and white spots on the outer part of the forewing, their flight is fast and erratic, darting out at anything crossing their path. Their larval host plants include nettles and pellitories. 

Red Admiral

Question Marks are also quite common, and their orange forewings and hindwings are sprinkled with dark brown dashes and dots, especially in the winter form (oddly, in summer their hindwings are mostly black). Their wings have irregular edges with a somewhat hooked forewing tip and a short tail on the hindwing. But their most distinctive feature is the silvery comma and adjacent dot forming a question mark in the center of the hindwing’s underside. Their larval host plants include nettles, hackberries, and elms.

Question Mark

The Painted Lady is one of the most familiar butterflies in all of the US. They are orange and black with a black patch and white spots on the forewing tips and a row of small black spots on the hindwing. On the hindwing’s underside, they have a row of four small eyespots which help distinguish them from American Lady butterflies. Their larval host plants include mainly thistles and mallows.

Painted Lady

But how do these adult butterflies survive the cold? First, they begin to enter a period of suspended development in the fall, called diapause, which causes their metabolic processes to slow down considerably. Second, their bodies produce chemicals that act as natural antifreeze, preventing their body fluids from freezing. And third, they find protected locations to shelter from the cold, such as in tree hollows, under loose bark or leaf litter, in cracks between rocks, or among dense, dry brush. 

Those butterflies that overwinter in the egg, larval or pupal development stage have hidden homes in the colder months. Some are lying in leaf litter on the ground, while others are slumbering in silk shelters on spent stems and along grass blades. While it can be difficult to spot these hidden homes, be mindful that these vulnerable creatures are asleep in our yards and green spaces, and try to hold off on removing all leaf litter and performing cut back until the beginning of spring. 

Winter Warblers

 

Warblers in winter?  Who knew!

New World warblers, often called wood warblers, are a group of birds found predominately in the Americas. They are relatively small birds with thin, pointy bills, and are famous for their diverse and high-pitched songs. Many warbler species are migratory, breeding in North America and traveling to their Central and South American overwintering grounds each fall.  But there is a certain warbler species that stops short of traveling so far south, spending its winters in the central and southeastern portions of the United States, including most of Texas. That species is the Yellow-rumped Warbler (Setophaga coronata).

While the Yellow-rumped males are most colorful during the spring and summer breeding season when they sport a dazzling mix of bright yellow, charcoal gray, black, and bold white, in winter their plumage coloring subdues, but still exhibits their trademark bright yellow rump with some yellow on the sides. Females are always duller, and may show some streaky brown, but like the males they also have a yellow rump, which is why these birds are sometimes affectionately called ‘butterbutts’.

'Myrtle' form of the Yellow-rumped Warbler

The Yellow-rumped Warbler has two distinctive subspecies that used to be considered separate species: the ‘Myrtle’ Warbler of the eastern U.S. and Canada, and ‘Audubon’s’ Warbler of the mountainous west.  The Myrtle form has a white throat and is more common here, and the Audubon’s has a yellow throat and can be found in west Texas.

'Audubon's' form of the Yellow-rumped Warbler

Like most warbler species, Yellow-rumps are active birds, even in winter, foraging for insects in open woods and shrubby habitats.  This time of year, they supplement their insectivore diet with native berries from Ashe Junipers, Poison Ivy, Greenbrier, Mustang Grape, Winter Grape, Virginia Creeper, and Roughleaf Dogwood.  However, they prefer the fruits of Wax Myrtle and Bayberry, as their digestive systems are uniquely suited to process their waxy berries, thanks to specialized microbes in their gut.  This ability allows them to remain farther north than other warbler species during the colder months. 

Winter plumage of Yellow-rumped Warbler

In winter, Yellow-rumps will join flocks and even come to feeders where they’ll eat sunflower seeds, raisins, suet, or peanut butter.  Flocks can be mixed species of other winter birds or even large groups consisting entirely of Yellow-rumped Warblers. But if another bird gets too close, they respond to the infraction by holding their body horizontally and raising their fanned tail to form a right angle to their body, indicating that they want the other bird to give them some space.

The Yellow-rumped Warbler’s flight is agile and swift, and they often call as they fly and change direction. Their sharp chips are quite distinctive, and they even call while foraging. Learn to recognize their sound and you will then be able to locate and enjoy these delightful winter warblers!

Autumn Ambrosia

 

Fall blooming plants are a boon to pollinators.

While little else is flowering in our yards and gardens as temperatures cool and the drought wears on, some wild native plants are still blooming and helping to support a myriad of insects. Some of the most important species of these fall blooming plants include Frostweed (Verbesina virginica), Poverty Weed (Baccharis neglecta), and Shrubby Boneset (Ageratina havanensis).

Blooming Frostweed.

Much of the year, Frostweed goes unnoticed while it grows 5 to 8 feet tall and leafy, the top of each stalk crowned by a cluster of small white flowers.  Its stalks are oddly square-like, with fleshing green flanges. Frostweed begins to bloom in the August heat, and continues until first frost, well into the fall.  These flowers provide late-season nectar for many insects, including bees, beetles, flies, wasps, and even migrating hummingbirds and Monarch butterflies. It is also a host plant for Silvery Checkerspot and Bordered Patch butterflies.

A Monarch nectaring on Frostweed.

Frostweed seems to be better known for its ability to produce frost flowers, a process called crystallofolia. With the first frost, the water contained in each Frostweed plant stem expands, causing the stems to crack.  Via capillary action, more water is drawn through the cracks, freezes when it hits the cold air, and forms long curls of ice like petals of a flower, ribbons, or other delicate, abstract sculptures.  Most often, they consist of longitudinal bands of fine ice threads at right angles to the stem.  These delicate frost flowers are fleeting in nature, and can only be found in early morning, as the rising temperature quickly melts them away.  

Frost Flowers.

Poverty Weed, also called Roosevelt or New Deal Weed and False Willow, is a weedy, tall shrub that often grows in disturbed ground or fields out of cultivation. It has ascending branches, very narrow partly evergreen leaves, and in October and November the female plants produce inconspicuous greenish-white flowers in large clusters that together resemble silky plumes. It is precisely these flowers that provide much needed nectar for migrating Monarchs and numerous other insects every fall.  

Blooming Poverty Weed.

While Poverty Weed is native, it can be invasive but is extremely drought tolerant.  In fact, several of its common names come from the fact that it was planted in fields as a fast and easy way to rejuvenate the severely damaged soil after the Dust Bowl and Depression period of the 1930s during the Franklin D. Roosevelt presidency.

A Tarantula Hawk nectaring on Poverty Weed. 

Found on the rocky hillsides and limestone bluffs at woodland edges in the southern half of the Hill Country, Shrubby Boneset is a many-branched, rounded shrub with opposite, triangular, coarsely toothed leaves.  Also called White Mistflower and Havana Snakeroot, in the fall it produces prolific, long-lasting, fragrant, pinkish-white blooms occurring in fuzzy terminal clusters. These flowers attract an amazing number of pollinators, including butterflies, moths, bees, hummingbirds, and beetles. 

Blooming Shrubby Boneset.

Shrubby Boneset is also a host plant for Rawson’s Metalmark butterfly, and in early winter the plant’s seed clusters provide much needed food for seed-eating birds such as the Lesser Goldfinch. Long ago, the common name of ‘boneset’ was applied to various plant species that were used as treatments for broken bones and dengue fever, also known as breakbone fever.

A Common Mestra nectaring on Shrubby Boneset.

Be inspired to create your own white-flowered buffet of autumn ambrosia by planting these natives in a sunny corner of your backyard. You’ll be giving a boost to many beneficial insect pollinators, and you’ll likely help a few Monarchs along the way!

Pollen Positives

 

Giant Ragweed, the bane of many fall allergy sufferers.

While fall is welcomed for the relief it gives from the long, hot summer, it is also a season when allergies run rampant.  These allergies are caused by various pollens, and those who suffer might wonder if there are any positives to pollen at all.  The answer is yes!

The definition of pollen is a fine, powdery substance consisting of microscopic grains discharged from the male part of a plant.  It is necessary for reproduction, and is transported by the wind, insects, or other animals. The grains from each species have a distinct symmetrical shape, surface pattern, and overall structure, and are easily recognizable under a microscope.  Due to their high resistance to decay, pollens have been commonly found in both recent and ancient geologic sediments.  In fact, the study of plant pollen in both living and fossil form is known as palynology. Since pollen is produced in large quantities at certain times of the year, it is often a significant component of the Earth’s atmosphere.

Scanning Electron Microscope (SEM) image of pollen grains, showing their unique shapes. (Credit: Dartmouth College, Electron Microscope Facility)

Many flowering plants produce all-important nectar, but it is pollen that is the most highly nutritious offering, consumed by virtually all bees, as well as beetles, flies, butterflies, birds, and mammals. Most plants produce pollen in excess, to ensure that at least some of it is used for pollination.  Pollination occurs when pollen is transferred from the male anther (fertilizing organ) of a flower to the female stigma (receptive tip of the pistil) of the same flower or one nearby.  This is often accomplished with the help of the animal pollinators listed above. This time of year, the plants that produce the most pollen are Giant Ragweed (Ambrosia trifida) and Cedar Elm (Ulmus crassifolia).

Like all ragweed species, Giant Ragweed is in the genus Ambrosia, because it was long ago believed that it would grant immortality or eternal youth to those who consumed it. Giant Ragweed can grow from 6 to 20 feet tall, especially in roadsides and disturbed areas. Flowering occurs from June to October, with inflorescences forming a spike or spikes made up of many tiny flowers at the top of the plant. These flowers are wind-pollinated, releasing copious amounts of pollen in the fall, eventually developing into small burs tipped with several miniscule spines. 

Giant Ragweed flowers.

Giant Ragweed seeds (burs).

Unlike many other tree species, Cedar Elms flower from late summer to early fall, usually July through September. Their flowers are tiny, pale reddish-purple, lacking petals, and they appear in clusters at the leaf axils. They are wind-pollinated, and after pollination they develop into flat, oval, winged seeds called samaras, which are an important food source for deer, squirrels, and birds. This fall flowering and fruiting is a distinctive feature of Cedar Elms and helps to distinguish them from other native elm species.  They are called ‘cedar’ elms for their propensity to grow in the same habitat as Ashe Junipers, which are colloquially (but incorrectly) called ‘cedars.’

Cedar Elm flowers.

Cedar Elm seeds (samaras).

Pollen plays a critical role in plant reproduction, and is a nutrient-dense resource for bees and other animals.  For humans, a vast number of crops depend on pollination for their existence, including one-third of the world’s food crops such as almonds, chocolate, and coffee.  Due to their regular reproduction cycles requiring pollen, plants sustain ecosystem services such as moderating temperature by providing shade and releasing moisture into the air, producing oxygen, stabilizing soil, and creating wildlife habitat.  That’s how pollen is positive for us and for the environment!

Charismatic Clematis

 

Scarlet Clematis is endemic to the southeastern Edwards Plateau.

Blooming vines are always a welcome addition to our Hill Country landscapes, offering continuous interest through vibrant colors and varied bloom times. Some of the most popular vines are in the genus Clematis in the Buttercup Family.  While many cultivars and hybrids exist, there are nine native species in Texas, the most prominent being Scarlet Clematis (Clematis texensis), Purple Leatherflower (Clematis pitcheri), and Old Man’s Beard (Clematis drummondii).

Otherwise referred to as Scarlet Leatherflower and Texas Clematis, Scarlet Clematis is a herbaceous to slightly woody vine, with compound leaves of four to five pairs of rounded leaflets, and grasping tendrils which allow the plant to climb to about 10 feet.  It has bell-shaped flowers, held in axillary clusters of one to seven, blooming only on new growth.  The four red to scarlet-colored ‘petals’ are actually thick, leather-like sepals slightly recurved at the tips, occurring from March to August.  A ball of feathery plumed seeds follows the floral display.  Scarlet Clematis is uncommon, found along streams and on limestone cliffs and rocky slopes and is endemic to only a few counties in the southeastern portion of the Edwards Plateau.

Scarlet Clematis Bloom

Feathery Plumed Scarlet Clematis Seedhead

Purple Leatherflower, also called Purple Clematis, Bellflower Clematis, and Pitcher’s Clematis, is a 10 foot or longer vine that climbs via twining petioles. Its compound leaves are also comprised of three to five pairs of pointed leaflets, each having a raised network of veins on the underside. From May to September, flowers appear on long, nodding stems arising from the leaf axils, and are dull purple on the outside and dark purple on the inside. The four petal-like sepals are thick and united at the base, but are recurved at the tips.  While they also turn into a ball of plumed seeds following flowering, they are the least pubescent of the native species.  Purple Leatherflower can be found in woodland edges and thickets in the central, south, and western parts of the state.

Purple Leatherflower

Purple Leatherflower Bloom

Plumed Purple Leatherflower Seedhead

Known as Texas Virgin’s Bower and Drummond’s Clematis, Old Man’s Beard is a climbing vine to 30 feet, coiling its petioles along fences and other structures and shrubs.  The compound leaves are composed of five to seven coarsely cut leaflets. From April to September, star-shaped blooms of four light greenish-yellow, almost white, narrow and thin sepals with slightly crinkled margins surround conspicuously long stamens. Old Man’s Beard can be found along roadsides and in rocky canyons in the central, south, and western parts of the state. One of its common names comes from the 2 to 4 inch long, silky hairs on the seed cluster, giving the plant a bearded appearance which often lingers into winter. Another comes from the abundant cascade of white flowers, believed to symbolize purity and innocence.

Old Man's Beard

Old Man's Beard Bloom

Beard-like Old Man's Bloom Seedheads

Flowering Clematis vines have been known to symbolize ingenuity, cleverness, and travel, due to their climbing, rambling nature.  In traditional Chinese symbolism they represent wisdom and foresight, and in Japanese Hanakotoba or the language of flowers, they represent moral beauty and the joy of travelers. The intricacies of their showy flowers and long blooming season make Clematis some of our most charismatic vines!   

Aerial Assassins

Robber Flies are also called Assassin Flies, and for good reason!

What is that powerfully built, fly-like creature that waits in ambush to catch their prey in flight? It’s a robber fly, otherwise known as an assassin fly, which feeds almost exclusively on other insects, including other flies, beetles, butterflies, moths, bees, ants, dragonflies, damselflies, wasps, grasshoppers, and even some spiders.

Robber flies have stout, spiny legs, short antennae, three simple eyes on the top of their head between two large compound eyes, bristly bodies, and a short, stout proboscis that encloses a sharp, sucking mouthpart called a hypopharynx. They also have a dense moustache of bristles on the face called the mystax, which appears to offer some protection from their struggling prey. These flies attack their prey by stabbing it with the proboscis and injecting it with a saliva that contains both a neurotoxin and proteolytic enzymes.  This paralyzes the prey and liquifies the insides, allowing the robber fly to suck the material up through their proboscis.

In spring and summer in our area, some of the more common robber flies include the Bee-like Robber Fly (Laphria macquarti), Prairie Robber Fly (Diogmites angustipennis), and the Maroon-legged Robber Fly (Promachus hinei). 

The Bee-like Robber Fly is large (up to 1.25” long), hairy, mostly black with a yellow thorax, basal abdominal segments, and some yellow on the legs.  It mimics the American Bumblebee, and while it prefers to feed on small beetles, it will take a wide range of prey, often perching on tree stumps in the open.

Bee-like Robber Fly

The Prairie Robber Fly, also called the Slender-winged Hanging Thief, is about 1” long, with greenish-red eyes, tan to reddish-brown body, thorax with darker brown longitudinal stripes, and abdomen with darker lateral stripes.  It is common in both woodland and meadows, hunting bees and other insects, and typically hangs from vegetation by its forelegs while it consumes its prey.

Prairie Robber Fly

Another large robber fly is the Maroon-legged Robber Fly, up to 1.5” in length.  It has dark eyes, light-colored bristles around the face, a brown thorax, a cream-colored abdomen with thick black bands and a black tip, and hairy reddish-brown legs. It prefers hunting bees and wasps, and can be found flying around a variety of habitats, perching on the ground or in vegetation.

Mating Maroon-legged Robber Flies

Female robber flies deposit tiny, whitish eggs on low-lying plants and grasses, or in cervices in wood or bark, or in soil. After hatching, the larvae live in this detritus, feeding on other soft-bodied insects. Robber flies overwinter as larvae, pupate in the soil, and eventually emerge as adults.  This developmental cycle can take one to three years, depending on the species and environmental conditions. Robber flies generally occur in relatively open habitats with scattered vegetation, or in forested margins and woodland edges.  

Robber flies are generally considered beneficial insects due to their predatory nature, as they primarily feed on other insects, many of which are considered pests. These aerial assassins help to naturally regulate insect populations thereby contributing to a more balanced ecosystem!