Poisonous or Venomous?

Poison Ivy

Often used interchangeably when describing some plants and animals, in reality poisonous and venomous mean two different things.  Poisonous describes plants or animals that are harmful when consumed or touched.  Venomous refers to animals that inject venom into their prey, by means of a bite or sting, when hunting or for self-defense.  To add to the confusion, all venoms are a poison but not all poisons are venoms!

Poisonous species typically produce a toxin that can range from irritant to fatal. Plants such as Poison Ivy (Toxicodendron radicans) and some members of the Spurge family are considered irritants when they come in contact with skin, but this effect is produced through different mechanisms.  Nearly all parts of the Poison Ivy plant contain urushiol, which is a substance that gives us contact dermatitis, or a severely itchy and painful inflammation of the skin.  

Texas Bull Nettle

Spurges such as Texas Bull Nettle (Cnidoscolus texanus) and Betonyleaf Noseburn (Tragia betonicifolia) have raised structures called trichomes that are capable of ’stinging' animals and humans that brush against them.  These plants have trichomes on their leaves and stems that have bulbous tips that break off and reveal needle-like tubes that pierce the skin. They can cause an itching, burning rash by emitting onto the skin a mix of acetylcholine, formic acid, histamine, and serotonin.  

Jimsonweed or Sacred Datura

One local native plant, Jimsonweed or Sacred Datura (Datura wrightii) goes well beyond irritant to hallucinogenic and even fatal if ingested.  All parts of this plant contain toxic alkaloids, and the narcotic properties of this plant have been known by humans since before recorded history.  They once figured prominently in important religious ceremonies of various southwestern Native American tribes.

Gulf Coast Toad

Animals that are poisonous include most amphibians (frogs, toads, salamanders, and newts), that have some amount of toxins on their skin and within other tissues. Special skin glands produce useful proteins, some for use in respiration, others for fighting bacterial or fungal infections, and at least one in each species that is used for defense.  For example, many toad species will release their toxins when they feel threatened, such as when they are caught by a dog or cat, and can trigger drooling, vomiting, and respiratory or cardiac problems.

Western Diamondback Rattlesnake

While some snakes are the most commonly known venomous animals, all spiders, some lizards, and many bees, ants and wasps are venomous as well.  The venoms they inject through a bite or sting contain various classes of toxins designed to perform specific biological effects such necrosis or death in multiple cells (necrotoxins) or individual cells (cytotoxins), disruption of the nervous system (neurotoxins), or damage to muscle tissue (myotoxins).   The venom of our Western Diamondback Rattlesnake (Crotalus atrox) carries both necrotoxins and myotoxins, Black Widow spiders (Latrodectus macrons) carry both neurotoxins and cytotoxins, and Striped Bark Scorpions (Centruroides vittatus) and Texas Redheaded Centipedes (Scolopendra heros) carry neurotoxins.

Striped Bark Scorpion

Texas Redheaded Centipede

While the vast majority of snake toxins are transferred by bite, one exception includes garter snakes (Thamnophis sp.), which are small and harmless in terms of their bite but are toxic to eat because their bodies absorb and store the toxins of their amphibious prey.  In our area, these snakes include the Black-necked Garter Snake (T. cyrtopsis) and the Western Ribbon Snake (T. proximus).

Western Ribbon Snake

It is important to keep in mind that many plants and animals that are poisonous or venomous are not necessarily a guaranteed threat to humans, as much depends on how the plant or animal is encountered, its toxicity level, and the amount of toxin absorbed.  Regardless, respecting these species and giving them their space is the cardinal rule.  Interestingly, the medicinal use of venoms for therapeutic benefit in treating diseases dates back to 380 B.C. in ancient Greece.  Today, the venoms produced by different organisms, which contain hundreds of different bioactive elements, are isolated, purified, and screened, then studied to identify components that may have desirable therapeutic properties.  This research is often the starting point for developing a therapeutic drug, and those types of drugs on the market today are used to lower high blood pressure, relieve severe pain, act as blood thinners, treat Type 2 diabetes, and stop bleeding during surgical procedures.

Royal Ruse

Monarch

As spring unfolds in Central Texas, butterflies begin to appear ever present in our gardens and landscapes.  A subfamily of the Brushfoot butterflies, milkweed butterflies are a group of butterflies whose larva feed only on various milkweed species, and these plants provide the adults with certain chemicals that make them naturally distasteful to most predators.  This subfamily is composed of ‘the royals’, better known as the Monarch (Danaus plexippus), Queen (Danaus gilippus), and Soldier (Danaus eresimus).

Monarch ventral, or underside.

The well-known Monarch is probably the most famous butterfly in North America, but it often confused with the Queen and Soldier.  Monarchs have rich cinnamon-orange wings with distinctive bold black veins and white dots on the black wing borders and on the black body, and look remarkably similar on the underside.  Its larva are striped with yellow, black, and white, and they have two sets of black tentacles rising from their bodies.  

Queens mating, showing their undersides

While the underside of the Queen butterfly can look a lot like a Monarch, it is its upperside that allows for a definitive identification.  Queens can appear almost solid orange compared to stained glass pattern of the Monarch, having rich dark orange wings that lack the black veining and white spots toward the dark wing tips and along their black edges. While adult Queens seek out ageratum, eupatorium, and heliotrope as preferred nectar flowers, adult Monarchs are much broader generalists in terms of their use of many types of nectar plants.

Queen dorsal or upperside, showing white spots along forewing

Soldier dorsal or upperside, showing absence of white spots along forewing
and more obvious wing veining

Soldiers typically occur where Queens are common and are often overlooked due to their very similar appearance.  They can be properly identified by fewer white spots and more obvious dark wing veining on the forewings than on the Queen, but less defined veining than on the Monarch.  Another clue is that Soldiers generally fly in our area in late summer and fall.  Both Soldier and Queen larva are Monarch look-alikes, sporting yellow, black, and white stripes, but with three sets of black tentacles instead of two.

Viceroy dorsal or upperside, showing black band across middle of the hindwing

In an action intended to deceive, the Viceroy (Limenitis archippus) is a milkweed butterfly mimic, using its similar patterning and color to trick predators into thinking it is just as distasteful.  Viceroys are smaller than Monarchs or Queens and usually have a black band across the middle of each hindwing.  This band can be faint or missing, but this butterfly can also be identified by its flying style of quick flaps and flat-winged glides, rather than flying strongly with wings in a shallow V-shape like the Monarch and Queen.  One more way that you can uncover this butterfly’s royal ruse is by knowing that its host plant is willow and not milkweed, and its larva resemble a horned bird-dropping.

Take a closer look the next time you see an orange butterfly on the wing.  It might just be a Monarch heading north, or a Queen or Soldier nectaring on mistflower, or maybe even a Viceroy trying to pull off a royal ruse!

Day Fliers

Eight-spotted Forester nectaring on Mexican Plum

As part of the larger groups of moths known as the Noctuidae and Thyrididae, Forester and Window-Winged moths are day fliers that commonly have white-spotted black forewings and either similar or bright orange hindwings, and are often found in open woodlands and flowery meadows.  This time of year, you can frequently spot them nectaring on early blooming trees and shrubs, including Mexican Plum, Escarpment Black Cherry, Texas Redbud, and Mexican Buckeye.

A newly emerged adult Eight-spotted Forester

In our area, the Eight-spotted Forester (Alypia octomaculata), Grapevine Epimenis (Psychomorpha epimenis), and Mournful Thyris (Pseudothyris sepulchralis) are the more typical species to be found.  The Eight-spotted Forester has velvety black wings with two large cream-colored spots on each forewing and two large white spots on each hindwing, alluding to its ‘eight-spotted’ common name.  It has a wingspan of about one and a half inches, and its legs are adorned with showy orange tufts where they attach to its body.  Flying from March to June with a second brood in August, the larva of this moth have broader orange bands with black dots, alternating with fine black and white stripes, and an orange head and hind end.  They feed mainly on Virginia Creeper and other various grapevines.

Eight-spotted Forester caterpillar

Grapevine Epimenis nectaring on Mexican Plum

Grapevine Epimenis is another Forester moth that also has velvety black wings, but each forewing has one bold white patch near the outer edge, and each hindwing has a broad orange-red band.  With a wingspan of about one inch, it flies from February to April, and sometimes has a second brood in October.  Its larva feed on various grapevines, most notably Mustang Grape in Central Texas, and are mainly black and white striped with an orange head and hind end.

Mournful Thyris nectaring on Mexican Buckeye

Mournful Thyris is a Window-Winged moth, a chunky-bodied small moth with just under a one inch wingspan, that habitually spreads its wings when alighting on flowers or on wet sandy soils along forest trails.  Its wings are black patterned with multiple various sized white spots, and translucent median patches that form ‘windows.’  It flies from February to April, and its larva also feed on grapevines, most commonly Mustang Grape in our area.

Contrary to popular belief, a surprising number of moth species are day fliers, and many are as beautifully patterned as, and often mistaken for, butterflies.  If you’d like to attract these splendid little moths to your yard, simply plant the native trees, shrubs, and vines listed above, and they will grace you with their presence each spring!

Plant Natives!

Non-native, invasive, Nandina - Please avoid planting this and consider removing it from

your landscape.  It is a pest in our parks and preserves.

Spring is the ideal time to think about planting, and how you manage your garden or landscape can have an effect on the overall health of the soil, air, water and habitat for native wildlife as well as our human community. Help conserve and improve the quality of these resources by using sustainable gardening practices such as mulching and composting, reducing or eliminating lawn areas, xeriscaping (planting native, drought-tolerant plants), installing rain barrels, and removing non-native invasive plants and restoring native ones.

The U.S. government defines an invasive plant species as one “that is not native to the ecosystem under consideration and whose introduction is likely to cause economic or environmental harm or harm to human health.” These species grow outside desired boundaries, out-competing native species, and spread by seeds, berries, spores, runners, rhizomes, and stems. Some can be easily transported long distances, and every year millions of our tax dollars and thousands of volunteer hours are spent trying to eradicate them.

Many of these plants have already invaded our preserves and greenbelts in Austin, originating in our landscapes, escaping cultivation and spreading into the wild. Invasive species may grow faster, taller, or wider and shade out native species. Many stay green later into the season or leaf out earlier, giving them an advantage over natives. They can change the vertical and horizontal structure of ecosystems, alter hydrology, and disrupt nutrient cycles, all of which can have devastating effects on native plants and animals.

Although invasive exotics may offer birds fruit, squirrels nuts, and hummingbirds and butterflies nectar, they do not provide the entire range of seasonal habitat benefits that an appropriate locally native species will provide. If we want not only to satisfy our desires to attract wildlife, but also to restore the critical, often unseen, small pieces in our ecosystems, we need to bring back our locally native plants. These plants are not only attractive to humans, they also meet the food and cover needs of all wildlife species: bees, wasps, butterflies, grasshoppers, bugs, beetles, spiders, and thousands of others that sustain and support food webs which songbirds, salamanders, bats, toads, and box turtles more visibly demonstrate.

Escarpment Black Cherry is a beautiful native tree that makes a great replacement for the

highly invasive privets or ligustrums.

Aside from attracting a diversity of wildlife, the use of native plants minimizes the impact our landscapes have on the natural environment around us. They reduce water consumption, eliminate the need for chemical fertilizers and pesticides, and limit the competition from invasive exotics. This results in a much healthier habitat—water, soil, and air—for humans and animals alike, and is less costly, too. Invite wildlife to put on a show in your backyard by replacing the invasives in your landscape, and encourage your neighbors to do the same.

Non-Native/Invasive Plant(s)	Some Native & Adapted Alternative(s)
Bamboo	Wax Myrtle (Morella cerifera) Yaupon Holly (Ilex vomitoria) Bamboo Muhly (Muhlenbergia dumosa)
Chinaberry	Chinquapin Oak (Quercus muehlenbergii) Texas Red Oak (Quercus buckleyi)
Chinese Tallow Tree	Bigtooth Maple (Acer grandidentatum) Lacey Oak (Quercus laceyi)
Elephant Ear	Arrowhead (Sagittaria latifolia ) Crinum Lily (Crinum americanum) Pigeonberry (Rivina humilis) Frogfuit (Phyla nodiflora) Horseherb (Calyptocarpus vialis)
Giant Cane	Roughleaf Dogwood (Cornus drummondii) Yaupon Holly (Ilex vomitoria)
Japanese Honeysuckle	Coral Honeysuckle (Lonicera sempervirens) Passion Vine (Passiflora foetida or incarnate or lutea or tenuiloba) Rock Rose (Pavonia lasiopetala)
Holly Fern	River Fern (Thelypteris kunthii)
Kudzu, English Ivy, Vinca	Virginia Creeper (Parthenocissus quinquefolia) Trumpet Vine (Campsis radicans) Coral Vine (Antigonon leptopus)
Ligustrum (all species) or Common Privet	Evergreen Sumac (Rhus virens) Barbados Cherry (Malpighia glabra) Yaupon Holly (Ilex vomitoria) Possumhaw Holly (Ilex decidua) Texas Sage (Leucophyllum frutescens) Cherry Laurel (Prunus caroliniana) Black Cherry (Prunus serotina)
Mimosa	Desert Willow (Chilopsis linearis) Texas Redbud (Cercis canadensis var. texensis  ) Elbowbush (Forestiera pubescens )
Nandina or Heavenly Bamboo	Texas Lantana (Lantana urticoides) Bush Germander (Teucrium fruticans) Texas Sage (Leucophyllum frutescens)
Paper or White Mulberry	Red Mulberry (Morus rubra) Texas Persimmon (Diospyros texana) Possumhaw Holly (Ilex decidua) Cherry Laurel (Prunus caroliniana)
Pyracantha	Yaupon Holly (Ilex vomitoria) Possumhaw Holly (Ilex decidua) Evergreen Sumac (Rhus virens)
Red-tipped or Chinese Photinia	Evergreen Sumac (Rhus virens) Carolina Buckthorn (Frangula caroliniana) Yaupon Holly (Ilex vomitoria)
Russian Olive	Texas Persimmon (Diospyros texana)
St. Augustine Grass	Buffalo Grass (Bouteloua dactyloides)
Tamarisk or Salt Cedar	Bald Cypress (Taxodium distichum) Arizona Cypress (Cupressus arizonica)
Tree of Heaven	Chinquapin Oak (Quercus muehlenbergii) Lacey Oak (Quercus laceyi)
Vitex or Chastetree	Texas Pistachio (Pistacia mexicana) Mexican Buckeye (Ungnadia speciosa)
Wisteria	Passion Vine (Passiflora foetida or incarnata or lutea or tenuiloba) Trumpet Vine (Campsis radicans)

Early Spring Heralds

Windflower, typical white form

February is a time of change in Central Texas, with temperatures often ranging from the 30s to the 70s, and it is precisely these large swings in temperature that create challenges for local wildlife. Finding food is essential, and the little things like insects that emerge in early spring rely heavily on the early bloomers in our native landscape.

Elbowbush

Elbowbush (Forestiera pubescens), also commonly called Stretchberry or Spring Herald, is a multi-branched deciduous shrub with smooth gray bark, long arched branches, and light green leaves.  It is most conspicuous, though, in late January and early February, when small, yellow-green, petal-less flowers begin to burst in small clusters on the bare twigs. Common in open woodlands, brushy areas, and near streams, its early flowering period provides nectar for native bees and spring butterflies, namely Gray, Juniper, and Great Purple Hairstreaks.  Elbowbush gets its common name from branches that typically form in right angles to one another, reminiscent of a bent elbow.  It produces a quarter-inch, fleshy, dark blue fruit often devoured by wildlife in the summer, and its leaves turn a unique chartreuse color in the fall.  Additionally, Elbowbush is one of the larval food plants for the Incense Cedar Sphinx (Sphinx libocedrus). 

Two-flowered Anemone, exhibiting side stem

Poking their colorful blooms above the drab winter landscape are two species in the Buttercup Family,  Two-flowered Anemone (Anemone edwardsiana) and Windflower (Anemone berlandieri). While both of these plants bloom from February to April, Two-flowered Anemone is an uncommon plant that is also called the Edwards Plateau Thimbleweed, since it grows only in this region of Central Texas.  Windflower is common and has a more widespread range, and is often called Southern Anemone or Tenpetal Anemone (even though it can have 10 to 20 petal-like sepals).

Two-flowered Anemone, deep blue form

Two-flowered Anemone grows 6 to 12 inches tall, and is most often found on the moist banks of shaded canyons.  Midway or further up the stem are three bracts, with side stems growing from those bracts, and each side stem can produce 1 to 3 flowers, with only 1 flower on the main stem. In reality, most plants carry only 2 or 3 flowers in total, each 0.5 to 1.25 inches wide and typically white, but can exhibit pink, lavender, light blue, or deep blue. In comparison, Windflower grows 6 to 15 inches tall, with low-lying leaves that are divided into three segments and are often reddish-purple on the underside.  Its single stem carries only 1 flower, 0.75 to 1.5 inches wide, and it can exhibit the same range of colors as the Two-flowered Anemone. 

Windflower, pink form

Windflower, light blue form

Found on the moist soils in shaded canyons in the southern half of the Hill Country, Golden Groundsel (Packera obovate) is a rosette-forming perennial that blooms from February to April. Slender flowering stems rise up to 18 inches above the basal rosette of oval leaves, topped with yellow flower clusters few to many-headed, with each flower 0.5 to 0.75 inches wide.  Once established, this plant colonizes quickly, and can create an early-blooming, evergreen ground cover in shady, woodland areas.

Golden Groundsel

Why not plant some these early bloomers in your landscape, as they not only provide early nectar for bees and butterflies, but they are also heralds of our coming spring!

Bag Ladies

Bagworm on Crepe Myrtle

While winter is the time of year when we hang man-made ornaments on our trees and shrubs to commemorate the holiday season, it is also the time of year when nature-made ornaments are most apparent in the landscape.  These ornaments are as widely unique as snowflakes, and their appearance varies with the bits and pieces of leaves, twigs, and bark fragments woven into silken bags in a shingle-like fashion.  They reveal themselves on the bare branches and limbs in winter, and they are created by female bagworms.

Bagworm on Anacacho Orchid Tree

Members of the Psychidae family, there are about 1,350 species of bagworms worldwide, also commonly known as bagworm moths or bagmoths. Although different bagworm species vary slightly in habits and life cycle, bagworms spend the winter months in the egg stage sealed within the bags produced by females the previous fall.  

In late May to early June, very tiny caterpillars hatch, produce a silken strand by which the wind can carry them to new foliage (called 'ballooning'), and construct a tiny conical bag carried upright with them as they move.  During leaf-feeding, the caterpillars emerge from the top of the bag and hang onto the host plant with their legs, sometimes aided with a silken thread. The bottom of the bag remains open to allow fecal material (called ‘frass’) to pass out of the bag. 



By August or September, fully grown caterpillars have developed larger bags, and pupate within them.  Seven to 10 days later, the pupae of the male moths work their way out of the bottom of the bag, and emerge from their pupal skin.  These males have half-inch long clear wings, feathery antennae, hairy black bodies, and they spend their time seeking out a female to mate.  Females, on the other hand, are immobile and stay in the larval stage, do not develop into moths, and remain inside the bags. After mating, the females produce a clutch of 500 to 1000 eggs inside their bodies and then die.    



Bagworm on Juniper

Bags vary in size, up to 2 inches long and about a half inch wide, and are spindle-shaped.  They can be quite ornamental, covered in a somewhat patterned array of bits and pieces of plant matter.  A wide range of broadleaf and evergreen trees and shrubs serve as hosts for bagworm species, including juniper, cedar elm, bald cypress, live oak, persimmon, sumac, sycamore, willow, yaupon, and native fruit and nut trees.  

Since these bags are composed of silk and plant materials, they are naturally camouflaged from predators such as birds and other insects.  While birds can eat the egg-laden bodies of female bagworms after they have died, the eggs are very hard-shelled and can pass through the bird's digestive system unharmed.  This represents yet another way to disperse bagworm species over a wide-ranging area, and helps in creating a whole new generation of bag ladies!

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!