Color Changers

 

Green Anole, Anolis carolinensis

Native to North America and most abundant from the Carolinas south to Florida, along the Gulf Coast, and as far west as the Texas Hill Country, the Green Anole (Anolis carolinensis) is a small to medium sized lizard with a long, pointed head, slender body, long tail, and toes with adhesive pads that facilitate climbing.  Arboreal in nature, it can also be seen on the ground and in areas with shrubs and vines at the edge of our moist forests.

Males are typically 15% larger than females, from 4.9 to 8 inches long, with about 65% of that length being tail. Males have a dewlap or throat fan that is three times the size of the females and is strawberry-red, while the females’ dewlap ranges from white to light pink.  Unlike males, females also have a prominent white stripe that runs along their spine.

Male Green Anole with dewlap extended

Strongly territorial, males will fight other males to defend their territory, and have even been known to fight their own reflection in mirrored glass. When a male sees a rival, he will compress his body, extend his dewlap, inflate a dorsal ridge, and bob his head to chase off the intruder.  If that doesn’t work, they will fight, especially during mating season. A male’s territory typically includes two to three females, and he will court a female by extending his dewlap and bobbing up and down, mimicking a push-up. 

Breeding begins in April and ends in late September, with females laying their first clutch of one or two eggs about a month later.  Females can produce an egg every two weeks during mating season, up to about ten eggs, and they are buried in a shallow depression in soft soil or leaf litter.  Eggs are incubated by the heat of the sun, and hatch in five to seven weeks, with the hatchlings left to fend for themselves.

What is most intriguing about these lizards is their ability to change color from bright lime green to dark brown, and while often called ‘American chameleons’, they are not true chameleons.  Their ability to change color is a result of three layers of pigment cells or chromatophores.  The first is the xanthophores which is responsible for yellow pigmentation, the second is cyanophores responsible for blue pigmentation, and the third is melanophores responsible for brown and black pigmentation.

Male Green Anole, brown color form

If one of the chromatophores is lacking due to genetics, color mutations can form, but are extremely rare in the wild. Blue-phased green anoles lack xanthophores, and yellow-phased green anoles lack cyanophores.  These color exceptions rarely live long, as they don’t provide the camouflage the green color does, which is highly useful in hiding from predators and hunting down prey.

Several factors contribute to the anole changing its color, including its mood, stress level, activity level, and even social signals such as displaying dominance.  Although claimed, evidence does not support color change due to camouflage or a response to background color, and it is even less clear if the color change is in response to temperature.  When stressed, during a fight for example, the skin behind their eyes may turn black and form postocular spots that resemble a small black mask.  

Regardless of the reason, no other lizard species in Texas is capable of such extensive color change.  With populations existing in even the largest of cities, these color changers are a fascinating part of our suburban landscape! 

Hummingbird Homecoming

 

Hummingbird feeders are busy during spring migration!

Early spring marks the beginning of several natural events, and one of the most welcome is the return of hummingbirds to central Texas.  While the number of hummingbirds migrating north in the spring is only about half of those migrating north in the fall (as the fall migration includes all immature birds that hatched in the summer as well as surviving adults), spring migration for these tiny birds is nonetheless an incredible feat.

Most scientists believe that the lengthening of daylight hours triggers the journey north, and evidence exists that hummingbirds follow a different route in the spring versus the fall.  While they follow the Texas coast south in the fall, presumably to avoid hurricanes in the Gulf of Mexico, in the spring they travel north hundreds of miles non-stop directly over the gulf’s calmer waters. 

Hummingbird feeders, filled with a clear solution (no red dye) of one-part white table sugar to four-parts water, should be placed out in early March.  Records show that the migrating hummers start arriving in our area at that time.  While these migrants can include more northern species that are just passing through, they mainly include the arrival of species that breed in our area, such as the Black-chinned Hummingbird (Archilochus alexandri) and the Ruby-throated Hummingbird (Archilochus colubris).

Black-chinned Hummingbird, male

Measuring a mere three and one-half inches long with a three and three-quarter-inch wing span, the Black-chinned hummingbird weighs only three to three and one-half grams, which is about equivalent to the weight of a dime plus a dollar bill. The male is dull metallic green above, gray below, black on the chin and upper throat, with an iridescent violet lower throat known as a gorget (pronounced gore-jet). The female lacks the characteristic coloring on the chin, upper throat, and lower throat.  Ruby-throated hummingbirds are also only about three and one-half inches long with the adult male having a black upper chin and ruby-red gorget, and they are a more eastern species with Austin being the westernmost border of their range. 

Ruby-throated Hummingbird, male

Like all hummingbirds, nectar serves as a main food source, fueling the tiny bird’s extreme metabolism.  These hummingbirds feed on several species of blooming plants, most notably native penstemons, agaves, salvias, sages, and honeysuckles.  While artificial feeders supplement their diet, they also prey on insects and spiders, particularly during nesting season, which gives them the dietary fat and protein necessary to breed.

The hummingbird’s unique skeletal structure allows them to fly forwards, backwards, sideways, and even on their backs!  This requires a wingbeat frequency of about 50 beats per second, and massive muscles that make up a third of their tiny body weight.  While the males perform an elaborate flight display during courtship, no pair bond is formed between the males and females.  Females build the tiny nest (out of spider webs, mosses, and various plant fibers), incubate the eggs, and raise the young, while the males are feeding and off chasing other females.  This is unusual among birds as a whole, since this class of animals exhibits the greatest amount of monogamy among vertebrates (animals with a backbone or spinal column).

Rufous Hummingbird. male

While most hummingbird species have moved out of our area by late October, be sure to leave a feeder out for stragglers and northern species that may spend the winter in your yard.  The most common overwintering species is the Rufous Hummingbird (Selasphorus rufus), but you can sometimes get a wayward winter visitor such as a Broad-billed Hummingbird (Cynanthus latirostris), a rare species in our area that arrived on our back porch feeder on September 11, 2021 and is still with us!

Broad-billed Hummingbird, male

Coexisting with Coyotes

One surprising fact about coyotes are that they are adept swimmers!

Intelligent, adaptable, and opportunistic, coyotes (Canis latrans) are generally misunderstood and are the one animal most often persecuted by humans.  As clever omnivores that also have a keen sense of hearing, sight, and smell, one can easily see how many myths and untruths have been associated with this species.

Contrary to popular belief, there have been no coyote attacks on humans in the city of Austin’s history.  Coyotes live in smaller family groups than wolves, and most often hunt solo, searching for small prey such as rodents.  They don’t generally breed with domestic dogs, and seeing them out in the daytime does not mean they are rabid or diseased.

Lanky and leaner than most dogs, mature coyotes weigh between 25 to 35 pounds, and have a territory size that can range from 0.25 miles (if rich in resources) to 40 miles (if poor in resources).  They are native animals that traditionally depended on habitat with lots of vegetation and food sources such as squirrels and rabbits.  However, with few predators and the rapid destroying of habitat through urban sprawl, coyotes are adapting, shifting, and as a result are more often seen and heard by humans.

A coyote's territory can range from a quarter mile to 40 miles.

Socially flexible animals, the behavior of coyotes and their activities change with the seasons and their circumstances. While they are typically most active at dawn and dusk, they can also be normally active day or night, and their activity is often timed to their life events.  From January to March they search for mates, from April to June the females give birth to 5 to 7 pups, from July to September they actively feed their growing pups, and from October to December the juveniles leave their dens and disperse in search of their own territory.

While frequently but not always seen, coyotes also leave telltale signs of their presence.  Their tracks often show two front nails, and there is more space between the paw pads, often forming an ‘X’.  Dog tracks, including the native gray fox, may or may not show nails, and exhibit less space between the paw pads, often forming an ‘H’.  The scat or droppings of coyotes is tubular, 0.4 to 1.4 inches in diameter, and 5 to 13 inches long with tapered ends.

The space between paw pads is different on a coyote (left) versus a gray fox (right).

Historically, coyotes have avoided competing with wolves, until wolves were hunted out (extirpated).  Both species were originally confined to the prairies of central North America, and while both wolves and coyotes were aggressively hunted, wolves were extirpated but coyotes thrived.  While the cause for this dynamic is somewhat complicated, the main factor for the success of coyotes is what happens when a family pack is disrupted.  Coyotes overcompensate for a population reduction, and a lone coyote can fill a void in a pack in as little as 2 to 3 weeks.  If alpha males or females are killed, other pairs quickly form, reproduce, and litter size can actually increase up to 16 pups.  In other words, coyotes have developed a biological response to make up for pack losses.

Coyotes have golden eyes and their coats range from dark gray to buff-colored.

Past attempts to control coyote populations have proved useless, and many methods are now illegal in the city of Austin, including traps, snares, and holds, which are inhumane and indiscriminate.  Even relocation of coyotes is illegal, because they can be a vector species for rabies, and relocating places them in unfamiliar territory.  

What we can do to coexist with coyotes is to learn to share space with them, but not time.  Non-lethal management tools that are ecology-based can successfully balance the humane treatment of wildlife with public safety concerns. Our behavior shapes coyote behavior, so doing simple things can minimize our interactions with them.  Coyotes are naturally afraid of people and their presence alone is no cause for concern. Keep your garbage and recycling cans inside and secure until the morning of pickup, close off crawlspaces under porches and decks, feed your pets indoors and keep them inside at night, and simply use noise to scare them away.

Coyotes are lanky and leaner than most dogs.

Remember that coyotes contribute beneficial aspects to our ecosystem by keeping prey species in check, and many scavenger animals, such as foxes and vultures, benefit from coyote predation on these prey species through increased food availability in the form of leftover carcasses.  And finally, like all wild animals, coyotes have a right to inhabit our wild places, including the preserves and open spaces that border our urban and suburban homes.  If you respect their right to exist, you may well be rewarded with a familial chorus of howls on a moonlight night!

Magical Migrant

Typical hummingbirds in our area include Black-chinned and Ruby-throated.

Known for their diminutive size, long thin bills, and amazing agility in flight, hummingbirds are in the order Apodiformes, meaning ‘unfooted birds’, as they have characteristically tiny feet and are unable to walk on the ground. They are in the avian family Trochilidae, often described as a group of more than 300 species of small, often brilliantly colored hummingbirds.  

While we frequently have Black-chinned and Ruby-throated Hummingbirds here during the warmer months, we also generally expect to have a Rufous Hummingbird spend the winter in our yard.  As such, we are used to keeping a feeder up all year round, but imagine our surprise when a male Broad-billed Hummingbird (Cynanthus latirostris) showed up at our feeder on September 11th!

The male Broad-billed Hummingbird at our back porch feeder.

Most of the Broad-bill’s range lies in Mexico, but it normally spends the breeding season in the mountains of extreme southeast Arizona and southwest New Mexico, where it prefers semi-shaded stream canyons and riparian areas with sycamores, cottonwoods, and willows.  They are short-distance migrants, and their winter range is typically entirely within Mexico.  Very few remain in the U.S. in winter, usually very near the Mexican Border, so to find one in Central Texas is a rare treat!

The brilliantly beautiful male Broad-billed Hummingbird!

Broad-bills are a rather small hummingbird with a long, straight bill and a center tail notch.  The male’s vivid red bill, rich emerald green body, and glittering sapphire blue throat (also called a gorget) is unmistakable!  Females are golden-green above and pale gray below, with a white line behind the eye.  When courting the female, the male hovers about a foot from the female and makes a flight display that is likened to a precise swing of a hypnotist’s pocket watch.  

The male Broad-billed Hummingbird perches in our Escarpment Black Cherry
in between trips to the feeder.

The female typically chooses a nest site about three feet off the ground in a downward-hanging tree branch or shrub. They weave 1-inch tall, 0.75-inch wide cups of bark strips, grasses, and leaves held together with spider silk that appear similar to clumps of vegetation deposited in branches during periods of high water, offering them a degree of natural camouflage.  After laying a clutch of 2 to 3 white eggs, the female incubates them and raises the young alone.

In the warmer months these hummers visit flower gardens but rely on sugar water feeders in winter when blooms are not readily available.  They consume more than 1.5 times their body weight in nectar each day, and often travel long distances between nectar sources.  They feed most often in the morning and late afternoon, which is when flowers produce the most nectar. Broad-bills can also capture tiny insects by gleaning them from plants and flycatching.  As small as they are, they often join others birds in mobbing owls perched during the day, to reinforce to young ones what predators look like or to help drive potential predators away.

There are 5 or 6 similar subspecies of Broad-bills in Mexico, but only the subspecies magicus is known to occur in the U.S.  Climate change has already begun to reshape the range of this hummer, although scientists believe that the vulnerability of this species will remain fairly stable overall.  It has been estimated that for its current range, about 16% has already been lost in the mountains of Mexico, 85% is maintained, and 35% is gained by expanding further north into Arizona, New Mexico, and West Texas.  Whatever the outcome, we welcome this magical migrant, and hope that he spends the entire winter with us!

Leave the Leaves!

Fallen leaves are not 'litter', but are food and shelter for many forms of wildlife.

This time of year, as the days shorten and leaves begin to fall, we can’t seem to help wanting to tidy up our yards and gardens by constantly mowing, blowing, and edging.  However, one of the most valuable things you can do to support pollinators and other beneficial species is to provide them with winter cover in the form of fallen leaves and dead plant material.

The Texas Alligator Lizard breeds in October or November, with females delaying egg
development during hibernation, laying their eggs in leaf litter beginning in February.

Leaves on the ground are not litter, which is unfortunately how most people see them.  Rather, they are food and shelter for many species of bees, beetles, butterflies, moths and other native creatures.  They are also habitat for beneficial snails, spiders, worms, millipedes, mites, and other small species that support the larger species such as birds and mammals that use them for food.

The larva or caterpillar of the Dusky-blue Groundstreak butterfly feeds on decaying leaves.

The vast majority of butterfly and moth species overwinter in the form of an egg, caterpillar, chrysalis, cocoon, or adult.  Some tuck themselves into a pile of leaves for protection from predators or the cold.  Others lay their eggs on fallen oak leaves, which becomes their first meal when they hatch in the spring.  Cocoons and chrysalises are often disguised with dried leaves, keeping them safe by helping to blend in and avoid predation.  Some species of lizard lay their eggs in fallen leaves, and many species of native bees and Sphinx moth larvae burrow into shallow soil for the winter, each attempting to survive the colder months covered in a protective blanket of leaves. 

The pupa (or immature inactive form between larva and adult)
of several species of Sphinx Moths, like this Virginia Creeper Sphinx,  
spend the winter a few inches under the soil, protected by a blanket of leaves. 

So how do you maintain your property while leaving the leaves?  First, if you must keep your lawn free of leaves, use a manual rake (it’s good exercise, too) and make a leaf pile in a corner of your yard or pile them up around your trees, shrubs, and perennials.  Don’t shred the leaves but keep them whole, let the leaf pile break down naturally, and leave the leaves that have already fallen in your beds and yard edges.  This free mulch provides you with valuable organic matter, builds up healthy soil, insulates tender roots, retains moisture, and helps to keep weeds at bay.   You can always decide to remove the leaves in the spring, once you wait late enough in the season so as not to destroy any overwintering species.

An adult Snowberry Clearwing Moth emerges from the leaf-covered ground in spring. 

And if the human side of things is more of a motivator for you, consider that the U.S. Environmental Agency has reported that mowers, edgers, and blowers used to remove leaves emit 27 million tons of air pollutants each year, not to mention the noise pollution that they create.  So do consider leaving the leaves this year, it’ll be less work for you and much better for the wildlife!

The Xerces Society encourages everyone to 
Leave the Leaves!

Madrone Mysteries

 

Texas Madrone

A striking small tree, to 30 feet, the Texas Madrone (Arbutus xalapensis) occurs in protected canyons and mountain slopes of Big Bend, but its range extends eastward to the Edwards Plateau in Travis County.  It is a rare native tree, but can be locally common in the right habitat, preferring grasslands and open oak-juniper woodlands on rocky limestone slopes. Its simple, pointed oval, leathery leaves, 2 to 5 inches long, are evergreen and medium green on top and lighter beneath.  In spring, clusters of small, fragrant, bell-shaped white flowers appear above the leaves, developing into bright red-orange fruits in late fall.  These fruits are relished by many species of birds and mammals and are reported to be edible by humans.

Texas Madrone flower cluster

One of the first mysteries of the Texas Madrone is its bark.  Bone-white and smooth when young, with age it becomes scaly and turns to shades of pink, red, and brown. This older bark peels away in patches and strips, revealing a smooth reddish bark underneath, and gives the tree some of its more colorful, old colloquial names such as Lady’s Leg and Naked Indian. But why does the bark exfoliate?  The most commonly accepted theory is that it is an evolutionary development to rid the tree of lichens and parasites such as wood boring insects, preventing their buildup and reducing the chance of disease.

Peeling Texas Madrone bark

Ashe Juniper nurse tree
protecting a young Texas Madrone

While it is one of the most interesting and beautiful native trees of Texas, another mystery of the Texas Madrone is that it is extremely temperamental to grow.  Its propagation requirements are complex, and it is very difficult to successfully transplant from the wild.  Madrones have a fine root system that is easily damaged, and even slight root damage is usually fatal to the tree.  Additionally, new seedlings require the protection of a ‘nurse tree’ to become established.  A nurse tree is a larger, faster-growing tree that safeguards the seedling while it gets established by providing shade, shelter from the wind, and protection from grazing animals.  For the Texas Madrone, its nurse tree is most often the native Ashe Juniper (Juniperus asheii). Adding to its temperamental nature, this tree is slow-growing, taking more than a century to attain a fully mature height.

Texas Madrone fruit

Texas Madrone trees flower from late February to early March, while their fruits don’t mature until late November to late February.  Like several species in the genus Arbutus, the fruits begin to form in mid-spring but fruit development is delayed for several months so that the next spring’s new flowers begin to appear while the previous year’s fruits are ripening.  This timing delay results in a short period of time when both fruit and flower can be simultaneously present on a tree, yet another intriguing characteristic of the mysterious Texas Madrone!

Hoppin' Orthoptera

Grasshopper nymphs are often mini versions of the adults

Take a walk through a meadow on a late summer or early fall day, and you’ll no doubt encounter members of the insect order Orthoptera: grasshoppers, crickets, and katydids.  While their Greek name translates to ‘straight wings’, these insects are better known for their jumping ability and powerful hind legs that can propel them to 20 times their body length. 

Abundant, large, colorful, and often noisy, orthopterans are unlike other insects in that they undergo an incomplete or gradual metamorphosis.  Their simple lifecycle consists of an egg, nymph, and adult, where the nymphs look similar to adults, but lack completely developed wings.  Eggs typically hatch in the spring, nymphs develop through the summer, adults mate and reproduce in late summer and fall, with winter passing in the egg stage.  They have three basic body parts: the head, which contains sensory parts such as antennae, eyes, and mouthparts; the thorax, which contains the legs and wings required for movement; and the abdomen, which bears the digestive and reproductive organs.

The use of sound is crucial in courtship, with each species having its own distinct song.  Males attract mates through stridulation, or producing sounds by rubbing the upper and lower wings or the hind leg and wing together creating a vibration that is species-specific.  The auditory organs for orthopterans are not located on their heads, however, but on the abdomen for grasshoppers and the front legs of crickets and katydids.

Differential Grasshopper

Common throughout Texas is the Differential Grasshopper (Melanoplus differentialis), which is brown to olive-green and yellow and up to 1.8 inches long, with black herringbone markings on its legs.  It feeds on both grasses and broadleaf plants, although it prefers the latter, and is often found in areas of lush vegetation. Both nymphs and adults tend to aggregate together, and the adults are found from July to October.

Obscure Bird Grasshopper

Also found thoughout Texas is the Obscure Bird Grasshopper (Schistocerca obscura).  This large grasshopper, to 2.5 inches long, has olive-green forewings and typically a pale yellow-green dorsal stripe from the front of the head to the wing tips. While females can lack this stripe, both sexes have blackish-purple tibia with yellow, black-tipped spines.  This species prefers fields and open woodlands, and can sometimes feed on flowers and shrubs.

Green-striped Grasshopper

The Green-striped Grasshopper (Chortophaga viridifasciata) is found everywhere in Texas except for the southernmost portion of the Trans-Pecos.  Up to 1.5 inches long, it has both a green form (usually females) and a brown form (usually males). Between forms, the main difference is the coloring of the head, thorax, and outer face of the hind femora, with the abdomen always being reddish-brown. This grasshopper prefers wet areas with short grasses on which to feed.    

Narrow-winged Tree Cricket

More often heard than seen, Tree crickets (Oecanthus sp.) are whitish to light green, with long antennae and slender bodies.  In late summer from dusk into the evening hours, the males begin to chirp, with the rate of the chirp correlating to the outside temperature.  If you count how many chirps you hear in 15 seconds and add that to 40, you’ll come surprisingly close to the actual air temperature in degrees Fahrenheit.  

Field Cricket

Field crickets (Gryllus sp.) are dark brown to black, about 1 inch long, live in cool, dark areas, and normally emit high-pitched, continuous calls.  Those that live in caves are dark brown, have well-developed hind legs, and exhibit a hunchbacked appearance.

Fork-tailed Bush Katydid

The antennae of katydids are hair-like and at least as long as the body, superbly represented by the Fork-tailed Bush Katydid (Scudderia furcata).  This all-green katydid is often found in weedy fields, thickets, forest edges, and along roadsides. Up to 2.2 inches long, the first generation matures in late spring and the second in early fall.  Interestingly, the overall size of the adults varies and is directly related to how fast they must mature in order to fully use the growing season to produce the maximum number of generations.

Often, what you can’t identify by sight during the day becomes clear when it sings, calls, buzzes, or chirps at night.  Immerse yourself in the nighttime soundscape, and hear your way to discovery!