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!

Roving Ringtails

Raccoon or Ringtail?

The common but elusive Ringtail or Ringtail Cat (Bassariscus astutus) is not a cat at all, but a member of the Procyonidae Family and a close relative of the Northern Raccoon.  The origins of its scientific name comes from bassar or ‘fox’, isc or ‘little’, and astute or ‘cunning’. In Texas, it is found mostly in the Trans-Pecos, the Edwards Plateau, and the Cross Timbers regions.   

An adult Ringtail on our back porch railing.

While ringtails are cat-sized mammals, their face is fox-like with a pointed snout, their body is elongated, and their tail resembles a raccoon.  The ears are large, and their big, dark eyes are each surrounded by a patch of light-colored fur.  The fur on their body is buff to brown-colored above and whitish below, with a spectacularly bushy, ringed tail.  This tail is often longer than their body, and is marked by a series of 14 to 16 alternating black and white rings (black rings incomplete on the underside) with a black tip.  

Close-up of the face of a Ringtail.

Mainly nocturnal but sometimes seen at dawn and dusk (crepuscular), ringtails are roving, solitary mammals that come together only to mate.  Their breeding season starts in late February and continues to mid-April, and females are in heat for only one 24-hour period during this time.  In early May to mid-June 2 to 4 cubs are born fuzzy, white-haired, and with a tail that is not yet colored with the distinctive black and white bands.  The cubs open their eyes at one month, and at four months begin hunting for rodents, insects, lizards, birds, and berries.  Ringtails are quite vocal, especially the young, and will make a variety of sounds including squeaks, chatters, grunts, growls, and hisses, with the typical call being a loud, plaintive bark.  In the wild, ringtails live an average of seven years. 

This Ringtail is eating sunflower seed that has fallen out of our bird feeders.

Ringtails can be found in our oak-juniper woodlands that have rocky areas associated with water, including riparian canyons and caves, limestone cliffs, and sometimes in man-made structures like mine shafts.  They can den in tree hollows, rock crevices, other animals’ abandoned burrows, and even seldom-used spaces in buildings.  They roam frequently, rarely spending more than three straight nights in one den.  Interestingly, the ankle joint of the Ringtail is very flexible and is able to rotate over 180 degrees, which makes them very agile climbers.  By pressing their feet against one wall and their back against the opposite wall, or by pressing both right feet against one wall and both left feet against the opposite wall, they are able to ‘stem’ or ascend/descend narrow passageways and wide cracks in the rock.  Their strong tail can provide balance for negotiating narrow ledges and limbs, and even allows them to reverse direction by performing a cartwheel!       

Getting access to our bird bath is an easy feat for the agile Ringtail!

Ringtails have many other common names, including Miner’s Cat, as they were often kept by miners and settlers as pets, to keep their cabin free of mice.  A hole was cut in a small box that was placed near a stove or fireplace, which acted as a dark, warm place for them to sleep during the day, and they returned the favor at night, hunting mice and keeping them and other rodents at bay.  In the native language of the Nahuatl Indians of Mexico, ringtails were called cacomistle, which is derived from the word tlahcomiztli meaning ‘half mountain lion.’  Whatever you call them, consider yourself lucky should you spot one of these beautiful, timid, and rarely seen nocturnal mammals!  

Requisite Night

 

Light pollution is nearly non-existent in Big Bend,
allowing for spectacular star-filled night skies.

Most environmentally-minded individuals recognize the more talked about threats to our native wildlife, such as habitat fragmentation/loss, invasive species, and climate change, but not as many are aware of the dangers posed by light pollution. Up until the mid-1800s, humans and animals lived under night skies solely lit by the moon. Electric outdoor lighting became common in the early 20th century, but its use spread quickly, and the global extent of modern light pollution became clear.  

By 2016, it was possible to measure nocturnal artificial light with the advent of a comprehensive global satellite measurement system. Researchers found that more than 80% of the world’s population lived under light-polluted night skies, or skies where the glow of artificial light is significant enough that the stars disappear from view.  In the US and Europe, it was found that 99% of residents live under light-polluted skies.

Light pollution exposes animals to many dangers, including predators, starvation, exhaustion, and disorientation. Artificial light, like roads and fences, can create barriers that fragment habitat.  Slow-flying bats avoid feeding in or passing through illuminated areas for fear of predators such as owls and other birds of prey. Artificial light near their roosts can also delay their emergence at dusk when their insect prey is most abundant.  If they never leave their roost since it always appears to be light, they can even starve to death.  

Artificial nocturnal light can also lure animals in and lead to their destruction.  Many species of migratory songbirds are attracted to brightly lit structures at night, circling them, sometimes colliding into them, or becoming disoriented enough to lead to a depletion their energy stores which ends in exhaustion and the inability to complete their journey.  In some bird species, artificial light at night interferes with their ability to use natural polarized light from the sky to calibrate their internal compass.

Artificial light at night attracts insects, like this Luna Moth, 
and can disrupt normal behavior patterns.

Light pollution is also one of the many factors contributing to the rapid decline of insect populations.  Moths and other nocturnal insects orient themselves by moonlight, and this instinctual tendency is interrupted by artificial night light, luring them in to fly incessantly around a bright light, causing exhaustion, exposure to predators, and the potential to miss courtship cues from mates.  This is especially true for fireflies, as artificial night light can cause them to alter or cease their mating flashes.  Studies have also shown that light pollution can harm diurnal insects like monarchs, who flit and flutter all night when exposed to excessive light when they should be resting, and causing them to be disoriented from their migration route.

Light pollution facts and some easy solutions.

Unlike other environmental threats to wildlife, simple solutions to artificial nocturnal light exist.  The best solution is to have no nocturnal lighting other than natural conditions. If a light at night is truly needed, the amount that spills into wildlife habitat can be reduced through dimming, downward shielding, or switching to motion-activated lights. Studies are also showing that lights in the warmer color tones are less disruptive than bright white lights.

Travis Audubon promotes the Lights Out Initiative for Austin.

Austin is one of several cities across the US that participates in the migratory bird friendly Lights Out Initiative, which asks residents to turn out all non-essential lights from 11pm to 6am every night during spring migration (March 1 – June 15) and fall migration (August 15 – November 30).  This is one of many ways we can prevent light pollution from overpowering our native wildlife. Turn out your lights when they are not needed, and welcome the requisite night!

Irruption Disruption

Pine Siskins often feed in groups or flocks

While many northern species of birds fly south through central Texas during fall migration, some species go no further, and spend their winters in the area. Our generally mild winters and higher availability of food sources are the reasons they stay, fueling themselves in the cooler months as they prepare for northward migration in the spring.  

This cycle is not always predictable, however, as there are a few overwintering bird species that are nearly absent in some years, and overly abundant in other years.  One such species is the Pine Siskin (Spinus pinus), a small finch-sized, seed-eating bird with a sharp pointed bill, short notched tail, and streaky brown overall with subtle yellow edging on the wings and tail.  They flash yellow wing markings as they flutter while feeding or burst into flight, and usually occur in fairly large, gregarious flocks.  Their wheezy twitters are a dead giveaway, and they will stay all winter near a dependable food source.  

Pine Siskin showing the yellow edging on wings and tail

Pine Siskins range widely and erratically across North America every winter in response to seed crops, and flocks may monopolize your feeders one winter and be completely missing the next. In the winters when Pine Siskins are abundant, the phenomenon is referred to as an irruption.  In the bird world, irruptions, broadly defined as sudden changes in population density, refer to the movement of northern-wintering bird species to the south in years of low food availability. However, some recent bird banding studies suggest that some pine siskins fly west to east while others fly north to south in search of winter food.

While fairly common, the overall population of Pine Siskins is difficult to estimate due to their unpredictable seasonal movements.  However, this species is considered to be in steep decline, with an estimated 69% decline in numbers from 1966 to 2019.  Natural threats include predation by outdoor domestic cats, squirrels, hawks, and jays.  Man-made threats include pesticides, mineral deposits from salts used to melt ice and snow, outbreaks of salmonella from unsanitary feeders, and forest clearing.

Pine Siskins will quickly empty your feeders!

Winter flocks of Pine Siskins can be aggressive around food sources, often trying to disrupt and challenge feeding competitors by lowering their heads and spreading their wings and tail. They may even lunge toward and pick fights with other seed-eating birds such as Lesser Goldfinches and House Finches. Keep an eye on your feeders this winter and you just may witness this irruption disruption, when flocks of these birds can eat you out of house and home!

Breeding Beauties

White-eyed Vireo nest, a sign of spring

As the fickle winds of  spring come in from  the south, they usher in several  species of birds  that spend the warmer months  in Central Texas.  Most of these species overwinter in Mexico, Central America, or South America, and their arrival in  our  area  signals  the start of the  breeding season.  Most notable  are the  Summer Tanager,  White-eyed Vireo,  Western Kingbird, and Scissor-tailed Flycatcher.

Summer Tanagers (Piranga rubra) are medium-sized, chunky songbirds with big bodies, large heads, and thick, pale, blunt-tipped bills.  Mature males are the only birds in North America that are completely red.  The female and immature males are bright yellow-green, which makes them harder to spot in the forest canopy. These birds prefer to stay fairly high in the trees, often in willows, cottonwoods, and mesquite along creeks and streams.  They prefer to sit still then fly out to catch insects in midair.  They are especially fond of bees and wasps, beating them against a branch once they are caught, but they may also forage on berries and fruits near their forest habitat.  Males have a sweet, whistling song, much like an American Robin.

Summer Tanager, male

Like most vireos, White-eyed Vireos (Vireo griseus) are small songbirds with compact bodies and thick, slightly hooked bills.  They have yellow spectacles around their white eyes, yellow-washed sides, gray head, white throat, and two white wingbars.  They prefer areas that are scrubby and thick with vines and other vegetation, staying hidden in the understory where they glean caterpillars and other insects. Their song is distinctive, rapid and harsh, sounding like ‘Spit. And see if I care. Spit.’ While only the males sing on their breeding grounds, both males and females have been found to sing on their wintering grounds.  They bathe by rubbing their bodies against dewy foliage in the early morning, or by quickly dipping their backsides in a pool of water.

White-eyed Vireo

Oddly often found in parking lots with Live Oak trees, Western Kingbirds (Tyrannus verticalis) are fairly large flycatchers with gray heads, broad shoulders, whitish chest, lemon yellow bellies, heavy straight black bills, and medium-length black tails with white outer tail feathers.  They prefer open habitats, often perching on power lines, fences, and in trees, waiting to hawk insects from the air.  In fact, their breeding range has been expanding as an unplanned result of humans planting trees and installing utility poles in open areas.  Their territory defenses include lots of wing-fluttering and a long series of squeaky, bubbling calls.  Paired males and females work together to defend their territory, which shrinks as the breeding season progresses.

Western Kingbird

Few birds are as graceful to watch as Scissor-tailed Flycatchers (Tyrannus fortificatus).  These elegant, slender birds are gray overall with salmon-pink flanks and underbellies, stout black bills, blackish wings, and long, forked tails they use to sharply twist and turn midair to catch insects.  Interestingly, Scissor-tails are known to use many human-made products in their nests, including pieces of cloth, paper, string, and even carpet fuzz and cigarette filters.  These items can account for up to 30% of the weight of the nests.  In late summer and early fall, these flycatchers gather to form large, bickering flocks and migrate together back to their wintering grounds.

Scissor-tailed Flycatcher

Scissor-tailed Flycatcher, showing its' namesake tail

Cool As A Cucumber

 

Another common name for Cucumber Weed is Pennsylvania Pellitory

In the middle of our Central Texas winter, one does not normally think of plants emerging from their cold weather slumber.  But one plant starts to appears in the cooler days of late fall through early spring, and it is appropriately named Cucumber Weed (Parietaria pensylvanica).

While native throughout much of the US and into Mexico, Cucumber Weed, also called Pennsylvania Pellitory, is generally considered an urban weed.  It grows in light shade with moist to slightly dry soil, mostly in disturbed areas along the sides of buildings, in suburban yards and gardens, and in woods and thickets. In fact, its’ genus name is derived from the Latin paries which means ‘wall’, which is where the plant likes to grow, presumably due to its affinity for alkaline soils. It is a member of the nettle family, but lacks the stinging hairs of most nettles and is considered unarmed.

The typical upright habit of Cucumber Weed

Cucumber Weed is 0.5 to 1.5 feet tall, typically erect and unbranched, and has a green, 4-angled, hairy stem.  Its alternate, simple, thin green leaves are lance-shaped, up to 3.5 inches long and 0.75 inches wide with smooth margins, although they are smaller on younger plants.  

The leaves of Cucumber Weed are hairy and have smooth margins

Small clusters of bracts and flowers appear at the axils of the middle and upper leaves.  Each tiny, almost indistinct, greenish-white flower is surrounded by longer green bracts, and the bloom period lasts from April to November. Flowers can be staminate (male), pistillate (female), or perfect (male & female), and these different flowers kinds of flowers can appear together in the same cluster. Cross-pollination occurs by the wind, and the plant reproduces by reseeding itself.  It frequently forms colonies and while it is a persistent plant, it is not aggressive like most invasive species.

Cucumber Weed's tiny flowers are surrounded by long green bracts

Often considered a medicinal herb for its diuretic ability reportedly used to help flush out kidney stones, Cucumber Weed is also high in potassium and edible, although caution must be taken as a small percentage of people may be allergic to it.  The early leaves of young seedlings offer the strongest cucumber taste, while leaves from older plants seem to lose some of their flavor.  Some use the raw leaves in salads or smoothies, or steamed and mixed with pasta. In an online database of indigenous plants of Mexico, Cucumber Weed is called Hierba del Rayo or ‘Lightning Herb’, as it was said that a poultice of this plant applied to your forehead overnight would relieve the chills, fevers, headache, and nosebleed resulting from a nearby lightning strike.

Red Admiral

Care should be taken not to completely remove Cucumber Weed from your yard or garden as it also has value to several types of wildlife.  It is a host plant for the Red Admiral Butterfly, whose caterpillars eat the soft leaves and create shelters from predators by tying up leaves at the end of a shoot or by folding over a larger leaf.  

Lincoln's Sparrow

Cucumber Weed is a source of seed for Lincoln’s Sparrows during fall migration, and there is evidence that White-tailed Deer like to browse the foliage.  Try to stay cool as a cucumber and resist the temptation to pull up Cucumber Weed, as this is one ‘weed’ that is useful to humans and wildlife alike! 

Birds and Berries

 

 A flock of over wintering Cedar Waxwings

Several species of birds overwinter in Texas during the colder months of the year, since food is typically more abundant here than in the northern parts of the country.  While many types of seed can provide nourishment when insects are not available, it is the berries that draw in large flocks of American Robins (Turdus migratorius) and Cedar Waxwings (Bombycilla cedrorum). 

American Robins are fairly large songbirds that are easily identified by a dark gray head, lighter gray back, yellow bill, and a rusty orange belly.  Throughout the fall and winter months they switch their diet from worms and insects to several types of berries, and often band together to form large flocks.  Look for them roosting in trees in moist woodland areas where berry-producing trees are shrubs are common, from November through mid-April.

American Robin

Cedar Waxwings are medium-sized songbirds with a sleek, silky look.  They are identified by a pale brown head with a crest that often lies flat, a narrow black mask outlined in white, a lemon-colored belly, and soft gray wings and tail. The tail is always tipped in bright yellow, and the wings have red waxy tips but they are not always easy to see. They also congregate in large flocks and are usually heard before seen, emitting a high-pitched trill as they fly about, from November through May.  They typically eat fruits year-round, depending on what is available.

Cedar Waxwing

In central Texas, overwintering American Robins eat berries from a variety of native plants, including Escarpment Black Cherry, Roughleaf Dogwood, Flameleaf Sumac, Ashe Juniper, Yaupon, Possumhaw, and Virginia Creeper.  In winter, Cedar Waxwings have a high preference for the berries of the Ashe Juniper, but will also eat the fruits of American Mistletoe, Texas Madrone, Roughleaf Dogwood, Yaupon, Possumhaw, and Coral Honeysuckle.

Ashe Juniper

It is important to note that these birds will also eat the berries of non-native, invasive plants such as Ligustrum species, Nandina, and Japanese Honeysuckle.  Since these unwelcome plants largely spread by bird droppings that contain the seeds of these fruits, replacing them with the native alternatives listed above is a responsible way to help safeguard against that spread.

Yaupon

From time to time, these birds can become intoxicated if they eat too much fruit that has fermented. Berries and other fruits can ferment in late fall and winter when frosts and freezes occur, which concentrates the sugar in the berries. When these cold periods are followed by warmer weather it accelerates the breakdown of the sugars into sugar alcohol, at a more potent level than might normally be present.  

Possumhaw

Like humans, drunken birds show signs of irregular movement and the inability to avoid obstacles, and some immature birds even risk the chance of death through alcohol poisoning.  Recent research shows, however, that birds such as Cedar Waxwings may have some natural protection against drunkenness due to their fairly large livers (for birds), as those livers can more effectively break down the alcohol to safely remove it from their bodies.

Each year, the numbers of American Robins and Cedar Waxwings present during a central Texas winter can fluctuate wildly.  In some years, when ample rains produce berries in copious amounts, these birds will appear in large flocks. But during drought years when berries are scarce, especially on junipers, these birds are found in much lower numbers.

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!

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!