Friday, June 27, 2014

Wood Storks Taken Off Endangered Species List And Return To The Great Trinity Forest

A Juvenile Wood Stork at Joppa Preserve on the evening of Juneteenth 2014, Dallas Texas. One of the most rare and special animals in Texas.
It was an early summer Thursday, June 26, 2014 to be exact that marked a significant moment for one of the most imperiled wading birds in the world, the Wood Stork. A mere thirty years ago, biologists said that by the year 2000 the Wood Stork would be extinct from the planet. It was on that Thursday, Sally Jewell, Secretary of the Interior announced the down listing of the Wood Stork from “endangered” to “threatened,” finding that the birds, which breed only in the Southeastern United States, no longer face imminent extinction.

A young Wood Stork stands alone in the Great Trinity Forest June 2014 taking a brief break from foraging the submerged bottom of a lake for food.
Wood Storks were protected in 1984 under the Endangered Species Act after the birds had declined from approximately 20,000 pairs in the late 1930s to 5,000 pairs in the late 1970s, largely due to draining and development of wetlands. After the Wood Stork was designated as endangered, work began to preserve and restore wetlands and protect nesting areas. According to the US Department of Fish and Wildlife the most recent three-year population average ranged from 7,086 pairs to 10,147, however, the five-year average of 10,000 nesting pairs identified in the recovery plan as the target for delisting had not been reached.

Wood Stork spreading wings with the imminent approach of a fast moving storm over the Great Trinity Forest, June 2014
The change in designation by the U.S. Fish and Wildlife Service marks an important step toward full recovery but will not reduce the species’ legal protection. Some believe political pressure by golf course corporations and homeowners associations pressured the move from endangered to threatened. The rigid enforcement protections for the birds and their habitat remain in place despite the change in designation.

About The Wood Stork Mycteria americana

Wood Stork Mycteria americana exhibiting the unique to the species feeding technique

Few Dallasites have ever heard of a Wood Stork. Only a handful of even experienced birders have even seen one.

Wood Storks (Mycteria americana) also called the Wood Ibis are large water birds that stand 4 feet tall and are the only stork in North America. They have wingspans as wide as 5 1/2 feet. They are mostly white, but have a black tail and many black feathers under their wings. Storks are related to ibises, herons and flamingos. Adults have no feathers on their head and neck, so the black skin underneath shows. This makes wood storks the only tall water birds with black, bald heads. Since they have no muscles attached to their voice box, they are very quiet birds.

Best Places In Dallas To See A Wood Stork
Trinity River Audubon Center

John Bunker Sands Wetland Center

 Both nature centers have sightings of Wood Storks off and on from the 4th of July till August. The Wood Storks move around between feeding and roosting zones so they are not round-the-clock residents on any given day. You can call ahead and check for sightings. Both locations have confirmed sightings in 2014.
Wood Stork and three Snowy Egrets working a nearly dried up Little Lemmon Lake under darkening skies of a thunderstorm, June 19, 2014
Faster than a hummingbird, the quick snaps of the beak are blurred even in high speed photos
Wood storks use the massive beak as their source of food gathering.  The feed in water no deeper than their beak and catch a variety of things in their bill which they then toss their head back and swallow.

This technique is known as “grope feeding”.  This because the stork does not use vision in food collection, but instead does everything by touch.

The reflex of the bill after it touches food is thought to be the fast of any reflex in the vertebrate world. When it feels a fish, the stork can snap its bill shut in as little as 20 milliseconds—an incredibly quick reaction time.

Video footage of the Juvenile Wood Stork at Little Lemmon Lake during a gathering thunderstorm and downbursts of wind

Their diet has been known to consist of fish, crayfish, salamanders, tadpoles, shrimp, frogs, insects and an occasional snake. Storks also use their feet to stir the bottom when collecting prey.  This technique startles the food from the vegetation into the beak. Some think that the water turbulence caused by this action simulates the water movement of a feeding frenzy, and can attract fish to become prey. 

Wood Stork with another catch, a small fish most likely one of the hardy species of Mosquito Fish that are found here

A Dry Spell And Habitat Loss For Wood Storks In The Great Trinity Forest
Seabreeze storms boiling up from the Gulf as seen from Miller's Switch in the sleepy community of Joppa, evening of June 23, 2014
Wood Stork in the Great Trinity Forest June 2014
The seabreeze fronts that start in the Gulf of Mexico push northward during the daylight hours. They track roughly up the Trinity River from the Gulf of Mexico to about Corsicana. If they are long lived fronts they can make it as far as the Dallas area with a pronounced gulf smelling breeze and cool humid laden air. Most evenings, like the photo above illustrate, the storms make it to Navarro or Ellis Counties.

Spring 2014 came in late, cold and dry for North Texas, third year in a row. Dry years stacked on top of one another start changing the look of things down here on the Trinity. Ponds and small lakes don't hold as much water or none at all. Those water bodies that do have some depth to them go dry in June rather than August.

The weather might be late but a few brave Wood Storks ventured into the Great Trinity Forest weeks ahead of years previous.

In years past, especially in 2011 and 2012 there were many overbanking events with the Trinity River that filled Little Lemmon and Lemmon Lake. These events created ideal habitat for Wood Storks which gathered in the hundreds seen here in 2012

And of course the African safari like backdrops of wild pigs wading across Lemmon Lake with well over 100 Wood Storks and hundreds of other wading birds in the lake:

Little Lemmon Lake going dry months earlier than normal, June 2014

The past half century has borne witness to dramatic changes in the quality and quantity of wildlife habitat. Throughout the United States, Mexico and South America, wetlands continue to be drained and filled, forests cut and fragmented, and grasslands developed for construction. Other less intrusive land use practices like golf courses have upset the natural balance as well.
Caterpillar D6R clearcutting a large swath of the Great Trinity Forest for the Trinity River Golf Course
From the article written by Bill Nichols and Rudolph Bush "Suhm and Rawlings pledged that the Great Trinity Forest will not be disturbed by the golf course development. The land for the course will be limited to the bare landfill property.  “They won’t be doing things in the forest. No taking down trees. They will be planting trees,” Suhm said."

One could take a guess as to whether or not those were sincere promises now.
Same spot a few days later as viewed from across the fence standing on the Trinity River Audubon Center property. Better wear your sunscreen if you plan on visiting the Byron Nelson when it moves here.
Many of these habitat changes from natural woodlands to managed groomed greenspace are not what they appear. While forest and woodland cover in some areas has actually increased, the quality of those habitats compared to the original woodlands may not be similar at all because of changes in vegetation composition and artificially abundant predator populations.
Wood Stork working for crawdads and small fish among the dilapidated pilings of a circa 1920s fishing pier in the Great Trinity Forest
Without some heavy tropical systems brewing in the Gulf this summer, the habitat for wading birds will be quite scant in the Great Trinity Forest. The moonscaped clearing of the Great Trinity Forest and landfill areas for the golf course will impact the wading bird habitat that use the pocket ponds in that area during the height of the summer months. Perhaps it will be a permanent change.

The rare places left inside the city limits of Dallas that attract such wildlife seem to be in real peril from planned development. These smallish ponds and drying beds are the real endangered species of note. Oh so rare and important to so many species of birds, the world over, who seek out the water here for habitat. It would be a tremendous loss to the city as a whole, we would all be poorer for it, if the planned development here impacted the wildlife in any way.

Where does a federally protected threatened species fit into the mix remains a cloudy picture.

Up A River Without A Paddle -- Tracking The Fascinating Inland Dispersal Of The Wood Stork
Eye to Eye with a Wood Stork not 15 feet away at Joppa Preserve June 2014. In the higher resolution version of this photo I can see myself in the eye reflection. Too many people rush for shots of wildlife. Patience pays off, in this case sitting among the high swamp grasses and mud, then letting the birds slowly march along foraging for food. Stalking or slow walking up to these birds never works. What does work is letting the wildlife decide what is comfortable. The result is a look into the bird few see. A slight turn of the head look but without the flighty facial expression of profound shock so many pictures often exhibit.
Wildlife, both fleet footed and on the fly, use the Trinity River as a main artery of travel from the parched uplands northwest of Fort Worth, clear to Trinity Bay on the Gulf of Mexico.

The Wood Stork that we see in Texas, moves inland after nesting along the Gulf of Mexico during the spring. The birds seek out shallow drying ponds and water bodies where concentrations of fish exist in great numbers. A reverse migration of sorts that when seen through human observed reports read like a ten mile march up the Trinity every day from May through July.
A Wood Stork mimic marches the gait of a Snowy Egret as a Tri-Colored Heron watches in the foreground
The easiest way to track movements of Wood Storks or any migratory bird species is to use Ebird, a google map based website which allows the user to search for specific species, locations, dates and years that birds have been spotted.

Wood Stork migration and dispersal has likely been this way for hundreds or thousands of years, a route implanted upon the DNA of the species who frequent the river. Wood Storks are most likely no exception to that process. Many of us humans were not born into the intimacy of our natural environs, using tools like Ebird gives us the ability to see the ebbs and flows of the natural world transformed into data we can understand.
As mentioned earlier, Wood Storks have a unique feeding technique and require higher fish concentrations than other wading birds. Optimal water conditions for the Wood Stork involve periods of flooding, during which prey (fish) populations increase, alternating with drier periods, during which receding water levels concentrate fish at higher densities coinciding with the stork's nesting season.

The Wood Stork, Bald Eagle and many other species of migratory birds owe their current existence in the United States to the determined, last-ditch efforts carried out under the legislative milestones of the Endangered Species Act. Attempting to pull species back from the brink of extinction can be an expensive and contentious proposition.

Even today, despite considerable conservation gains in the past few years, many challenges still threaten to drive species away from healthy populations, and onto the endangered species list. There are many cheap and smart ways to increase habitat for these type birds in the Great Trinity Forest with no impact on planned "World Class" amenities as they are called for the area. Money can buy a lot of things, almost anything, a Wood Stork and their free will to call this neck of the woods home is not one of them.

Wednesday, June 25, 2014

Swamp Hiking Beyond Big Spring In The Great Trinity Forest

The maze of wetlands, swamp and lush vegetation in the Great Trinity Forest within walking distance of Big Spring
Dawn on the longest day of the year lights the eastern sky well before 6am, the earliest of early sunrises. The solstice fell on a Saturday in 2014 a day chosen to venture into the large wetlands and swamps beyond Big Spring in the Great Trinity Forest. Most people avoid such areas full of high water, snakes and dense vegetation. A difficult hike and wade through some of the harshest topography in Dallas.

Jim Schutze who writes for the Dallas Observer referred to this area as "Nature Post-Apocalypto" in a 2012 article entitled A Bushwhacker's Guide To Dallas. A part of town that was left to be forgotten due to the high floods that came with every storm in the watershed.

Sean Fizgerald sitting next to the silver pipe structure visible from Big Spring which sits to the south. In the background is a bar gate leading to a Water Utilities ROW with swamp and wetlands beyond.

Diamondback Water Snake cruising the swamp
The goal for this hike was to push north from the relative serene nature of Big Spring and hike northwest through some great swamp country, under 175 and up into an area Tim Dalbey calls Bruton Bottoms. A mass of felled timber and ephemeral wetlands that make for some very tough going.

Getting there is a little bit of a trick from Big Spring. We needed to cross some private property owned by Father Richard Hill and his wife Paula Pemberton Hill. They were kind enough to grant us access across their property towards Bryan's Slough, Oak Creek and White Rock Creek. That land and many of the adjoining parcels were part of the larger Edward Case Pemberton farm that was purchased from Margaret Beeman Bryan, the widow of John Neely Bryan founder of Dallas.

One of the larger beaver impounded bodies of water in Dallas. A stunning view inside Loop 12 few have ever seen.

An emerging Swallowtail Butterfly preparing for first flight
It would blow away most long time Dallasites and natives to know that places like this not only still exist but the fact that they exist at all. Dallas as a city gave up on this land many decades ago.
Hibiscus taller than a man ringing wetlands in Dallas

 For the last forty years, the area fell into extreme neglect. The grid of old streets served as a favored illegal dump for cars, tires, shingles and the occasional human. During those forty some odd years of abandon, the outer areas of this bottom land began to heal. Trees slowly began to take root, old farmed areas went to seed, then weed, then tree.

Roosevelt Heights sits just a hair above three creek intersections on a small peninsula rise of land running north to south bisected by US 175. In the southern half, large wetlands sit on either side of the peninsula. In the last half decade these swamps have gone bone dry no later than mid June. The water height and impoundment is determined by rainfall and to a larger extent by beavers and their engineering of dams in the area.

A male Indigo Bunting making a territorial call from his perch in the early morning light of the Summer Solstice 2014. These birds fly from Central America to the Great Trinity Forest every spring to breed

Roosevelt Heights is named after President Franklin D Roosevelt and his New Deal programs that are believed to have spurred development of low income housing in this area. Reading up on the background I think most of the Roosevelt Heights area was developed in the post war boom of the 1940s at a time when Dallas saw an influx of skilled African American laborers from East Texas. The epic drought of the 1950s in Dallas allowed home construction in areas well within the 100 year flood plain. Unaware for years that their new homes were in peril when normal rain patterns returned.
Arrowhead plants in the foreground
Roosevelt Heights grew in the interim. A population of less than a thousand, three churches, two grocery stores, hair salons and a sundry store or two. It was a real community. That came to an abrupt
end in 1957 when Roosevelt Heights saw the first major sustained multi-day flood. The aerial photo(inset) shows the extent of the flooding that spring which inundated Roosevelt Heights and Rochester Park. In the photo, Second Avenue can be seen running lower left to upper right. Roosevelt Heights in the foreground and Rochester Park in the background left. Many of the refugees from this flood were forced to live in railroad boxcars until flooding subsided. Few moved permanently after this flood.

The 1960s brought flood after flood to Roosevelt Heights. The flooding was magnified by new levee construction upstream and urbanization of former farming lands.
A channelized branch of Oak Creek with a pronounced levee running on the west side. This levee was built between 1968-1972 to provide a degree of flood protection from smaller flooding events from the Second Avenue/175 intersection
The result was not a devastating flash flood but a backing up of flood water from the Trinity into the White Rock watershed. In the early 1970s, talk began of flood control improvements. Rochester Park was earmarked for a levee and Roosevelt Heights was bought out by the city. In the lower section of Roosevelt Park, the last homeowners around 1973. North of US 175, one homeowner, at last check, still resides today.

Masters of Construction and Engineering -- The Great Trinity Forest Beavers
Up close and personal with a beaver on June 21, 2014
The beaver pictured here came to check us out and see what we were up to. Friendly in every way, it approached within twenty feet or less of us and watched us with great interest. Perhaps it had never seen a human before and wondered what we were.
Beaver at a distance creating a bow wake as it approaches with great interest June 21, 2014
 Once among the most widely distributed mammals in North America, beavers were eliminated from much of their range in the late 1800s because of unregulated trapping. With a decline in the demand for beaver pelts, and with proper management, they became reestablished in much of their former range and are now common in many areas.  Beavers are found where their preferred foods are in good supply—along rivers, and in small streams, lakes, marshes, and even roadside ditches containing adequate year-round water flow.
One of many great beaver dams. Pictured is Master Naturalist Bill Holston admiring the construction of the dam
 In areas where deep, calm water is not available, beavers that have enough building material available will create ponds by building dams across creeks or other watercourses and impounding water.  Beavers dams create habitat for many other animals and plants of Texas. In winter, deer frequent beaver ponds to forage on shrubby plants that grow where beavers cut down trees for food or use to make their dams and lodges. Raccoons, and herons hunt frogs and other prey along the marshy edges of beaver ponds. Migratory waterbirds use beaver ponds as nesting areas and resting stops during migration. Ducks often nest on top of beaver lodges since they offer warmth and protection, especially when lodges are formed in the middle of a pond. The trees that die as a result of rising water levels attract insects, which in turn feed woodpeckers, whose holes later provide homes for other wildlife.
Flooded willows and water covered with cottonwood seed
Beavers have constructed large and complex sets of dams through the bottoms here, keeping much of it flooded through one of the driest spring seasons on record in Dallas.

Their tireless work has left large sections of the woods here submerged for most of the year, forming great habitat for ducks, wading birds, aquatic insects and fish. The water is quite clear and in some spots has a hard bottom suitable for careful wading.

A prime example of Great Trinity Forest sedge

Sedge grasses in large pockets like the one above provide critical wetland habitat for dragonflies, crawfish and in wet seasons fish. These sedge patches are often overlooked by many but perform a critical role in establishing biodiversity in the Great Trinity Forest.
A huge wetland forest area dominated by native hedge in the background and invasive Alligatorweed in the foreground
Adult White Ibis

Alligator weed Alternanthera philoxeroides is a perennial plant native to South America and often forms very dense stands or mats that make shoreline access difficult in the Great Trinity Forest.The water loving aquatic stems are hollow and can be single or branched. Leaves are opposite, long, elliptical or lance-shaped up about an inch wide and half a foot long with a prominent midrib. Often roots develop at leaf nodes. Soft, whitish hairs are found in the leaves. Single flowers are small (about 1/2 inch in diameter) white, fragrant clusters of 6 to 10 florets, borne on long branches (to 3 inches). The flowers resemble those of white clover. A single seed develops within the fruit.

Juvenile White Ibis fishing from a log in the Great Trinity Forest June 21, 2014
When alligator weed invades waterways it can reduce water flow and quality by preventing light penetration and oxygenation of the water. It can also reduce water bird and fish activity and cause the death of fish and native plants. Alligator weed mats create a favorable habitat for breeding mosquitoes. Alligator weed is also difficult to control and such is prohibited from owning.
Tri-Colored Heron sprinting through the shallow water for a mosquitofish in the Great Trinity Forest June 21, 2014

The Halberd Leaf Rosemallow -- A Texas Native
Wild hibiscus growing in the Great Trinity Forest
At first glance one would wonder how hibiscus could naturally grow in Dallas wetlands. The second question is who planted them? The answers are that they are native to North Texas, have always grown here and thrive naturally just as they have for centuries in this special swamp. These plants go by the name Halberd-Leaved Rose Mallow due to their distinctive shaped leaves that resemble a medieval battle axe sword called a halberd.

The Halberd Leaf Rosemallow is commonly known by its Latin name Hibiscus laevis. Sometimes it is also called soldier hibiscus. The "militaris," "soldier" and "halberd" parts of its various names allude to the similarity between the shape of its leaves and the lance end of a medieval pole-ax called a halberd. The leaves have pointed tips and a broad, deeply lobed base with a silhouette similar to a double-headed ax. Unlike many hibiscus family members, the Halberdleaf rosemallow has smooth leaves and stems.

A pollen laden bumblebee tries to wiggle out of a hibiscus flower

Each plant grows upright, reaching a height of 3 to 6 feet. Each five-petal blossom grows out of a leaf axil, the point at which a leaf joins the stem.

The harsh winter of 2014 had little effect on the hibiscus here that tower over eight feet in some cases

Hibiscus blooms emerge from the bottom to the tip of the stem. The Lady Bird Johnson Wildflower Center notes that the flowers may bloom from May to November, depending on the region. In the Great Trinity Forest they bloom only in the mornings from June through October. The blooms will stay open longer on cloudy or rainy days.

Many volunteer hours are now being put to good use in studying the flora and fauna of Big Spring and the immediate wateshed. Continuing the great hands on management plan developed by Billy Ray Pemberton plus the added knowledge of many experts will help keep the aesthetic of the place going for generations to come. It will also allow many of the plants that were traditionally mowed to flourish and bloom out for years to come. Big Spring has a number of  native hibiscus growing on the conservation and future landmark footprint. They should be blooming in the next several weeks.

The easy walk back towards the icon of the forest, the Histori Big Spring Bur Oak
 As we walked back to Big Spring, in the far echoing hollow we could hear the faint yell of Master Naturalist Jim Flood and Geoarcheologist Tim Dalbey who had been conducting a weekly plant census. Horse trading field notes, Jim Flood pointed out some unique specimens of plants he had gathered for further study. A couple days later, he reported that one of the plants had not been seen in Dallas County for a very long time and was originally first documented by none other than famed Botanist and La Reunion Colonist Julien Reverchon. An important find.

As we learn more about Big Spring, what makes the woods tick, how the swamp and wetlands connect with Big Spring as an ecosystem we can begin to paint a picture of how special this part of Dallas is and something that should be forever preserved and protected.

Tuesday, June 17, 2014

Scissor-tailed Flycatchers and Kingbirds In Texas Trinity River Corridor

Texas Bird of Paradise, the Scissor Tailed Flycatcher perched on an Arkansas Yucca surrounded by Prairie Coneflower and other native wildflowers in Dallas, Texas

The strong southerly winds of a Texas spring bring more than humidity up from the Gulf of Mexico. Riding the air currents north from as far away as the tropical rainforests of Central and South America are the flycatchers of the bird world.

The dripping wet blossoms of an native Arkansas Yucca just after an spring thunderstorm at McCommas Bluff Preserve, Dallas Texas, Spring 2014
Scissor-tailed Flycatcher at the Mockingbird-Westmoreland Bridge in the Trinity River Floodway, Dallas, Texas. Downtown Dallas and Victory Park can be seen in the distance
The flycatchers are fond of the open spaces and fence lines of the Trinity River. In the late Spring, June to be precise, the birds move into Dallas in great numbers setting up shop among high insect populations that dominate the fields here. The three most dominant species seen are the Scissor-Tailed Flycatcher, the Eastern Kingbird and Western Kingbird. The Trinity River Corridor serves as a great overlap for the Kingbird species with near equal amounts of both Eastern and Western species.

Scissor-Tailed Flycatcher Tyrannus forficatus
The Scissor-Tailed Flycatcher Tyrannus forficatus is known by other names as well... Scissortail, Texas Bird-of-Paradise and Swallow-Tailed Flycatcher.

From the appearance, it is obvious how the bird acquired its common names, but its former Latin name - Muscivora forficata, describes the bird in even grander terms. Muscivora derives from the Latin word for "fly" (musca) and "to devour" (vorare), while Forficata comes from forfex, or scissors. The scissortail now is a member of the genus Tyrannus, or "tyrant-like flycatchers."

Strong willed and fearless, the best comparison one can make to such a bird is the familiar Mockingbird who also readily defends territory, nest sites and has a qualification for fighting dirty. 

Scissor-Tailed Flycatcher perched high above an endless meadow of coneflowers near Piedmont Ridge Trail in the Great Trinity Forest
Scissor-Tailed Flycatchers hunt by sight and by ambush. Many see Scissortails lining barbed wire fences, telephone lines or even road signs. Those artificial perches afford great over watch of a field.

The photos here were taken entirely in wildscape. Meadows, fields and treelines along the Trinity River and in East/Southeast Dallas along lower White Rock Creek in an area called the Great Trinity Forest.
So many know White Rock Creek as it moves through North Dallas but so few ever see it beyond the outfall of the White Rock Lake Spillway where the creek slows, the trees get larger and the scenery much more photogenic.
A good look at a departing Texas Bird of Paradise, the Scissor-Tailed Flycatcher in full breeding plumage

Scissor-Tailed Flycatcher Attack Sequence On a Red-Tailed Hawk

Scissor-Tailed Flycatcher moves in on a trespassing Red Tailed Hawk
In some areas like the Trinity River Floodway, perches and tree cover for nesting sites are scarce. This is an area between the levees near the Industrial District and Downtown where lone Cottonwood and Pecan trees dot the landscape. They are the usual haunts of resident Red Tailed Hawks year round. When flycatchers come in to nest, there will be many nests in one tree as habitat is a premium. That leads to conflict and dramatic attacks result.

Red Tailed Hawks will actually prey on nests of other species. Documented cases of nestlings being eaten by hawks are well known. The Scissortail goes the extra mile to make a point with the Red Tailed Hawk in this photo, delivering what appears to be a quite painful strike to the back of the hawk's neck.
Contact with the hawk, the Scissortail is riding the hawk like a winged horse

The hawk screams in pain and maybe disbelief as the plucky Scissortail unleashes an aerial assault. Note the long Scissortail on the back of the hawk

Splash one hawk. The Scissortail returns to his nest.

This genus earned its name because several species are extremely aggressive on their breeding territories, where they will attack larger birds such as crows, hawks and even owls. Beautiful and ounce for ounce some of the heaviest hitters among Texas birds.

Rarely documented mirroring mating dance behavior of Scissor-tailed Flycatchers

Scissor-tailed flycatchers are easily identified by their long, scissor-like tail, which may reach nine inches in length. During flight, the bird opens and shuts its taillike a pair of scissors and folds or closes the "scissors" when perching. Since the bird is only 12 inches long, its tail is proportionately longer than any other Texas bird including Roadrunners.

The signature call of the Scissortail

Scissor-tailed flycatchers are considered Neotropical migrants birds that spend their winters in Central and South America, returning to North America to nest and raise young.

As a rule, scissortails are seen in Texas from early April to late October, though individuals occasionally are seen during the last week of March and some birds linger until mid-November.

Most likely their residency in Texas is tied to the first killing frosts of the Fall, which diminishes food supplies for the birds.
The scissortail is one of the earliest summer birds to arrive each spring. Across most of the Trinity River Corridor, Dallasites can begin looking for them during the first week in April. Their limited nesting range is primarily concentrated in the southern Great Plains states, from New Mexico to Louisiana and Nebraska southward to southern Texas and adjoining areas of Northern Mexico. However, the birds have wandered and documented as far north as Hudson Bay in Canada.
The brilliant colors of a Scissortail in near perfect light of a Texas sunset

The nape of the scissortail's neck and back are pearl gray, and the breast is white. Wings are smoke coal black with a touch of crimson at the shoulders while the sides and wing linings are pink. Females usually are shorter than males because her tail is not as long.

Breeding pair of Scissortail Flycatchers riding the stiff wind currents on the evening of June 16, 2014

A Scissortail bounds of the perch of a yucca to attack an unsuspecting insect below

Scissor-Tailed Flycatcher nest with four nestlings, June 13, 2014
The nesting habits for the Scissor-tailed Flycatcher include a small diamter stick nest lined with soft fiber material in an isolated tree where three to five eggs are laid. The female builds the nest and the male often adds the fiber material during the building process.
A Walking Stick becomes dinner for a Scissor-tailed Flycatcher nestling
Both parents work all day long to feed the nestlings. Moths, butterflies, June Bugs, grasshoppers and even Walking Sticks are standard table fare at these nests. 2014 seems to be a particularly banner year for these insects. Walking Sticks consume the foliage of oaks and other hardwoods. Severe outbreaks of the walking stick, Diapheromera femorata, have been documented in the Ouachita Mountains of Arkansas and Oklahoma. The insects eat the entire leaf blade. In the event of heavy outbreaks, entire stands of trees can be completely ravaged. Continuous defoliation over several years often results in the death of the tree. Birds like flycatchers help control the population of these insects.
Adult flycatcher removing waste from the nest site

Arkansas Yucca Yucca arkansana-- Photogenic Perch For Flycatchers

Native Yucca  in the brilliant sunset light growing on the bluff tops of the Trinity Forest
As a rule we think of Yucca as desert fare, but it is a common Texas plant often seen in undisturbed areas along the bluff tops of the Trinity River and White Rock Escarpment running through the Great Trinity Forest.

One  of the smallest yucca in Texas, Arkansas Yucca ranges from South Central to North Central Texas, into Oklahoma and Arkansas, preferring chalky pan soil on rocky hillsides and prairies. It has asymmetrical rosettes in small open groups.

Like most yucca, the leaves are bluish-green to yellowish-green with white margins and curly threads on the margin.

As is, the "stem" of the yucca looks woody (it has to be strong to support that mass of blooms.) Dead yucca leave a strong supporting "stick" for lack of a better term.  These particular groupings stand tall above the wildflowers, from 3 to 4 feet standard. 

There are over two dozen US species of these plants, much more widely distributed than agave, ranging across the Midwest, Great Plains and all the eastern states in addition to the south, in mixed environments including deserts, grassland, mountains and coastal scrub.

Yucca also extend through Mexico towards Central America. All species have the capability to grow tall and branch, though in some arid locations this does not happen, and the plants remain compact and single. Flowers are white and bell-shaped, growing in a great mass on a shortish stalk; they are usually produced once a year though may not appear if weather conditions are unfavorable.

Eastern Kingbird Tyrannus tyrannus
Eastern Kingbird Tyrannus tyrannus as seen hunting for insects among a grouping of wild Prairie Coneflower along a limestone escarpment along Lower White Rock Creek, Dallas Texas, 2014
The dressed to kill flycatcher of the Great Trinity Forest accolades go to that of the Eastern Kingbird Tyrannus tyrannus. A bird dressed in a tuxedo with fine lines and a descriptive ability to crush any and all insects that venture near.

The kingbird is easy to identify from other flycatchers with its contrasting black back and white chest, giving it the appearance of wearing formal dinner attire.  The black tail is tipped in white, making it easily recognizable. 

Black and white is not really the norm for flycatchers and songbirds. The Eastern Kingbird is unique in this way. Reds and yellows are more common.  But for what he lacks in color and song, he compensates for nicely in presentation and style.

An Eastern Kingbird weighs down an already blossom laden and top heavy Arkansas Yucca
Eastern kingbirds are flycatchers, which is considered the largest family of birds on Earth, with over 400 species.  The Eastern Kingbird exhibits that classic flycatcher silhouette, complete with the slight crown or ruffled head that is common among other flycatchers such as phoebes, wood pewees and so on.

Caught in mid air, an Eastern Kingbird hovers like a hawk in an effective technique to spook insects out of a hiding spot

Eastern Kingbirds also exhibit typical flycatcher behavior, called sallying, where they fly out from a perch in pursuit of flying insects, and then often returning back to the same perch (also called hawking). 

They feed mainly on insects during breeding season, but oddly enough, during migration and on their wintering grounds in South America, kingbirds change personalities and behave almost docile,  flying around in flocks, feeding on mainly fruit.
While as large as a Mockingbird and with similar colors, the Eastern Kingbird has a more robust and stockier build

Western Kingbird Tyrannus verticalis
Western Kingbird Tyrannus verticalis
One of the most common birds to spot in the Great Trinity Forest in spring are the hearty Western Kingbirds Tyrannus verticalis. From prairie areas of the Lower Chain of Wetlands to the deep swamps of Rochester Parks, these birds are visible at every turn from dawn to dusk.

Before the pioneer settlement of the Southern Plains the Western Kingbird range undoubtedly was restricted by the lack of advantageous perches in otherwise prime open country habitat.  Its range in Texas in the early 1900s was the western part of the state encompassing  the Panhandle, southern plains, and the mountains west and south of the Pecos River Valley.

Since the early 20th century, man’s opening of woodlands for timber harvest/farming, planting of trees on the plains, and construction of power lines, and other structures which accompanied settlement have facilitated expansion of Western Kingbird breeding range.

Nesting had spread by the mid 20th century east to Austin and by the late 1960s to the upper Texas coast.  By the early 1970s they were nesting in the Dallas Fort Worth area.
Western Kingbirds migrate from Central America to breed across the western United States during the spring and summer months--about April through the end of August/early September.

They leave their breeding grounds relatively early and are generally not seen in the western states from about mid-September through early May. They tend to be viewed around farms, meadows, and along fence rows near dry open fields with scattered trees and brush.

Western Kingbirds are members of the flycatcher family and are often seen hunting insects from fences and small bushes and trees along roadsides. They are about 9 inches long with a wingspan of about 16 inches. They have gray heads and chests, thick dark bills, yellow bellies, and dark tails with white edges. They can be aggressive and often harass large raptors

Western Kingbirds on guard

Just like Scissortailed Flycatchers, the Western Kingbird readily defends nest sites, habitat and favored trees from any predator or competing bird species. The telltale flash of yellow as the beat through the high grass is an easy way to spot these birds which very much resemble the Eastern Kingbirds, a distant cousin.