— This article by Jerry Cates was first published on 20 February 2019, and was last revised and expanded on 16 March 2019. Copyright Bugsinthenews Vol. 18:02(01)
Maternity nest of four Eastern Screech Owl (Otus asio) chicks, in a hole excavated in the cleft of a tree situated in a residential yard in south Austin, Texas. The hole opens to the sky, and is not visible from the ground, so this typical screech-owl nest had gone undetected for years. Three of the chicks are visible; the fourth had fallen out to the ground, but was rescued by the author and — after consulting with wildlife biologists familiar with this owl — returned to the nest post-photo. Note the chicks’ gray coloration. Eastern Screech Owls are found in gray and red color phases, sometimes in the same brood. The chick’s birth color is retained into adulthood and throughout the owl’s life. Most gray phase specimens are found in the northern portions of this owl’s native range, while the reddish phase is more common in the southern U.S. For some reason, however, the gray phase is also common in southern Texas.
The world’s magnificent Raptors, or birds of prey, symbolize those traits that most of us prize: freedom, wisdom, strength, and courage… Throughout history mankind’s various cultures have revered them as special animals with special powers that extend far beyond the puny capabilities of mere humans. Since time began we’ve thrilled at the sight of eagles, hawks, ospreys, kites, kestrels and harriers plying the skies with watchful eyes, spying tiny prey from far away, then swooping down with eerie precision to snatch their unsuspecting meals from riverbanks, meadows, tree limbs, and waterways… all in the wink of an eye.
At night, in the moonless dark of a forest glen, we’ve watched breathlessly as a huge, ghostly owl, all but invisible in the blackness of the evening hour, paces its domain, aloft on silent wings. It deftly dodges trees, rocks, and hillocks we scarcely see, then suddenly descends into the brush. We discern the muffled “squeak” from a rat, mouse, or rabbit, as the owl launches skyward, its talons clutched about a now-silent form whose squeals are forever quenched.
Traveling down our highways, we often chance upon the recumbent corpse of a deer, a dog, a raccoon or another animal that had foolishly taken up combat with a motorized vehicle and lost. It is common to find, surrounding its sad remains, a gathering of vultures, each taking its turn tearing putrefying flesh from the animal’s bones. Nearby other vultures watch impatiently, their ministerial-like garb suggestive of their roles as the undertakers of the animal kingdom. Even here we see majesty in form and function. What if these dark-robed creatures did not exist? What if they were not equipped with the gift of flight, eyes that spy their pungent quarry miles in the distance, and olfactory organs that alert them to prizes the eye cannot yet see? What if they were not so efficient at their gruesome profession that it takes twice or thrice the time to purify the grounds upon which the objects of their gustatory affections lie? The answer gives us pause, and makes us thankful…
Poets and scribes, in secular and sacred writings, have long extolled the raptor’s kingly style. In song, verse, and prose they urge their readers to draw inspiration from the raptor’s example. Obedient to these entreaties, mankind has drawn from a well, one buried deep in its collective soul, seeking to do all it could to meet that charge. Now our skies are filled with manmade contraptions that feebly imitate the still-mystic feats of our feathered friends, evoking but a fraction of the reverence attached to the latter. One senses that the awe filling our breasts with each raptor’s sighting will never wane, but will continue to thrill each generation of humanity that marches into the future.
Alas, though, despite these deeply-felt and widely shared sensibilities, mankind has too often mistreated the raptors we claim to revere. Sometimes our insults are intentional, hurled by ignorant brutes who either know not or care not about the consequences. More often, though, the insults perpetrated against raptors are dispatched by those who are unaware of the dastardly deeds they have committed.
History, though, dutifully documents those deeds, enabling us to revisit them and measure their results. Historical chronicles show how, for example, we nearly brought widespread extinction upon many raptor species with the worldwide use of DDT. In that case, we came to our senses in the early 1970’s, before it was too late. But history repeats itself, or — as Mark Twain is alleged to have put it — at least it rhymes: today we risk visiting similar fates upon our prized raptors with the unbridled dispensing of powerful, bio-accumulative rodenticides.
Based on these findings, mankind is awakening to the unintended collateral effects of modern-day do-it-yourself and professional pest control zealotry. Righting past wrongs has had an immediate, restorative effect. As a result, raptor populations everywhere are on the rebound, as pockets of enlightened folks contribute time, finances and intellect to become their protectors. We can, and must, do more, but we cannot expect a greater fraction of our fellows to join our throng until they comprehend the beneficent gifts these awesome creatures bestow on all mankind. Only then will humanity as a whole be so moved as to insist on curbing every insult directed their way.
So, with that worthy goal as the purpose of this paper, let us now begin…
We confine our study to the raptors of Texas, that is, to those raptors that are native to the state, or that spend some time here at some period during the year. The definition of “raptor” is often confined to those birds of prey within the taxonomical family Accipitridae. Here, however — following the convention used by a number of avian biologists — we will refer to all birds of prey, including vultures that feed primarily on carrion, as raptors.
It could be argued that even birds that are primarily terrestrial but that subsist mostly on insect, reptile, and rodent prey, should be included. The Greater Road Runner (Geococcyx californianus) is one of those.
The common denominator distinguishing raptors from other birds is their predatory behavior, one that leads to the conspicuous consumption of omnivorous animals such as commensal rodents. The environmental toxins that bioaccumulate in these omnivores are passed on to their predators, magnifying the toxic bioaccumulation found in the prey. As a result, birds of prey are more likely — as a group — to be affected by such toxins than practically all other animals on earth.
All raptors are members of the taxonomical class Aves (from the Latin avis, meaning “a bird”), but are grouped under several avian families, as described in what follows below. A brief description of each raptor species is provided on this page, to be followed when time permits by separate pages on each species, replete with photography of the birds themselves, their nests, and other pertinent features related to them.
Three Important Notes on Perspective…
— First: Don’t be Dismayed by the Details you will Learn about Raptor Violence and Raptor-on-Raptor Predation…
As you read through the accounts that follow, try not to be shocked by some of the native predatory habits of these birds. Each is a dedicated carnivore. As such, they all go about their daily lives killing and eating other animals. Some — such as the Osprey — restrict their selection of prey to fish. Most, however, are not that picky.
Many raptors include other birds in their diet, and — in general — songbirds are high on their list of preferred avian prey, even if they are just as fond of rodents. Some raptors, notably the falcons, mercifully kill their prey with lightning speed, using a notched ridge on their upper beak — known as the tomial tooth — to snap their spines and render them lifeless the instant they are caught; others, particularly owls, large hawks and eagles, take their prey alive, then dismember and consume them, often while they are still conscious (Fowler et al., 2009).
This amazing display of ghastly, unmerciful behavior is not surprising to those who study bird evolution. Modern animals typically reflect, at least to some degree, their genetic roots in the way they behave. The raptors are no different, and, as one would expect, the same is true for practically all birds, including those that we erroneously tend to think of as vegetarians. Many bird enthusiasts are shocked to find that only the geese subsist mainly on a vegetarian diet, and that even they will eat insects when the opportunity arises. All other birds are at least rapt insectivores that show no more mercy to their insect prey than raptors show to their bird and rodent prey. Many, like the raptors, are primarily carnivorous. As one would expect, their ancestry tells the tale.
The raptors, along with all other birds, are believed by most paleontologists to be the last remaining remnants of the carnivorous dinosaurs known as theropods. Though the exact lineage is not yet fully understood, as more fossil evidence is unearthed and studied, the linkage between the theropods and modern birds continues to strengthen. Our modern raptors, like their ancient, now extinct ancestors, have to employ a vicious, no-holds-barred modus operandi to survive as dedicated carnivores. Nobody would expect a meat-eating dinosaur to treat its quarry with anything like mercy. Seen in that light, the violent, dispassionate behavior of our modern raptors toward the objects of their gustatory urges is, perhaps, somewhat easier to comprehend.
In an ironic twist of fate, it happens that many raptors readily kill and consume other rodent-predator raptors. Of course, prey is prey, so they show no more mercy toward their own kind than to the rodents that both of them prey upon. For example, the Great Horned Owl, which is one of the more prolific rodent predators, preys on Screech Owls (which also prey on rodents). This trait, by the way, is not one that bird employs as an afterthought, for the Great Horned Owl is considered the Screech Owl’s most dangerous and persistent enemy.
— Second: Learn Why the Crucial Importance of Vigorous Rodent Control Justifies Overlooking Our Raptors’ Less Admirable Traits…
Serious rodent control is not an option — it is a non-negotiable imperative to which anyone who has knowingly fallen victim to a rodent-borne disease will attest. Unfortunately, much of the time our rodent-associated maladies are not recognized as such, so we usually don’t place the blame where it belongs. Whether we understand it or not, though, it is a well-established fact that rats and mice pose serious epidemiological risks to humans and our companion pets. They and the ticks, fleas, mites, and lice with which their exterior bodies are infested are all efficient carriers of serious, non-trivial human diseases. Inside their bodies, and by extension their urine and fecal pellets, lurk another long list of microorganisms and helminth parasites (worms) capable of causing morbid, even mortal, diseases.
The lesson is obvious to those who have studied the subject carefully: allowing rats and mice to nest, feed, defecate, and urinate in our homes and yards exposes us to a wide range of maladies. Children are most at risk to the ravages of these diseases, but so are adults and our companion pets. Dogs and cats sniff out rodent latrines, often licking up their urine stains and masticating and swallowing their pellets. In the process the pathogens brought by the rodents are efficiently transferred to our pets.
Contaminated and/or infected pets are capable of transferring those pathogens to every member of the household, including their loving adult-human owners and their children. Households with pets know all too well how efficiently what the dog or cat got into eventually gets around to the rest of the family. They are not termed “companion pets” for nothing; when the family pet wants to lick or rub or cuddle, we cannot deny them. The joy that comes from those intimate acts of bonding is one of life’s greatest pleasures, so avoiding it is not optional. Making sure that we do all we can to keep our companions away from rodent pathogens is, on the other hand, an important option we should — but often do not — take very seriously.
Some rodent borne diseases are life threatening, but many just make us miserable in the short term, and others lead to long-term quality of life issues whose origins, being murky at best, make it difficult for us to point fingers at the rodents behind them. I mention that because, when we are unaware of how our miseries originate, we cannot connect the dots, making it much too easy to overlook the importance of avoiding exposure to wild rodent activity.
Even if we dodge the worst of the rodent-borne diseases, those that cause less-than-lethal ailments can have a significant impact on the way we live, work, and play, both in the short term and later, as we grow older with the effects of those sub-lethal maladies lingering and impinging on our bodies in ways we scarcely imagine. Chances are, if we really knew about all the negative health effects of living with wild rats and mice nearby, we would be shocked into taking action. Do you sometimes wonder how some of your irritating maladies arrived at your figurative doorstep? Often, more than likely, they arrived at your literal doorstep, and local wild mice and rats worked the deliverance. Yet — because rats and mice are nocturnal and are often not seen even when they are present in large numbers — we rarely make the logical connection.
What should we do about that? I believe it is wisdom to make the dot-to-tot connections and, in recognition of what those interrelationships tell us, to do all that is reasonable to mitigate such exposures. Keeping rats and mice away is the best possible way to do that, without question.
So, here’s the big question: how should we keep rats and mice away? Well, for one thing, Mother Nature provides a very obvious way, one embodied in the form of, among other things — like snakes and other wild animals besides birds that prey on rodents — the raptors that eat rats and mice “for a living.” That singular trait makes them heroes despite having a long rap sheet of less admirable habits, such as killing and eating at least as many songbirds as rodents, and regularly making lunch of other raptors as well.
Absent their penchant for killing rats and mice, such nasty habits would make them villains of the first water. We rightly discount their villainous traits, though, out of appreciation for the good they do. We even take it a step further, by doing all we can to protect them. Anything that harms those birds of prey must be restricted to the point at which they cannot reduce their ability to keep rats and mice under control. Nobody can deny that makes excellent sense.
Earth Island Institute‘s (EAI) educational project known as Raptors Are The Solution, or RATS, teaches about birds of prey and the dangers posed to them by rodenticides. EAI is so invested in that concern that one of the most passionate objectives of the RATS project is to eliminate rodenticides from use everywhere, worldwide. I understand and empathize with that passion, for a number of good reasons. Some rodenticides are unnecessarily toxic. All rodenticides presently on the market can be, and often are, misused in ways that pose hazards to non-target animals including raptors and even humans. Most rodent bait stations are too easy to unlock, are easily broken into with the locks intact, and can be shaken and manipulated in a way that dislodges and spills out their bait contents without unlocking them.
For all those reasons we must stamp out careless and irresponsible rodenticide use where we live, work, and play. Responsible rodenticide use must employ rodent bait stations that are next to impossible to be unlocked by children or broken into by dogs, and whose contents cannot be shaken out with their locks intact. All those measures are within our reach, yet the RATS project proposes to eliminate rodenticides altogether. On the surface, that approach seems very straightforward and logical: No more rodenticides means fewer raptor poisonings, which means more raptors, which means fewer rats and mice. Makes sense, right? Maybe, but –then again — maybe not…
— Third: Do Not be Dismayed on Learning that Raptors, Alone, Cannot Keep Urban Rodents Under Control…
There is no question that raptors have a legitimate role in rodent control. As you read through the accounts that follow, below, that fact will become abundantly clear. What may not be as clear is that, while raptors are clearly part of the solution, they are not THE solution. Even those associated with the RATS project acknowledge this fact. On the RATS website that very point is made, though with descriptors that can be misleading. Raptors, the website asserts, though still “the” solution, are not “the entire” solution, so other measures must also be taken to help them out.
To further that end, the RATS website posts a list of six explicit steps that homeowners and renters should follow to discourage rats from taking up residence near their homes. So, does this mean that if you eliminate rodenticides, and follow those six steps, your rodent problems are over? That’s the implication, but — unfortunately — it is dreadfully wrong.
Let’s assume you, your neighbors, even your whole community outlawed local uses of rodenticides and followed the six steps posted on the RATS website religiously. The extra raptors in your skies, the ones now added because irresponsibly dispensed rodenticides no longer put a few of them in an early grave, would be able to keep rats and mice out of your yard and home, right? Sorry, but the correct answer is “No, they would not,” for one specific, well-known, and undeniable reason: rats and mice reproduce too fast in urban environments for any solely-natural control method to keep up.
That’s good news for raptors, by the way. It would not be good for them if they were so good at their trade that they greedily wiped out most of the rodents they rely on for food. Rodents constitute the main food supply for many of our raptors; if they decimated that food source, they’d be in serious trouble.
Where rodent populations are high raptors thrive and stick around. Where rats and mice are in short supply, raptors suffer and generally move away to places where their prey is more plentiful. That natural dynamic was illustrated, once again, during the recent 7-year drought that devastated all of Texas and our neighboring states. During that time not only were mice and rats in short supply in our meadows, forests, and wilderness areas, so were raptors, snakes, raccoons, skunks, and opossums, all of which depend to some extent on a regular diet of rats and mice to stay alive.
Yet, in urban environments, the chance introduction of just a couple of wild rodents — even in the midst of a devastating drought — can and often does, almost overnight, lead to a huge population of rodents in our yards and homes. With that population explosion comes, inexorably, all the epidemiological risks we discussed earlier. That’s not acceptable, no matter how you look at it, but — and this is the crux of the matter — raptors alone cannot keep that from happening.
So, if raptors are a serious part of the solution, but in all honesty cannot be considered THE solution to the problem of rats and mice, what is? Unfortunately, much as we may wish it wasn’t so, the only consistent, lasting control method known to man is the use of rodenticides.
The right rodenticide, placed in a secured, tamper-resistant container that cannot be accessed by children or pets, provides one of the most humane methods known to man for exterminating rodents. They are much more humane than snap-traps, for example, because more than 25% of the time the rodent that triggers a snap-trap is not killed outright; often only a limb or part of the rodent’s head is caught in the trap, and the hapless, conscious, and hurting rodent suffers for hours or days before death finally comes.
Electrocution traps, a relatively recent innovation, may be as humane as rodenticides (the jury is still out on that), but they have to be serviced immediately after the rodent is electrocuted, and with that service comes the need to come into close contact with a rodent carcass and the ectoparasites that have escaped its body; if the servicing individual does not properly treat the electrocution device and surrounding area with sterilants and vermicides, the risk of contamination can be severe.
Finally, lest we forget, it would be hard to imagine anything less humane than the experience of being dismembered alive by a raptor.
It must be repeated that rodenticides should be used judiciously, scientifically, carefully. and safely. They must not pose a risk to raptors (it is, indeed, possible to design a methodology that ensures that). And it must be recognized that — like raptors — they are still not THE solution, but only part of it, so their use must be augmented with a list of well-defined habitat modifications that convert yards and homes from rodent havens to places that do not attract or nurture them.
Of course, doing all that is not easy. In fact, the challenges to doing the job right, identifying obstacles in our paths, and recognizing the risks involved, are as daunting as any of the challenges faced by the pest management industry today. Yet, with the proper motivation and dedication, all those challenges can be met, all those risks can be mitigated, and all those obstacles can be overcome. Meeting all those objectives is, in fact, what the EntomoBiotics Inc. Enhanced Ecosystem Management & Control (EEMC™) program seeks to accomplish…
A Quick Note on Taxonomical Terms used in the Following
With many taxonomical names, a suggested pronunciation is provided. There is a good reason for this: If you can pronounce these sometimes-quite-long words, they actually come alive; if you cannot even imagine how to pronounce them, they acquire a poisonous kind of mystery that stunts learning by making them appear out of the intellectual reach of the reader. Don’t let that happen. Try to speak these words as you read along, and in the process of doing so, own them for yourself. If you fear you might “murder” the word, put such thoughts away. Taxonomy is a written, not a spoken, science. The pronunciation of a particular taxon is almost never sacrosanct. There is no really wrong, or truly right way to say these words. Within reason, anyone can pronounce a given taxonomical name any way one wishes, though a few loose rules have been adopted over time. The author does not pretend to have a lock on all those rules, but believes it is more important to help the reader feel as comfortable with the taxonomical terms presented than to fret about any mistakes he might make in the process…
Hawks and Eagles are members of the taxonomical family Accipitridae (pronounced ack-sih-PITT-trih-dee, from the Latin word accipiter, pron. ack-SIH-pih-tur, meaning “a hawk”); within this family are found the ospreys, eagles, kites, harriers, long-tailed hawks (accipiters), and broad-tailed hawks (Buteos, members of the genus Buteo, a Latin term, pron. BYEW-tee-oh, meaning “a buzzard,” which is the word used in Europe for these hawks, and does not refer to vultures, as has long been erroneously applied to the latter in the New World.)
The total number of birds of prey in the family Accipitridae known to be found in Texas varies according to the authority consulted. In John L. Tveten’s “The Birds of Texas” (Tveten, 1993) the number is 15, while in John H. Rappole & Gene W. Blacklock’s “Birds of Texas: A Field Guide,” (Rappole et al. 1994) the number is 26.
- Osprey (Pandion haliaetus): Though somewhat sexually dimorphic (the female is slightly larger), both sexes of this species are about the same size. Adult size (head to tail) ranges from 20-25 inches/51-64cm; wingspan ranges from 59-67 inches/150-150cm (Wheeler, 2018). This is a large, diurnal (day-active), piscivorous (fish-eating) bird, the osprey is found on all continents except Antarctica. Though most often found along coastal shorelines, this bird travels extensively throughout its range, fishing rivers, creeks, lakes, and streams. During the winter months it can be found along the Gulf coast and the Rio Grande Valley. It does not prey on mammals, and thus is not at risk from terrestrial placements of rodenticides. However, mercury residues in ospreys tested in Charlotte, NC, recently showed high levels (15.09mg/kg, 15 times the health threshold of 1mg/kg of body weight) for three specimens of this species, undoubtably due to high mercury levels in the fish they’d preyed upon. The same study also found mercury levels above the health threshold in a red-shouldered hawk and an eastern screech owl.
- Hook-billed Kite (Chondrohierax uncinatus): This species is omitted by Tveten because it rarely intrudes into the south Texas counties of Hidalgo and Starr from its native range of north Mexico to southern South America. According to the Audobon Society, it was first seen in Texas in 1964, and has been seen in south Texas with regularity, usually in pairs or in family groups, since 1975. It feeds primarily on tree snails, supplemented with frogs, salamanders, and insects. “Tree snail” is a label applied to tropical air-breathing terrestrial snails with shells that live exclusively in trees. Most tree snails subsist exclusively on the fungal growths infecting tree trunks and limbs.
- American Swallow-tailed Kite (Elanoides forficatus): Size, head to tail, 20-25 inches/51-64 cm; wingspan 57-54 inches/119-137cm (Wheeler, 2018). This is an aerial hunter that feeds on flying insects, arboreal frogs, lizards, reptiles, and nestling birds (Wheeler, 2018). Though a rare transient along the Texas Gulf coast two decades ago, the previous population decline appears to have stabilized, and now may be on the increase. This raptor appears to be primarily insectivorous, feeding mostly on flying insects such as dragonflies and cicadas. It will also snatch snakes, nestling birds and eggs from the treetops it skims over. In its wintering grounds of South America, it is often observed eating fruit.
- Black-winged Kite (Elanus caeruleus): Also known as the Black-shouldered Kite, but because that name causes confusion with an Australian kite with the same common name, the Black-winged version is now preferred (adding to this confusion, however, is the use of this same common name for another unrelated species, Milvus migrans). It is a broad-ranging bird that ranges over much of the Americas, Africa, and Asia, and is considered one of the most common raptors within this range. It is a small, diurnally active bird of prey, with long wings, creamy white, gray, and black plumage, and forward-facing owl-like eyes with red irises. It flies slowly, much like a harrier, while foraging, but often hovers over meadows and grasslands, its wings only slightly moving, as kestrels are wont to do. Its prey includes grasshoppers, crickets, cicadas, lizards, rats, mice, birds, snakes and frogs; in Africa, studies have shown that 80% of this bird’s prey consists of rodents; a typical adult consumes at least 2 mice a day, which would represent 25% of its average 250g body weight. This author remembers one memorable sighting, fifteen or so years ago in Fort Worth, Texas, when a black-winged kite snatched a sparrow from a tree limb less than five feet away, then flew up into a nearby tree to dismember and consume its meal.
- White-Tailed Kite (Elanus leucurus): Though somewhat sexually dimorphic (the female is slightly larger), both sexes are about the same size. Size (head to tail) 14-16 inches/36-41cm; wingspan 37-40 inches/94-102cm (Wheeler, 2018). According to one authority (Wheeler, 2018) this raptor is fairly to locally common in Texas, with a permanent range that includes the Gulf Coast, portions of the Rio Grande Valley, and small pockets along major rivers and lakes.
- Snail Kite (Rostrhamus sociabilis): subsists almost exclusively on aquatic apple snails. Accidental intruder into south Texas, and rarely observed.
- Mississippi Kite (Ictinia mississippiensis): Though somewhat sexually dimorphic, inasmuch as the female tends to be slightly larger, both sexes are about the same size. Size, head to tail, 12-15 inches/30-38 cm; wingspan 29-33 inches/74-84cm (Wheeler, 2018). This gregarious raptor roosts, feeds, and migrates in flocks, and often nests communally. It is an aerial hunter, subsisting mostly on flying insects, tree-inhabiting amphibians, lizards, and nestling birds; it rarely captures terrestrial rodents. It is an uncommon summer resident in most of the panhandle, central, and east Texas including the Gulf Coast outside of its core breeding areas, but is a locally common summer resident in some portions of Texas; in west Texas, and inland to the Rio Grande valley; in the Trans-Pecos it is rarely sighted.
- Bald Eagle (Haliaeetus leucocephalus, from the Greek roots ἅλς, hals = “sea”; αἰετός, ai-EE-tos = “eagle”, λευκός, loo-KOS = “white”, κεφαλή, keff-HALL-ee = “head”): Females are larger; adults of both sexes range in length, head to tail, 27-37 inches/69-94cm. The Bald Eagle was approved by th U.S. Congress as our national emblem on 20 June 1782, edging out the Golden Eagle based on two considerations. First, the Golden Eagle, which is found throughout the Northern Hemisphere, had already been honored as the national emblem of a number of other nations. Today, following a trend that continues unabated, the Golden Eagle remains the most common national symbol worldwide, including the nations of Scotland, Afghanistan, Egypt, Germany, Spain and Mexico (the eagle honored by Austria and several other nations is the Black Eagle). Second, and perhaps more germane, the Bald Eagle is only found in the New World, and here its range is confined to the Northern Hemisphere, where it can be found throughout the continental U.S., southern Alaska, most of Canada and Greenland. Further, it is considered by many avian biologists as the largest of the true raptors found in North America, being on average 455 grams heavier than the Golden Eagle, though the latter on average has a wing span some 3 cm greater than that of the Bald Eagle. Arguments against its selection as the U.S. national emblem included the assumption that rather being primarily a hunter — as is the Golden Eagle — the Bald Eagle is thought by some to be primarily a scavenger. That assertion, and other similar negative claims regarding the Bald Eagle’s behavior, are much in dispute, but once led to a regular slaughter of this bird by hunters who believed they were performing a public service by taking out as many Bald Eagles as they could. That practice was brought to a halt, but not before Bald Eagle populations had been decimated throughout the U.S. It is fortunate that their populations have rebounded once they were accorded protection from wanton destruction. Though listed as Endangered on March 11, 1967, this raptor was down-listed to Threatened some 28 years later, on July 12, 1995, and delisted entirely 12 years afterward, on 8 August 2007. Today the Bald Eagle is recognized as a skilled aerial and perch hunter that feeds mainly on live prey during the nesting season, but often scavenges in other seasons; fish is its main prey, but waterfowl, jackrabbits, and large rodents such as prairie dogs are also taken in areas away from water. In Texas, Bald Eagles — which are monogamous and mate for life — nest from October to July; their large nests, which females construct with help from their mates, is made of large sticks covered with Spanish moss, and is re-used year after year with regular amendments of added materials. They can be found in isolated pockets year-round throughout the northern half of the Texas panhandle, and in central, north, and east Texas, with breeding populations concentrated in southeast Texas along the Gulf Coast, and non-breeding and wintering populations concentrated in the Panhandle, and in Central and East Texas.
- Northern Harrier (Circus cyaneus): Sexually dimorphic, with the size of the male, head to tail, 16-18 inches/41-46cm, and a wingspan of 38-43 inches/97-109cm; the size of the female, head to tail, is 18-20 inches/46-51 cm, and a wingspan of 43-48 inches/109-122cm (Wheeler, 2018). Also known as the Marsh Hawk, this is an aerial hunter that preys on rodents, hares, rabbits, small to mid-size birds and large ducks; it sometimes consumes amphibians, reptiles, and large insects; it readily consumes carrion in the wintertime (Wheeler, 2018). This is a common winter resident throughout Texas, arriving in September and remaining through March. It forages in a distinctive way, flying low over meadows and open areas, mostly gliding but flapping its wings from time to time, then hovering with flapping wings when spying prey.
- Sharp-shinned Hawk (Accipiter striatus): Sexually dimorphic and distinguishable in the field with practice, with the size of the adult male, head to tail, 9-11 inches/23-28cm, and a wingspan of 20-22 inches/51-56cm; the size of the female, head to tail, is 11-13 inches/28-33 cm, and a wingspan of 23-26 inches/58-66cm (Wheeler, 2018). This is an aerial and perch hunter of songbirds (Wheeler, 2018). It is a common winter resident throughout Texas.
- Cooper’s Hawk (Accipiter cooperii): Sexually dimorphic, and separable in the field, with the size of the adult male, head to tail, 14-16 inches/36-41cm, and a wingspan of 28-30 inches/71-76cm; the size of the adult female, head to tail, is 16-19 inches/41-48cm, and a wingspan of 31-34 inches/79-86cm (Wheeler, 2018). This is an aerial and perch hunter of songbirds and small upland game birds, rodents, and lizards (Wheeler, 2018). Like the Sharp-shinned Hawk, this is common winter resident throughout Texas except for the panhandle, where it is scarce; it is a permanent resident of the inland regions of north, east and south Texas.
- Northern Goshawk (Accipiter gentilis): Sexually dimorphic, sexes not easily distinguished in the field, with the size of the adult male, head to tail, 18-20 inches/46-51cm, and a wingspan of ?? inches/??cm; the size of the female, head to tail, is 21-24 inches/53-61 cm, and a wingspan of ?? inches/??cm (Wheeler, 2018).This is an aerial and perch hunter of Snowshoe Hare, Ruffled Grouse, squirrels, large passerines and woodpeckers, and waterfowl (Wheeler, 2018). It is a winter resident of the Trans-Pecos and western panhandle of Texas.
- Crane Hawk (Geranospiza caerlenscens):
- Common Black-Hawk (Buteogallus anthracinus): This is a perch hunter of fish, amphibians, reptiles, small mammals, birds, and large insects (Wheeler, 2018). It is an infrequent summer resident of small pockets scattered throughout the state.
- Harris’ Hawk (Parabuteo unicinctus): This is a perch hunter that takes prey as large as jackrabbits but mainly eats rabbits, quail, songbirds, and lizards (Wheeler, 2018). It is a permanent resident of the Texas Hill Country, northeastern Trans-Pecos, central and south Texas.
- Gray hawk (Buteo nitidus): This is a perch hunter that feeds primarily on lizards but also eats small birds, rodents, and large insects (Wheeler, 2018). It is very common in north Mexico, and is a permanent resident of small pockets along the Rio Grande Valley of Texas.
- Roadside Hawk (Buteo magnirostris):
- Red-shouldered Hawk (Buteo lineatus): Size of the adult male and female, head to tail, is 15-19 inches/38-48cm, with a wingspan of 37-42 inches/94-107cm; females are larger than males (Wheeler, 2018). This is mainly a perch hunter that eats small mammals, amphibians, reptiles, invertebrates, small birds, fish, insects, and carrion (Wheeler, 2018). The Eastern subspecies (Buteo lineatus lineatus) is a common winter resident of the eastern half of Texas, but is not a permanent resident anywhere within the state; the Southern subspecies (Buteo lineatus alleni) is a permanent resident of much of the eastern half of Texas, and a winter resident of central, east, and south Texas as well (Wheeler, 2018).
- Broad-winged Hawk (Buteo platypterus): Females are larger, with adults of both sexes having a head-to-tail length of 13-17 inches/33-43cm, and a wingspan of 32-36 inches/81-91cm. This is a perch hunter, perching on exposed and concealed objects, including utility poles and wires; it eats small amphibians, insects, reptiles, and rodents that it catches on the ground or on outer branches in direct flight, rarely by diving (Wheeler, 2018). It is a common summer resident of far east Texas, less frequently a summer resident of portions of central Texas.
- Short-tailed Hawk (Buteo brachyurus): This is strictly an aerial hunter of sparrow-to-Jay-sized birds, chipmunks, and lizards (Wheeler, 2018). It is an infrequent summer resident of small pockets of east, south, and west Texas.
- Swainson’s Hawk (Buteo swainsoni): Females average larger, with adults of both sexes having a head-to-tail length of 17-21 inches/43-53cm (Wheeler, 2018). This is a perch and aerial hunter of open-area small rodents and large insects such as grasshoppers, small birds, and reptiles (Wheeler, 2018). It is a common summer resident of the Texas panhandle and west, central, and south Texas.
- White-tailed Hawk (Geranoaetus albicaudatus): This is a perch and aerial hunter of amphibians, reptiles, small mammals, and terrestrial birds; it readily eats carrion (Wheeler, 2018). It is a permanent resident of the Gulf Coast of Texas, a winter resident of south Texas, and an infrequent summer resident of small areas throughout the state.
- Zone-tailed Hawk (Buteo albonotatus): This is a low-altitude aerial hunter of terrestrial lizards, small birds, and rodents (Wheeler, 2018). It is a summer resident of scattered pockets throughout the southern half of Texas, and a winter resident of scattered pockets within that range.
- Red-tailed Hawk (Buteo jamaicensis): Females average larger, and juveniles are longer than adults because of typically longer tails, with adults ranging from 17-22 inches/43-56cm, head to tail (Wheeler, 2018). This is a perch and aerial hunter of small to medium-sized amphibians, birds, mammals, and reptiles (Wheeler, 2018). The Eastern subspecies (Buteo Jamaicensis borealis) is a permanent resident of the Texas panhandle, north, central, and east Texas, and a winter resident of the southern half of Texas excluding the Trans-Pecos; Krider’s Red-tailed Hawk (B. j. kriderii) is a winter resident of central and east Texas; the Western Red-tailed Hawk (B. j. calurus) is a winter resident of all portions of Texas, and a permanent resident of some portions of the northwestern Trans-Pecos; Harlan’s Red-tailed Hawk (B. j. harlani) is a winter resident of central, north, and east Texas; Fuertes Red-tailed Hawk (B. j. fuertesi) is a permanent resident of southwestern Texas, and a winter resident of the southern tip of the state;
- Ferruginous Hawk (Buteo regalis): Females average larger, with adults of both sexes ranging in length, head tail, 20-26 inches/51-66cm. This is a perch and aerial hunter of ground squirrels, prairie dogs, rabbits, hares, terrestrial birds, insects, reptiles, and carrion (Wheeler, 2018). It is a common winter resident of the Texas panhandle, west, central, north, and south Texas.
- Rough-legged Hawk (Buteo lagopus): Females average larger, with adults of both sexes ranging in length, head to tail, 18-23 inches/46-58cm. This is an aerial and perch hunter of small rodents (Wheeler, 2018). It is a winter resident of the Texas panhandle, the Trans-Pecos, north and central Texas,
- Golden Eagle (Aquila chrysaetos): This is a perch and aerial hunter, with mated pairs hunting cooperatively; spring and summer prey includes mammals, from rabbits to small deer, large waterfowl, upland game birds and birds as large as the Great Blue Heron; fall and winter prey is primarily carrion (Wheeler, 2018). This is an uncommon winter resident of the Texas panhandle and west Texas, with some local permanent residents in those areas as well.
Caracaras and Falcons are members of the taxonomical order Falconiformes (fowl-kahn-uh-FOHR-mees), and the taxonomical family Falconidae (fowl-KAHN-uh-dee, from the Latin word Falco, meaning “a falcon”). A comparative genome analysis published in 2008 provided evidence that the caracaras and falcons are more closely related, genetically, to parrots and passerines than to other raptors. In 2011, an analysis of transposable element insertions shared between falcons, passerines and parrots but absent in the genomes of other birds, confirmed the genetic relationships evidenced in the earlier study. Worldwide the Falconidae family presently contains around 60 species of diurnal birds of prey, divided into two subfamilies. The subfamily Polyborinae (polly-BOHR-enn-ee) contains the caracaras and forest falcons, and the subfamily Falconinae, which contains the falcons and kestrels.
Texas has three (Tveten, 1993) or six (Rappole et al., 1994) birds of prey in this family.
- Crested Caracara (Polyborus plancus): This raptor subsists primarily on carrion, but will take small prey dislodged by fire or plowing as well (Wheeler, 2018). It is a permanent resident of south Texas, and in small pockets of central, north, and east Texas.
- American kestrel (Falco sparverius): This is a perch and aerial hunter of large insects, small rodents, songbirds, reptiles, and amphibians (Wheeler, 2018). It is a permanent resident of the Texas panhandle, north Texas, portions of central east Texas, and the Trans-Pecos, and a winter resident throughout the state.
- Gyrfalcon (Falco rusticolus): This is a perch and aerial hunter of birds up to the size of geese, and mammals to the size of hares (Wheeler, 2018). In Texas, it has only been sighted in the city of Lubbock.
- Merlin (Falco columbarius): This is an aerial hunter of small birds and large insects (Wheeler, 2018). The Taiga Merlin (Falco columbarius columbarius) is a winter resident of central, north, south, and east Texas; Richardson’s Merlin (F. c. richardsonii) is a winter resident of the Texas panhandle, north, central, west Texas, and the Trans-Pecos; the Black Merlin (F. c. suckleyi) is a rare winter resident of the Gulf Coast of Texas.
- Aplomado Falcon (Falco femoralis): This is a predator of birds ranging from sparrow to Mourning Dove in size, of large insects such as cicadas, and — especially along the Gulf coast — of crustaceans and amphibians (Wheeler, 2018). It is a permanent resident of the Gulf coast, and areas in the Trans-Pecos.
- Peregrine Falcon (Falco peregrinus): This is an aerial hunter of small songbirds, shorebirds, large ducks, and small mammals (Wheeler, 2018). In Texas, the Arctic Peregrine Falcon (Falco peregrinus tundrius) is a common winter resident of the Gulf Coast; and the Anatum Peregrine Falcon (F. p. anatum) and Eastern Peregrine Falcon (n.s.d.) are common winter residents of north, central, east, south Texas and the Trans-Pecos.
- Prairie Falcon (Falco mexicanus): This is a perch and aerial hunter that feeds mainly on passerines, small game birds, and mammals as large as rabbits during the non-breeding season; feeds readily on carrion. It is common winter resident of much of Texas, excluding the eastern half of the state; permanent residency occurs in pockets in the northern panhandle and the Trans-Pecos.
American or New World Vultures are members of the taxonomical family Cathartidae (kuh-THAR-tuh-dee, from the Greek word καθαρός, pron. KATH-uh-rohs, meaning to cleanse, purify). This family is confined to the Western Hemisphere, and contains seven species in seven genera, divided into two groups of five vultures and two condors. The condors are the largest flying land birds in this hemisphere; neither species is found in Texas.
Of the five species of vultures found in the Americas, two — the black vulture and the turkey vulture — are found in Texas.
- Black Vulture (Coragyps atratus): This species is not sexually dimorphic, so both sexes are about the same size. Size, head to tail, 23-28 inches/58-71cm; wingspan 53-63 inches/135-160cm (Wheeler, 2018). This vulture is aptly named, being clothed in black feathers, with — at all ages — a naked, black-skinned head and upper neck, white legs, and six white wingtip fingers visible in flight. Distinguished in flight habits from the Turkey Vulture in that it normally does not soar, but glides at low levels with its wings held flat, while alternately flapping its wings. It is common to the eastern half of Texas, less common in the western half.
- Turkey Vulture (Cathartes aura): Like the black vulture, this species is not sexually dimorphic, so both sexes are about the same size. Size, head to tail, 24-28 inches/61-71cm; wingspan 63-71 inches/160-180cm (Wheeler, 2018). This vulture is black, with — in the adult — a naked red-skinned head and upper neck (the head and neck in recently fledged and early stage juveniles range from a dark gray, to a dark reddish gray), and with pale, silvery feathers at its underwing wingtips. It is a common resident throughout Texas in the summertime, and a permanent resident of the eastern half of Texas year-round.
Owls are members of the taxonomical order Strigiformes. The order is divided into two families, the Strigidae (true or typical owls) and the Tytonidae (barn owls).
Barn Owls, members of the taxonomical family Tytonidae, is composed of 12 species. Only one of these is regularly found in North America:
- Common Barn Owl (Tyto alba): This tawny and gray owl, with large dark eyes, a white face with features reminiscent of a monkey, and long legs, is common to the eastern half of Texas, less common in the western half of the state.
True, or Typical Owls, members of the taxonomical family Strigidae (from the Latin word strix, meaning “screech owl”). This large family, which is represented on all continents except Antarctica, is subdivided into 25 genera embracing about 200 living species. They are nocturnally active, with large heads, shortened tails, and eyes surrounded by disc-shaped feather contours specially positioned to amplify and direct sounds to their ears. Feathers covering their bodies are soft, with downy bases, and those on the leading edge of each wing are serrated, all of which features work to facilitate silent flight. Their large eyes and quiet demeanor in the presence of humans convey a sense of contemplative wisdom, and give rise to the kindred notions that they can see well even under extremely dark conditions, but are visually impaired in the daytime; neither notion is correct, however.
Texas is home to either six (Tveten, 1993) or sixteen (Rappole et al., 1994) true or typical owl species:
- Flammulated Owl (Otus flammeolus): Found principally in the Trans-Pecos region of Texas, where it is a rare summer resident.
- Eastern Screech-Owl (Otus asio): Found principally in the eastern half of Texas, less often in western half of the state, rarely in the Texas panhandle. Distinguished from the Western Screech-Owl by having a pale-colored bill, while the Western Screech-Owl has a darker bill.
- Western Screech-Owl (Otus kennicottii): Found principally in the Trans-Pecos region of Texas.
- Great Horned Owl (Bubo virginianus): Found throughout Texas, where it is a permanent resident. See the author’s article on the humane exclusion of this species of owl from a commercial structure in Austin. Texas (2012).
- Snowy Owl (Nyctea sandica): This owl is primarily found in the northern polar regions of the Old and New World, and is but a casual winter visitor to Texas, arriving in north and central areas of the state in December, but departing by early March.
- Northern Pygmy Owl (Glaucidium gnoma): A casual transient in the Guadalupe Mountains National Park, Culberson County, Texas, where it resides from April to May in the springtime, and August to September in the fall.
- Ferruginous Pygmy Owl (Glaucidium brasilianum): This small, long-tailed owl is a rare permanent resident in the Lower Rio Grande Valley of Texas.
- Elf Owl (Micrathene whitneyi): This small, short-tailed owl is an uncommon summer visitor to the Big Bend region of the Trans-Pecos, rarely sighted in the Lower Rio Grande Valley.
- Burrowing Owl (Athene cunicularia): This is a long-legged, terrestrial owl that is often associated with prairie dog towns. It is a common summer resident of the western half of Texas, less commonly found in the eastern half of the state.
- Mottled Owl (Ciccaba virgata): This is rarely found in south Texas, specifically in Hidalgo County, where it is considered an accidental visitor.
- Spotted Owl (Strix occidentalis): This large, dark-eyed owl is a rare permanent resident of the mountains of the Trans-Pecos.
- Barred Owl (Strix varia): This large, dark-eyed owl is similar in appearance to the Spotted Owl; it is commonly found throughout the eastern half of Texas, and is a common permanent resident of portions of the Texas Gulf Coast, particularly in the vicinity of Sinton and Corpus Christi.
- Long-eared Owl (Asio otus): A medium-sized owl with yellow eyes and long ear tufts, similar in appearance to the Great Horned Owl. It is a rare winter resident in Texas, where sparse sightings have been made throughout the state, usually during the period from November to April.
- Short-eared Owl (Asio flammeus): A medium-sized owl with short ear tufts and yellow eyes. It is a crepuscular forager that paces low over open meadows and fields in much the same manner as the Northern Harrier (Circus hudsonius or Circus cyaneus hudsonius), or Marsh Hawk. It is an uncommon winter resident of the eastern third of Texas, sighted mostly from October through April.
- Northern Saw-whet Owl (Aegolius acadicus): This small, dark brown, white-spotted, yellow-eyed owl is a casual winter visitor to the northern half of Texas.
This paper is a work in progress. Please bear with us as it is fleshed out…
Taxonomy: in progress…
- Arnold, Keith A, & Gregory Kennedy. 2007. Birds of Texas. Lone Pine Publishing.
- Clark, Gary, & Kathy Adams Clark. 2018. Book of Texas Birds. Texas A&M Press.
- Cooper, Tim, et al. 2007. Basic Texas Birds: A Field Guide. University of Texas Press.
- Fowler, Denver W., et al. 2009. Predatory Functional Morphology in Raptors: Interdigital Variation in Talon Size is Related to Prey Restraint and Immobilisation Technique. PLOS
- Lockwood, Mark W. & Brush Freeman. 2014. The TOS Handbook of Texas Birds, 2nd Edition. Texas A&M University Press.
- Rappole, John H., & Gene W. Blacklock. 1994. Birds of Texas; A Field Guide.
- Takiela, Stan. 2004. Birds of Texas Field Guide. Adventure Publications.
- Tveten, John L. 1993. The Birds of Texas. Shearer Publishing.
- Wheeler, Brian K. 2018. Birds of Prey of the East: A Field Guide. Princeton University Press.
- Wheeler, Brian K. 2018. Birds of Prey of the West: A Field Guide. Princeton University Press.
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