Friday, July 1, 2016

Summer Sulphurs


Orange Sulphur, Colias eurytheme, on Indian Blanket

The family of butterflies known as Pieridae includes the whites and sulphurs, our most conspicuous and abundant butterfly species. They easily draw the attention of even the most casual observer as they flit about our gardens, fields, and open habitats in summer.  Sulphurs are usually some shade of yellow, orange, or white, and avidly visit flowers.  Their uppersides often feature black borders or patterns and while they usually perch closed, these patterns can sometimes be seen faintly through the wing or glimpsed in flight. The most widespread sulphurs in our area include the Orange Sulphur (Colias eurytheme), Southern Dogface (Zerene cesonia), Little Yellow (Pyrisitia lisa), and Dainty Sulphur (Nathalis iole).  

Orange Sulphur, Colias eurytheme
White Female Orange Sulphur

Found throughout most of North America, the coloration of the Orange Sulphur can be quite variable, but the typical male has a yellow upperside with orange overlay, yellow veins, a wide black border, and a dark black cell spot.  Females can be yellow or white with an irregular black border surrounding several light spots.  Both sexes have a silver spot surrounded by two concentric dark rings and a spot above it on the underside of the hindwing. With a wingspan of about 1.5 to almost 3 inches, males patrol around for receptive females, who lay eggs singly on the leaf tops of host plants in the pea family, such as alfalfa and clovers.  Orange Sulphurs have 4 to 5 broods from March to November, and overwinter in the chrysalid form.

Southern Dogface, Zerene cesonia

The Southern Dogface is easily identified by both sexes having the shape of a yellow dog’s head surrounded by black on the upperside of their forewings, with the black and white ‘eye’ not touching the black border.  The underside of the hindwing in summer is pale to bright yellow, becoming tinged with pink markings in the fall.  With a wingspan of 2 to 3 inches, the males seek out females who lay eggs on the undersides of terminal leaves of host plants such as alfalfa, clovers, and indigo.  Three broods are produced almost year round, with adults overwintering in reproductive arrest during the coldest months.

Little Yellow, Pyrisitia lisa

As their name suggests, Little Yellow butterflies are on the small side with a wingspan of 1 to 2 inches.  The upperside of the male has a yellow forewing with a wide black tip or apex and a hindwing with a black border. While the female is usually yellow and sometimes white with black borders, both sexes usually have two tiny black dots at the base of the hindwing underside.  Four to five broods occur in the south, and females lay eggs singly on midveins or between leaflets of partridge pea, wild sensitive plants, and sennas.

Dainty Sulphur, Nathalis iole

A mating pair of Dainty Sulphur in winter form

Our smallest sulphur, the Dainty Sulphur, has a wingspan of ¾ to slightly over 1 inch, and is identified by a yellow upperside with black markings that are more extensive on the female.  The underside of the forewing has an orange or yellow patch near the base with a few strong black spots closer to the outer wing edge.  In summer, the hindwing underside is pale yellow, and turns to dusty green in winter.  Both males and females tend to fly low, rest with their wings closed and held perpendicular to sun’s rays to gather warmth, and overwinter in adult form.  Flying year round, the females lay single eggs on sneezeweed, dogweed, and other asters.
Send your nature-related questions to naturewatch@austin.rr.com and we’ll do our best to answer them.  Check out our book, Nature Watch Austin, published by Texas A&M University Press, and our blog at naturewatchaustin.blogspot.com if you enjoy reading these articles!




Tuesday, April 19, 2016

Mud Hens


American Coot, Fulica americana

Spend any amount of time observing wildlife around freshwater wetlands, swamps, marshes, suburban lakes, and sewage ponds, and you’ll no doubt see a Mud Hen or American Coot (Fulica americana).  Commonly mistaken to be ducks, coots belong to a distinct scientific order and differ significantly from other species of marsh birds.

An overall blackish, plump, chicken-like bird with a rounded head, red eyes, a sloping whitish bill with a dark band near the tip, and a small reddish brown forehead shield, coots swim like ducks but do not have webbed feet like ducks.  Their yellow-green legs end in long toes with broad lobes of skin on either side that help them kick through the water.  Each time the bird lifts its’ feet, the lobes fold back to facilitate walking on dry land.  Their tiny tails and short wings make them awkward and clumsy fliers, and they often require many wing beats and long running takeoffs to get airborne. Coots mainly eat aquatic plants and can dive in search of food, but they can also forage and scavenge on land for terrestrial plants, arthropods, fish, insects, and mollusks.  

Note the lobed feet on this perching American Coot

Mating season occurs in May and June, with coots requiring heavy stands of aquatic vegetation along a shoreline with some standing water within those stands.  It is here that they make their nests, which consist of multiple structures used as display platforms, egg nests, and brood nests. Egg nest material is woven into a shallow basket and lined with finer grasses to hold the eggs. The entire nest is anchored to upright plant stalks and is generally a floating structure.  Females deposit eggs between sunset and midnight, one per day, until the average clutch of 9 eggs is complete. Both males and females share the 21-day incubation responsibility.  


Being persistent re-nesters, coots will replace lost clutches within 2 days during the deposition period.  Additionally, once hatching begins and a certain number of chicks are present, coots will abandon the remaining eggs.  Unlike the drab color of the adults, coot chicks are quite colorful, having conspicuous, orange-tipped, ornamental plumes covering the front half of their bodies, often referred to as ‘chick ornaments.’   While these plumes get bleached out after about 6 days, experiments have shown that chicks with more of this ornamentation are given preferential treatment by their parents. The oldest known coot lived to be more than 22 years old.

In winter, coots can be founds in large groups or ‘rafts’ of mixed waterfowl and in groups numbering thousands of individuals.  They can consume very large amounts of aquatic vegetation, but because they live in wetlands, they can accumulate toxins from pollution sources including agricultural runoff, industrial waste, and nuclear facilities.  As such, scientists monitor coots as a way of measuring the effect these toxins have on the health of the environment at large.   

Thursday, February 11, 2016

Fabulous Foxes


Gray Fox, Urocyon cinereoargenteus

Members of the Canidae family are all dog-like mammals, and in the United States that includes wolves, coyotes, domestic dogs, and true foxes.  They are adapted to running swiftly over open terrain, and typically have long muzzles, upright ears, bushy tails, and teeth that can crack bones. The family is further divided into two tribes, with the wolves, coyotes, and dogs in the Canini tribe, and the true foxes in the Vulpini tribe.  In central Texas, two species of true foxes exist, the native Common Gray Fox (Urocyon cinereoargenteus) and the introduced Red Fox (Vulpes vulpes).  


Gray Fox, Urocyon cinereoargenteus
Most active at night, and sometimes in late afternoon or early morning, the Gray Fox is a medium-sized fox with grayish upperparts, tawny sides, and reddish-brown legs.  It has a whitish throat with a distinct black patch on the sides of its muzzle and lower jaw.  Often confused with the Red Fox, the main distinction is the black tip on the tail and the fact that it is found throughout Texas.  Gray Foxes are adept tree climbers, highly unusual for Canids, and they use their rounded claws to ascend trees much like bears.  Once up in the canopy, they can hunt birds, escape predators, bask in the sun, or jump from branch to branch like a cat.

Also active at night, and frequently at dawn and dusk, the Red Fox is similar in size to the Gray Fox, but differs mainly in its coloring.  While its typical coloration is generally rusty red, this fox can exhibit several other color forms, from black to silvery gray, but it always has a pattern of darker fur along the spine and down across each shoulder blade, forming a cross.  The most distinct difference from the Gray Fox is the bushier tail that ends in a white tip.  The Red Fox is found throughout most but not all of Texas, absent from the far western and southern portions of the state.  Not native to Texas, it was introduced for sport around 1895 in the eastern and central regions. 

Red Fox, Vulpes vulpes

Both species of fox are social animals, and their primary unit consists of a family with an adult male (or Reynard or dog), adult female (or vixen), and the juveniles (or kits, cubs, or pups) that were born that year.  These foxes are thought to mate for life, with breeding beginning in December and extending into February.   They can use a variety of places for denning sites, but most commonly they reuse underground burrows dug by other animals.  Both the male and female care for and feed their young, and their diets consist of small mammals, birds, berries, and occasionally insects.

Foxes are usually seen in mixed woodlands and edges of forests, and while hunting they often use old roads or open trails while traveling the same routes.  Their activity peaks with the activity of their prey, and if you get the chance to watch the cunning way in which they hunt, using their night vision, acute hearing, and high pouncing attacks, you’ll begin to understand why they are called fabulous foxes!



Saturday, December 12, 2015

Likin' Lichens


A fruticose Slender Orange Bush Lichen, Teloschistes exilis, makes
its home among various foliose lichens.


What lies beneath our feet and in front of our eyes, typically small and unassuming, sometimes brightly colored, but always waiting patiently for their contributions to take hold?  Lichens! Composite organisms made up of a fungus and a photosynthetic partner, most commonly an algae, lichens are ecosystem pioneers.  They break down rock surfaces and prepare areas for mosses, grasses, and trees to follow.  Certain species that also contain cyanobacteria can improve the fertility of the soil by adding necessary, usable nitrogen, and many species are used as bio-indicators of air quality.  They are also highly efficient collectors of airborne substances, and recycle these substances into the soil.  Historical uses for lichens include food, natural dyes, and herbal remedies. 

Mexican Yolk Lichen, Candelina submexicana, is a good example of a crustose lichen.

Lichens can be observed in many places, including on the ground, on rocks, and on trees.  The surface, or substrate, on which they are found provides a place for them to attach and grow.  Some species are substrate-specific while others can grow on a wide variety of substrates.  Ground substrates can include sand, soil, mosses, and downed decomposing logs.  These lichens act as soil stabilizers and contribute to soil fertility.  Rock substrates include natural substances like cliffs, talus slopes, boulders, and pebbles, and man-made substances such as concrete and roof shingles.  Lichens on rock substrates often colonize the rock and act as decomposers, turning it into soil.  Tree substrates include both deciduous trees such as oaks and conifers such as firs, cypresses, junipers, and pines.  Older trees often have a greater diversity of lichens, partly due to a more fissured bark that has a specific texture, chemistry, and moisture-holding capacity.  

Cumberland Rock-shield Lichen, Xanthoparmelia cumberlandia, is a type of foliose lichen. 

Lichens are mostly commonly divided into three growth forms: crustose, foliose, and fruticose. Crustose lichens look like they are spray-painted on their substrate, and their lower surface or ‘medulla’ is the same color as and blends into that substrate.  Foliose lichens are leafy growths with distinct lobes, and their medulla is a different color.  Fruticose lichens are often bushy or shrubby growths, and can be highly variable.  They often form obvious disk or cup-shaped structures called ‘apothecia.’  

Western Antler Lichen, Pseudodevernia intensa,
is a fruticose lichen.
Sundew Beard Lichen, Usnea cirrosa, shows
off its apothecia.

As composite organisms, lichens have been used worldwide as indicators of air quality.  They are very sensitive to the presence of low levels of sulfur, nitrogen, and fluorine-containing pollutants that adversely affect their community composition, growth rates, reproduction, biomechanics, and appearance.  By concentrating a wide variety of pollutants in their tissues, they act as pollution monitors, and are the subjects of many biomonitoring studies regarding air quality and climate change being conducted jointly by the U.S. Forest Service and the Environmental Protection Agency.  Since lichens are long-lived, can be observed in the field in any season, and with many species having extensive geographical ranges, they allow for changes in pollution to be studied over large areas and long periods of time.

As you can see, the lichen has almost all it needs to survive.   While most species of lichens grow very slowly, they all require a proper substrate, clean air, moisture, sunlight, and warmth to thrive. Turning air into life, they are truly one of nature’s alchemists!

Wednesday, November 18, 2015

The Seven-faced Bird



Most often, the traditional star of holiday meals in the United States is the domestic turkey. Interestingly, this bird is only one of two wild bird species native to North America (the other is Muscovy Duck) that have been bred specifically for human consumption.  Wild turkeys (Meleagris gallopavo) were first domesticated in Mexico, and then exported to Europe.  European settlers brought domesticated turkeys back to the New World, but would also hunt the wild birds they found.  Currently, there are more than 7 million wild turkeys in North America, a pretty astounding fact when they were almost extinct by the 1930s due to overhunting and deforestation of their preferred habitat.

Adult wild turkeys are large birds with long reddish-yellow to grayish-green legs, with each foot having three toes in front and a shorter, rear-facing toe in back.  Their body feathers are generally blackish to dark brown, with a coppery sheen that becomes more pronounced in mature males. The toms or gobblers, as the males are called, have a large, featherless, reddish head, red throat, and red wattles on both the throat and neck.  The long, fleshy object hanging over the male's beak is called a ‘snood’, and the tail feathers are all one length.  Juvenile males are called jakes, and they have shorter wattles and a tail fan with longer feathers in the middle.  Males also have a spur behind each of their lower legs, which they use when fighting.  Wild turkeys show a strong sexual dimorphism, with the males being significantly larger than the females or hens.  The hens have duller feathers overall, mainly in shades of brown and gray.  Young females are called jennies, and the very young of both sexes are called poults.


In Japanese and Korean, the turkey is called 'shichimencho' and 'chilmyeonjo' respectively, both of which translate to 'seven-faced bird.'  This reflects the ability of the male wild turkey to change the color of its facial skin and wattles in a matter of seconds due to excitement or emotion.  While the birds' head color can range from red to pink to white to blue, certain changes represent certain moods.  When the male is excited his head turns blue, and when he is ready to fight it turns red. 

Unlike their domestic counterparts and despite their weight, wild turkeys are agile fliers.  While their powerful legs can get them running up to 25 mph, their top speed in flight is 55 mph. In their ideal habitat of open woodland or wooded grasslands, they fly beneath the canopy top and sleep up in trees.  They can live an average of 3-5 years in the wild, eating a varied diet that includes grains, insects, berries, and even small reptiles.  Their daytime vision is three times better than a human's and they see in color, but they have poor vision at night.    

There are 6 different subspecies of wild turkey in North America, showing differences in coloration, habitat, and behavior.  In our region, the Rio Grande Wild Turkey (M. g. intermedia) is dominant, naturally ranging through Texas to Oklahoma, Kansas, New Mexico, Colorado, and Oregon. Having slightly longer legs than other subspecies, it is better adapted to a prairie habitat, with a more greenish-coppery sheen and buff-colored feathers on the tail tips and lower back.  This subspecies prefers brushy areas near streams or rivers, and forests of scrub oak, pine, and mesquite.

Either way you slice it, as you celebrate the holidays this year, reflect on the wonders of the 'seven-faced bird,' appreciate their history with humans, and keep an eye out for wild wattle and snood!

Sunday, November 1, 2015

Gone to Seed



Scarlet Leatherflower, Clematis texensis

Often used as an informal figure of speech meaning to deteriorate or go downhill, ‘gone to seed’ can have a negative connotation.  But each seed contains a new beginning: a tiny plant just waiting for the right conditions such as water, warmth, and a good location, to germinate and grow.  Seeds and seed heads form fascinating shapes, varying sizes, and intricate patterns, often adorning the fall and winter landscape.

Illinois Bundleflower, Desmanthus illinoensis

Inland Sea Oats, Chasmanthium latifolium

Plants have many ways of dispersing their seeds, and most have evolved over millions of years. While the methods are tried and true, certain seeds have developed in very particular ways to take advantage of such methods, and some plants only release their seeds in response to specific triggers. 

Wafer Ash, Ptelea trifoliata

Texas Milkweed, Asclepias texana

Wind helps seeds float or flutter away, often aided by seed structures such as thin wing extensions or long, feathery tails like those on the endemic Scarlet Clematis (Clematis texensis).  Texas Bluebonnets (Lupinus sp.) employ the expulsion or explosion method, where the small, pebble-like seeds are forcibly expelled when the dried pods twist open in the warm sun.  Gravity plays a part in many plants seed dispersals, where weighty seeds fall off the plant and roll to a new location.  The best example of this are the round, heavy fruits that simply fall off a plant when ripe, such as those on Mexican Plum (Prunus mexicana) or Texas Persimmon (Diospyros texana).  If the fruits have a tough outer shell, they may travel some distance from the parent plant, and if they have a soft skin, they may break open where they fall and scatter the seed or seeds within. 

Texas Persimmon, Diospyros texana

Mexican Buckeye, Ungnadia speciosa

Some plants produce very light seeds, seeds with buoyant fluff, or seeds with air trapped in them, so they can float away from the parent plant that grows in or around water, like Common Buttonbush (Cephalanthus occidentalis) or Black Willow (Salix nigra).  Others employ the assistance of animals, which can come in the form of seed or fruit eating (where the seed can pass undigested through the animal), seed caching or burying, or seed transportation.  Often unbeknownst to the animal, seeds can be covered with tiny hooks or spines that catch on a passing animal’s fur, and eventually rubbed off in another location.  Common examples include Cedar Waxwings and American Robins eating juniper and yaupon berries, both ground and tree squirrels eating and caching acorns, and many animals (including humans) that emerge from the wilds carrying the seeds of Beggarsticks (Bidens sp).    

Yaupon, Ilex vomitoria

This fall and winter, let the seeds linger! Not only do they provide much needed food for wildlife, but leaving them allows for some beautiful and mysterious patterns in your winter landscape, and the promise of renewing the cycle of life that begins again each spring!



Tuesday, October 13, 2015

Fields of Gold


Prairie Goldenrod, Solidago nemoralis

Cooler temperatures and shorter days mark the onset of autumn, and the golden colors of the season begin to surround us.  Among the amber and scarlet hues making an appearance in the landscape, one cannot help but notice two of our most common fall-blooming native plants: Goldeneye (Viguiera dentata) and Prairie Goldenrod (Solidago nemoralis).  

Goldeneye, Viguiera dentata

A member of the sunflower family, Goldeneye is a bushy, drought-tolerant, multi-branched plant that tends to grow in colonies, providing rich swaths of golden color along our roadsides and in open areas.  It has narrow leaves and numerous 1.5 inch daisy-like flowers at the tips of long, slender stalks.  Growing to 3 feet tall in full sun or up to 6 feet tall in partial shade, this plant is native not only to Texas but to Arizona and New Mexico as well.  It prefers relatively dry, partially shaded areas such as woodland edges and open prairies, and in Mexico is also known by the common name Chimalacate.  



The mid to late fall blooms of Goldeneye not only provide seasonal color, but provide for native wildlife as well.  Goldeneye is the larval food plant for both the Bordered Patch and Cassius Blue butterflies, and if spent flower stalks are left to stand through most of the winter, they will provide good seed forage for Lesser Goldfinches and other birds.  Infusions of this plant are still used today as an antibacterial treatment for baby rash.  


Prairie Goldenrod, Solidago nemoralis

Prairie Goldenrod, also called Gray Goldenrod, is a slender-stemmed plant 1.5 to 2 feet tall, that blooms from June through October.  A member of the aster family, it has thin, coarsely-toothed leaves and yellow flowers that are borne on the upper side of hairy stalks, arching out and downward to create a vase-shaped flower cluster.  Individual plants bloom at various times, extending the flowering season, but they are most noticeable in fall, especially when paired with purple Gayfeather and red Autumn Sage.  An excellent addition to a wildflower meadow or a sunny garden, Prairie Goldenrod is naturally found in dry, open woods and upland prairies, and does well in full sun to part shade. A carefree plant, it can become invasive if left alone, but is also easily controlled.  



Of special value to bees and butterflies for its pollen and nectar, and to several species of finches for its seeds, Prairie Goldenrod was also used by Native Americans to treat jaundice and kidney disorders, and as a wash for burns and skin ulcers.  The Navajo burned the leaves as incense, and used the seeds for food.

As you wander along roadways and pathways this fall, admire these fields of gold that delight not only our senses, but provide a bountiful harvest for our wild neighbors as well!