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  • Writer's pictureAllan Sander

Costanera Sur Ecological Reserve - August

Updated: Feb 7

“Senior, adonde vas?” “Sie, Reserva Ecológica Costanera Sur.” We will see which entrance/road the taxi driver takes me; he takes Avenida Belgrano until it terminates at Avenida Dr. Tristan Achaval Rodriguez. “Perfecto! Gracias, senior!” “Senior? Entrada…” “Sie, Lo se. Es O.K, gracias!” This is basically the midway point between either entrance. I cross the street to reach the esplanade and I still get the sensation as if I am overlooking a moat. *There is some merit to this thought as before me is a huge landfill, its contents a result of the demolition of former buildings and roads from a past political reform project that went awry.

Wave after wave from the silt laden estuary of the Rio de Plata, reclaimed the land, and now this wall protects the reserve. Water lettuce (Pistia stratiotes) still engulfs a large percentage of the water’s surface, I thought there would be less growth, this being the winter season. The disturbance of a weed eater machine skimming large sheets of vegetation off the surface is merely a detour for the feeding coots, ducks,


and jacanas.

– it is just seen as another creature going through its daily routine.

The same reaction holds true for its land-based operators – dodging around the human activity along the boardwalk.

A handful of Monk Parakeets (Myopsitta monachus) land atop an intricately designed light pole, squabbling the entire time. The noisy dispute continues as they disembark across the water and head into the reserve. “I am right behind you guys!”

The opened gates of the Ingreso Brasil [Brazil Entry] has a cement walkway that leads to the Nature Center – not only does it enlighten you about the local flora and fauna, but there are toilets, a water fountain, along with a detailed map of the area. Before reaching that point, I veer off to the right up a staircase to another level, avoiding the crowds. I scatter a large flock of Saffron Finch (Sicalis flaveola) plus a Rufous Hornero (Furnarias rufus); it screams in protest letting me know whose territory this is.

Cement columns support metal railings along the periphery of this edifice. Crossing over, looking down I find an active watering hole. There are some patchy reedbeds, but mostly overgrown weeds. Partially submerged is a pile of leafless limbs, this appears to attract the most birds. Intermittent baths are relished by various finches, Creamy and Rufous-bellied Thrushes (Turdus amaurochalinus and rufiventris),

Rufous-naped Sparrow (Zonotrichia capensis),

and a Sayaca Tanager (Tangara sayaca).

Several Variable Orioles (Icterus pyrrhopterus) vaulted into the trees when I arrived but did not venture any closer during my stay.

After an hour of observing avian hygiene, it was time to move on. A pleasant “Sweet - trrrrrrrrr," rings out from a Straneck’s Flycatcher (Serphophaga griseicapilla), mirroring my sentiments perfectly.

I circle to the backside of the Nature Center where a wooden boardwalk cuts through the trees and opens up to a viewing platform; it overlooks a marsh at the southern end of Laguna de los patos (Duck Pond). On a prior visit the pantano had dried up allowing large swaths of the invasive Yellow Flag (Iris pseudacorus) to stake a claim. Again it appears to have no water, but it is actually obscured by floating vegetation.

A Limpkin (Aramus guaruana) is right at home as this, too, is prime habitat for its favorite food, the Apple Snail (Pomacea canaliculate).

The brown bodies of the local Coypu (Myocastor coypus) are the only other contours that break this color scheme of yellow-and-green.

Feeling something tapping the back of my head, I lean forward to turn around and realize I backed up into a bunch of Castor Bean plants (Ricinus communis), a native of East Africa. Swaying at the tops of stems are the green, spherical seed capsules that carry a bean that has one of the deadliest natural poisons known, called ricin.

This became a noteworthy distraction in regards that it allowed me to spot a Rufouscent Tiger Heron (Tigrisoma lineatum) through the wooden slats.

A German speaking family comes hopping into the scene. I point out the heron and they quiet down, enjoying the moment. Our feathered friend is so close that I fill the screen with features of its head and neck.

I am back on the Tegu Trail, my first pájaro encounter I find is poking its bill into a depression along the bank; it is a Buff-winged Cinclodes (Cinclodes fuscus).

Silhouetted against the sky between the patchwork of leafy boughs, fly several Neotropical cormorants. One must keep scanning at all levels for any type of movement or sound. A clearing in the canopy reveals another repeat of last year, a pair of Maguari Storks (Ciconia maguari). I overexpose my shots having forgotten to reset the compensation from the cormorant encounter. (Fortunately I have an image to show from a prior visit.). I do a lot of manual override for exposure compensation so, I must remind myself to, “Focus!”

Another scenic overlook gives a more panoramic view. The water is covered with vegetation, with a clear area further back that hosts an assortment of ducks and coots. Scattered in its heart are three Black-necked Swans (Cygnus melancorhyphus),

soon to be joined by a very energetic nutria.

A lone Limpkin searches for snails.

A hawk soars in, and as I am about to have a look with my bins, I see two birds perched out on the island, then another chases after its sibling? These are all immature birds; overall chocolate brown, same heavy mottling on the underside mixed with white. Also, topside, showing white at the base of the tail and one bird shows rufous in its shoulders.

It is a family of Harris’s Hawks (Parabuteo unicinctus). These birds of prey are unique -- hunting in unison like a pack of coyotes to enhance the odds of capturing its quarry.

Several birds would dive-bomb the limpkin with a mock stoop; as the assailant pulled up, you could hear its wings piercing through the air!

Back on the trail allows a brief encounter with a Golden-billed Saltator (Saltator aurantiirostris)

plus an open canopy view of both caracaras: Chimango and Crested (Phalcoboenus chimango & Caracara plancus).

Reaching another vantage point has more open water. This scene is so much more subdued. A conspicuous Southern Screamer (Chauna torquata) greets the morning with outstretched wings; its carpal spurs are quite evident.

Pairs of teals’ glide in: Silver and Speckled (Spatula versicolor / Anas flavirostris).

Along an island of stacked timbers patrols a handsome Tiger-heron (Tigrisoma lineatum).

In the open water, paddling alongside the water plants, is a Spot-flanked Gallinule (Gallinula melanops)!

Moving ahead, seed trees attract siskins, sparrows, and blackbirds. A Rufous-naped Sparrow (Zonotrichia capensis) breaks into song,

I move in for a pic and flush a woodcreeper? from below. I see movement but cannot get a clean look so I “pish” a few times for a reaction. It sneaks a peak, as do I, and abruptly drops from view. “Spinetail?” I try again, up it comes, I anxiously snap a shot. “Did I see a yellow throat?” A quick review on my screen and, “Yes!” It is more like a dollop of yellow paint starting from under the chin that is smeared down across its throat. Later research concluded it to be a Yellow-chinned Spinetail (Certhiaxis cinnamomeus), for me it is a “lifer,” in bird lingo.

Luck is on my side, a Gray-cowled Wood-rail (Aramides cojaneus) is heading in my direction. Rails are generally secretive birds, like the spinetail, and such behavior is referred to as “skulkers.” Basically, hunkering down to remain obscure under the cover of thick vegetation. Well this bird is cooperative, however there are plenty of branches, leaves and grass between the two of us. Still, a very colorful bird.

The descending call of a Narrow-billed Woodcreeper (Lepidocolaptes angustirostris) rings out as it flits from tree to tree.

This congregation also hails a quartet of Golden-crowned Warblers (Basileuterus culicivorus) making their way through the understory.

A beautiful Black-and-rufous Warbling-finch pops into view.

I turn skyward to locate the chipping notes of Hooded Sisikins.

In the crotch of the tree sits the mud nest of a hornero.

The traveling circus quickly moves on leaving a very sedate nutria munching away at the water’s edge. The brief raising of its head is like a nod of approval for the encore to commence - which has Nanday Conures (Aratinga nenday) falling from the sky under wings of green and blue.

I wait out a short burst of rain then head out to my last platform that oversees the north end of Coypu Pond. A territorial Kiskadee fends off any intruders. Coots, jacanas and pochards ply the waters below, as pigeons and caracaras transect the azure airways above.

Nearing the exit, actively feeding along a manicured lawn are horneros, a thrush, and mockingbirds. Blue-and-white Swallows swirl over the forest edge. Now outside and looking

back, a cormorant takes advantage of the last warming rays to dry its wings.

My last few shots capture feeding Coscoroba Swans (Coscoroba coscoroba),

a fleeting Cocoi Heron (Ardea cocoi).

and a tiger heron that occupies a spit of land which ironically points me in the right direction.

It is the next morning, I choose to cruise along the tree-lined glade for some different photo ops. It is hard not to miss this ramshackle assemblage of sticks high up in the trees; it is an ‘avian condo’ housing Monk Parakeets (Myopsitta monachus).

Several occupants drop down to feed. I scurry over to find them cracking open seeds off the spikelets of grass.

Picazuro Pigeons (Patagioenis picazuro)

swallow them whole using their muscular crop to crush them into a digestible mash.

Red-headed Cardinals (Paroaria coronata) have a thick, conical-shaped bill to break open seeds before it is consumed.

Hastily chasing down invertebrates between the blades of grass are Rufous Hornero (Furnarius rufus) and Cattle Tyrants.

“Alright, let us see what entertainment lies behind the wall!”

Act I: A White-tufted grebe (Rollandia Rolland) exercising its wing muscles before joining others underwater. Another bird stretches its legs, they are set so far up on the rear that they appear to protrude straight from the tail; hence, an early English nickname for these birds, arsefoot.

Act II: Diving pochards follow suit, arcing their bodies into the air before they take the plunge.

Act III: The feeding behavior of the swan is to simply lean forward and ‘tip up’ the rear end and allow that long neck to reach the succulent plants below the surface.

Act IV: It look as if a cormorant (Phalacrocorax brasilianus) wants all of the attention; it ‘whacks’ the water with such consternation you are afraid it might break a wing in the process!

I came up with three options for this concluding Act: - Subtle: "I always thought to bathe was a means of relaxation." - Astonished: “What a way to take a bath!” - Sarcastic: "Prepping to try out for a gig with ‘Angry Birds!’"

I would love to hear from you about any other quick-witted response that comes to mind.

Rounding out the scene with the more subdued ‘stand-ins:’ - a raft of sleeping Lake Ducks (Oxyura vittata).

- Brown-headed Gulls (Chroicocephalus maculipennis) lazily drift to the whims of the wind.

- among the reeds a family of Screamer (Chauna torquate) chicks huddle together.

My favorite is a turtle that has dragged itself out of the water with a miniature island of vegetation on its shell. What I see is a reenactment of a **Native American folktale of how the turtle created the earth!

There are arias aplenty as I walk through the open gates of the Ingresso Viamonte:




and mockingbirds.

I return to the Coypu Pond stage to find a Spot-flanked Gallinule gliding across the open water.

Back to the tree-lined trail, tapping sounds reveal a Checkered Woodpecker in search of sustenance.

A group of warblers, all Golden-crowned with one Parula, rustle about among the foliage. A pair of Masked Gnatcatchers jerkily move about with tails held high. This time the woodcreeper pulls up from the rear as the flock synchronizes a hasty departure.

At first what I thought of as an interesting mix was simply a coincidental overlap with a flock of Nanday Parakeets and Southern Lapwings crisscrossing in the air; both can make quite a racket, however.

A thunder roll drifts in from behind, I turn to see the build-up of dark clouds. Another distraction, two Wood-rails are foraging below on the shoulder of the drier Duck Pond. Stealthily I make my way down. One bird has trailed off to where I can only detect its movement by sound. The other continues to forage, at times glancing in my direction. Still, there is a lot of obstructions but I manage to capture the bright color scheme from its face down.

It has been interesting for me to have the good fortune of international travel, experiencing the natural world from nearly every continent. I bring this thought up as I encounter another clump of Calla Lilies (Calla aethiopia), a native to Southern African but found worldwide.

So many plants have been introduced outside their natural range. A major portion of the plants found in the reserve are non-native species. Still, the ingrain survival of species has flora and fauna adapt with change to maintain their reproductive success to thrive.

Open sunny areas along the road display the bright yellow inflorescence of dandelions (Taraxacum species), a European native that thrives on most continents. A Painted Lady butterfly (Vanessa cardui) finds it a good nectar source. This little beauty also has worldwide distribution but it is due to its own valiant efforts; a very strong flyer, tolerating colder temperatures, and will undertake long migrations where necessary.

A Mexican Silverspot (Euptoieta

hegasia) visits one of the flowering

shrubs, and

rounding out this refreshing palette of sunset-orange is an appearance from a Ridge-browed Carpenter Bee (Xylocopa frontalis).

A steady breeze is the added push to, “Make haste!” At a hurried pace I decide to have a last look behind the Nature Center.

Just before the boardwalk, I find Golden-billed Saltators (Saltator aurantiirostris) feeding on the open lawn.

There is very little to be found at the marsh, vegetation at every level, but nary a speck of water to be seen between the foliage. A tyrant (Machetornis rixosa) sallies up to nab insects from the air at ground (water) level

while a Straneck’s Flycatcher does the same above from a tree along the shore.

Otherwise, sitting dead center is the lord of its domain. its wet feathers are matted, looking jagged and horn-like, and with those piercing blood-red eyes, a persona that emotes, “I am a force not to be reckoned with!” Surprise! It is only a grebe that is just 29cm or 11 inches in length, and does not even weigh a pound, basically around 13 ounces! The rain begins – quite the curtain call, indeed.

Location: Costanera Sur Ecologica Reserva, Buenos Aires, Argentina

Date: August 2023


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