Tag Archives: cattle egret (Bubulcus ibis)

Tropical haven

There is a place where spring calls forth all the magic of the tropics …

White ibises (Eudocimus albus) flying overhead (2009_05_17_019243)

A place where white ibises circle overhead …

A great egret (Ardea alba) collecting nesting material in the understory (2009_05_17_019056)

A place where great egrets lurk in the understory …

A little blue heron (Egretta caerulea) perched on a branch (2009_05_17_019428)

A place where little blue herons keep watch at eye level …

A black-crowned night-heron (Nycticorax nycticorax) perched in a tree (2009_05_17_019912)

A place where black-crowned night-herons peer back from their ligneous perches …

A snowy egret (Egretta thula) perching on a limb (2009_05_17_019767)

A place where snowy egrets observe the observers …

Close-up of a tricolored heron (a.k.a. Louisiana heron; Egretta tricolor) perched in a tree (2009_07_12_026569_n)

A place where tricolored herons remain vigilant even at rest …

A cattle egret (Bubulcus ibis) standing in a tree displaying its mating plumage (2009_05_17_019354)

A place where cattle egrets display their beauty …

It’s amazing that this tropical haven rests just a few miles north of downtown Dallas.

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Photos (taken at the University of Texas Southwestern Medical Center campus in Dallas’s hospital district):

  1. White ibises (Eudocimus albus)
  2. Great egret (Ardea alba)
  3. Little blue heron (Egretta caerulea)
  4. Black-crowned night-heron (Nycticorax nycticorax)
  5. Snowy egret (Egretta thula)
  6. Tricolored heron (a.k.a. Louisiana heron; Egretta tricolor)
  7. Cattle egret (Bubulcus ibis)

Always fleeting

Life moves pretty fast.  If you don’t stop and look around once in a while, you could miss it.
— Ferris Bueller (Matthew Broderick) in Ferris Bueller’s Day Off

Sometimes they chase their shadows.

A velvet ant (Dasymutilla sp.) in flight (IMG_3659)

Sometimes their shadows chase them.

A giant swallowtail (Papilio cresphontes) in flight (IMG_3537)

And sometimes their shadows hide beneath them, holding them up, providing the foundation upon which they travel.

A Virginia opossum (a.k.a. possum or tlacuache; Didelphis virginiana) trotting through a clearing (2009_04_19_016210)

Observing wildlife is one thing, but photographing it is another.  Because life is always fleeting.

A juvenile American robin (Turdus migratorius) in flight (2009_09_06_028805)

Sometimes together.

Rock doves (a.k.a. common pigeons; Columba livia) in flight (2008_12_07_000543_ab)

Sometimes alone.

A nutria (a.k.a. coypu; Myocaster coypus) swimming in calm water (2009_06_01_021672)

Sometimes in the city.

A cattle egret (Bubulcus ibis) in flight (2009_05_17_019619)

Sometimes in the wild.

A diamondback water snake (Nerodia rhombifer) swimming through a creek (2009_06_06_022472)

Sometimes up close.

A variegated fritillary (Euptoieta claudia) in flight (IMG_3174)

Sometimes at a distance.

A Forster's tern (Sterna forsteri) in flight (2009_12_26_046986)

But always fleeting.

A white-lined sphinx (Hyles lineata) in flight (2009_07_18_026922)

Yes, life moves pretty fast.  If you don’t stop and look around once in a while, you could miss it.

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  1. Velvet ant (Dasymutilla sp.) flying over open ground in East Texas; this female will lose her wings and become a typical velvet ant as soon as she selects a good hunting-cum-nesting site
  2. Giant swallowtail (Papilio cresphontes); this is the largest butterfly in Canada and the United States
  3. Virginia opossum (a.k.a. possum or tlacuache; Didelphis virginiana); this is the only marsupial found north of Mexico
  4. Juvenile American robin (Turdus migratorius)
  5. Rock doves (a.k.a. common pigeons; Columba livia)
  6. Nutria (a.k.a. coypu; Myocaster coypus)
  7. Cattle egret (Bubulcus ibis) in breeding plumage
  8. Diamondback water snake (Nerodia rhombifer)
  9. Variegated fritillary (Euptoieta claudia)
  10. Forster’s tern (Sterna forsteri)
  11. White-lined sphinx (Hyles lineata)

Invasive versus introduced

I’ve focused a good deal of blog bandwidth of late on nonnative species in Texas, including blackbucks, aoudads, and various types of deer.  Then I expanded my focus beyond Texas so as to include the now ubiquitous house finch, a bird native only in the southwestern third of North America.  In each case—as throughout my years of blogging—I have religiously defined these species as “introduced” rather than “invasive” in much the same way that I define European starlings and house sparrows as “introduced” rather than “invasive”.

It is that distinction which spurred Seabrooke to leave this relevant comment:

I define “introduced” and “invasive” a little differently than you do, I think. I don’t find the two terms mutually exclusive. Introduced simply means to me that the species is non-native, and that it has been, whether intentionally or not, introduced by humans to an environment where it didn’t previously occur and would likely never have reached on its own. Invasive in my mind refers to the nature of what a species does when it finds itself in a new place — some may sit docilely where they were put and never spread very far (many garden plants and flowers fall into this category), but some others love their new location so well that they go crazy and start spreading out from where they were put. Some introduced species may not necessarily be invasive, while some invasive species could very well be native (especially true in disturbed areas, since it’s harder for anything — introduced or otherwise — to gain a foothold in an area of stable habitat; unfortunately, our human activities mean that few habitats are truly undisturbed anymore).

As I explained in my response to that comment, I agree with her use and definitions of those terms.  My tendency to mark a clear delineation between the two is intentional and strategic.  By way of explaining that answer, let me introduce you to some truly invasive species.

A male great-tailed grackle (Quiscalus mexicanus) standing on the ground (2010_04_10_052604)

Great-tailed grackles (Quiscalus mexicanus).  Their northernmost range stopped in far South Texas as of 1900.  Since then, however, they have exploded northward and westward such that now they occur year-round throughout Texas and north through Oklahoma to Kansas, and west through Colorado, Utah, Nevada and California—all the way to the Pacific Coast.  Smaller migratory breeding populations stretch into Missouri and Nebraska.

A female great-tailed grackle (Quiscalus mexicanus) standing on a pier (2008_12_07_001394)

Great-tailed grackles continue to expand their range in North America and southward into the northern parts of South America.  This expansion is invasive as they are endemic to Mexico south to Columbia.  Unlike species introduced by people, whether intentionally or otherwise, these birds have expanded their range naturally into areas where they now compete with—and in many cases out-compete—indigenous fauna.

A male great-tailed grackle (Quiscalus mexicanus) standing on the ground (2010_04_10_052647)

Yet because their presence is natural, even though it is invasive, they are tolerated—even celebrated—by the same nature purists who decry and bemoan European starlings and house sparrows, calling these latter two species invasive, and who enjoy house finches east of the Rocky Mountains as though they belong there.

But let’s not stop with great-tailed grackles.  Instead, let’s look at an even more invasive species of bird, one that has invaded most of the planet and is responsible for one of the fastest and largest territorial expansions of any avian species: the cattle egret (Bubulcus ibis).

A cattle egret (Bubulcus ibis) standing atop some twigs (2009_05_17_019108)

Native to eastern Africa, these birds first arrived in South America in the late 1800s.  They flew across the Atlantic Ocean to get there.  The first confirmed cattle egret was documented in North America—in Florida—around 1940.  By 1996 they had occupied the entire continental United States and southern Canada.

A cattle egret (Bubulcus ibis) displaying in a treetop (2009_06_20_023921)

Their global invasion carried them to islands far and wide, not to mention all of Eurasia.  In fact, they have established themselves nearly everywhere except in extreme or unwelcoming environments, such as mountain ranges, polar regions, deserts and boreal forests.  Aside from those places where they can’t survive, they seem destined to occupy the entire planet, a feat they are accomplishing in short order.

A cattle egret (Bubulcus ibis) perched on a limb (2009_06_20_024031_f)

Interestingly, their range is still expanding where they have invaded and their dispersal from Africa is ongoing.  It might be said that as truly invasive species are concerned, cattle egrets are second only to humans.

Which brings me back to that delineation I often stick to between invasive and introduced…

The reason I make such a case for identifying European starlings as introduced as opposed to invasive is clear: nature purists like to call things invasive because it alienates the species and washes away all human responsibility.  A good example is the rosy wolfsnail (a.k.a. cannibal snail; Euglandina rosea).  This predatory mollusk is among the top ten most destructive nonnative species around the globe.  Native to Texas, I rather enjoy watching them, but we humans intentionally introduced them all over the planet in hopes of having them control the East African land snail (a.k.a. giant African land snail; Achatina fulica), a destructive species we also had introduced all over the world.

Unfortunately for native snail species in all those places, the rosy wolfsnail not only went after the African snail, but they also went after all the native snails.  This resulted in the extinction of many native snails throughout the world.  It also resulted in the wolfsnail being named a major invasive species.  But it’s not an invasive species!  We introduced them intentionally and with forethought, but now calling them invasive makes us feel better about hating them for all the damage they’ve done.

And thus comes the crux of the matter: both invasive and introduced species do what they do because they evolved naturally to do those things, whether it be killing snails or out-competing native birds.  In the case of truly invasive species, they move into nonnative ranges of their own volition and fight to claim new territory and resources; in the case of introduced species, we put them in nonnative ranges and then act shocked when they run amok—at which point we start calling them invasive so we can hate them and destroy them without admitting we are the problem, not the species we’re so angry at.

So I reiterate what I said to Seabrooke: I wholeheartedly agree with her understanding and use of “invasive” and “introduced”.  However, I will continue to draw a line in the sand between the two terms.  There is a massive difference between the two in light of how people tend to use them and what people justify by way of them; so few nature purists realize the hypocrisy or cognitive dissonance they express by picking and choosing which invasive species should be hated and which introduced species should be considered invasive; calling something invasive stigmatizes a species in the public’s eye and misinforms lay people as to who precisely is responsible for the damage that species is doing; and very few seem to recognize or appreciate the laughable irony of having humans call any species invasive because it’s harming native flora and fauna.

It has begun

Less than four miles/six kilometers north of downtown Dallas.  Nestled within the hospital district with towering university and medical buildings quite literally a stone’s throw away.  Surrounded by major thoroughfares and the constant din of automobiles and airplanes.  A motte only 3.5 acres/1.4 hectares in size.  Yet at the height of summer, it will host more than 70 bird species.

A great egret (Ardea alba) standing on winter grass (2010_02_06_049479)

Some species will travel hundreds of miles from their usual nesting territories just to play a part in what can only be described as the most powerful and profound example of opportunism in the whole of North Texas.  Thousands of nests will be built, thousands of eggs will be incubated, thousands of chicks will be hatched, and from late winter through early autumn it will be a place of unimaginable beauty and awe such that all those who see it will be left struggling to comprehend how it could be real.  And all this will take place in a grove of trees much smaller than your local supermarket.

A black-crowned night-heron (Nycticorax nycticorax) perched on a branch (2009_06_20_024000)

I’m of course speaking about the colonial wading bird rookery that continues to thrive on the grounds of the University of Texas Southwestern Medical Center campus.  Older than the oldest records, all we know about the rookery is that it hosts a congregation of species so diverse and so vast that it engenders an otherworldly sense of reality, as though one has been transported to the most remote place imaginable where mystic creatures thrive.

A snowy egret (Egretta thula) hunting in the shallows (2009_06_01_021362)

Yet this is anything but remote.  The rookery lives in an urban jungle.  Six lanes of concrete surround it on two sides and multistory buildings and parking garages surround it on the other two.  Nevertheless they will come, the birds, and some will travel far outside their usual nesting territories just so they can join thousands of other pairs who will mate, nest, brood and rear young in a place that seems accidental at best.

A cattle egret (Bubulcus ibis) resting in a tree (2009_06_13_023406)

Already the largest nesters, the great egrets (Ardea alba), vie for prime real estate, these giant birds wandering the still barren woods plucking up twigs and sticks with which to build a home for their newest generation.  Soon the black-crowned night-herons (Nycticorax nycticorax), little blue herons (Egretta caerulea) and snowy egrets (Egretta thula) will join them.  Following quickly behind them will come the anhingas (a.k.a. water turkey or snakebird; Anhinga anhinga), the cattle egrets (Bubulcus ibis) and the tricolored herons (a.k.a. Louisiana heron; Egretta tricolor).  And when it all seems too much, white ibises (Eudocimus albus) will arrive.

A tricolored heron (a.k.a. Louisiana heron; Egretta tricolor) standing in a tree (2009_07_12_026569)

Meanwhile, flycatchers, cardinals, grackles, woodpeckers, kingbirds, mockingbirds, jays, swallows, wrens, hawks, thrashers, sparrows, robins and a legion vast of species will settle in where space is available.  Simultaneously the opossums and woodrats and raccoons and snakes and tree frogs and other animals will begin making appearances.  The air will fill with insects, the ground will move with crawling things, and the transformation will be complete: the rookery will once again be alive, will be thriving, will be full of so much life that it boggles the mind.

A white ibis (Eudocimus albus) looking out from the treetops (2009_07_12_026496)

I will make every effort to visit regularly and document reliably this most fascinating natural wonder.  As I did last year, I hope to follow the progress of the rookery and observe its inhabitants as much as possible.  I hope you’ll come along for this journey through the wonderland of an urban rookery where life abounds, where magic abides, and where city dwellers can lose themselves in nature’s demonstration of alien life.  One cannot say they know birds in North Texas without visiting this place, for this place holds more bird species and more individual birds per square yard/meter than anywhere else in this region.

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[1] Great egret (Ardea alba)

[2] Black-crowned night-heron (Nycticorax nycticorax)

[3] Snowy egret (Egretta thula)

[4] Cattle egret (Bubulcus ibis)

[5] Tricolored heron (a.k.a. Louisiana heron; Egretta tricolor)

[6] White ibis (Eudocimus albus)