Parana River Delta and Costanera Sur, Buenos Aires, Argentina 2001-02

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Participants: Sergio Corbet


In and around Buenos Aires
with Sergio Corbet

Sergio Corbett leads wildlife and birdwatching tours around his native Argentina. Check this page for his regular bird reports or contact him if you're heading that way. Click here to see Sergio's entry in the Birders Address Book

Sergio CorbetCostanera Sur Nature Reserve - September 2002

On September 17th, at 8 a.m. I met a local birder with whom we had planned to look over every corner of the reserve so as not to miss a single species. During the morning the weather stood pleasant and there were very few people around, mainly due to a rainy forecast for the day. We found a couple of Southern Lapwings looking after their single chick, feeding very close to it. This year there are a tremendous number of Black-and-rufous Warbling-Finches, so abundant they are that they seem to outnumber the ever present Rufous-collared Sparrow.

Another bird seen very often on that day was the Vermilion Flycatcher always making a striking contrast with the surrounding vegetation. We made more than 20 different sightings of this bird! Several Chilean Swallows were circling above us seemingly in a farewell parade before leaving southwards to their Patagonian homeland. Newcomers such as White-rumped Swallows and Grey-breasted Martins appeared feeding profusely as the air was full of insects, something very typical before a storm or rainfall. I saw a lonely Wilson's Phalarope flying southwards and by late afternoon a couple of these were flying close and in front of a huge flock of Brown-hooded Gulls.

Sitting on top of some reeds a Scarlet-headed Blackbird gave us a display of its superb colours, a picture difficult to forget. We had a very, very close sighting of a Stripe-backed Bittern that must have thought that it was very well camouflaged in a bush and thus almost sat still and gave us all the time we wanted to look it over. A Long-winged Harrier as well as a Snail Kite flew by and we paid a visit to a nesting Southern Crested-Caracara only to see it feeding a mouse to a chick.

The always elusive tiny nature gem as is the Many-coloured Rush-Tyrant this time on three different occasions showed up jumping over some dead reeds giving us a full display of itself as never before. What a bird and how beautiful it's colours combine! By mid-day, very argentine style, we went to a nearby restaurant and had some steaks washed down with some red wine. It was curious to see on several occasions the Long-tailed Reed-Finches with their beaks full of straws flying into the bushes obviously making their nests. A lonely Glittering-bellied Emerald Hummingbird rushed past us to stop and feed on the flowers of a blooming bush. More often than ever before White-tipped Plant Cutters were seen at different places. The sighting of a Green-backed Saltator and several other rarities assured us of having spent one of the most fantastic birding days at the Reserve. At closing time at 6 p.m. we had counted 93 different bird species. Certainly we had set a new single day birds sighting record at the place and I added 6 new birds species to my Costanera Sur NR birds list:

Short-billed Canastero, Asthenes baeri.
Sharp-tailed Grass-Tyrant, Culicivora caudacuta.
Lesser Shrike Tyrant, Agriornis murina.
White-tipped Plant Cutter, Phytotoma rutila.
Green-winged Saltator, Saltator similis.
Red-rumped Warbling-Finch, Poospiza lateralis.

Costanera Sur Nature Reserve - June/July 2002

At last the closing date to my one year 'birding survey' at Costanera Sur has arrived. Right now the count comes up to 158 diferent birds species seen through a year. I certainly intend to keep on visiting the place, but now I will be looking for something outstanding, new or a vagrant!

The months of June and July proved to be very cold by our standards. We do not get any snow in Buenos Aires but the southeastern wind blowing from the Rio de La Plata makes one feel very miserable not to mention when the wind comes straight from the south, because that's an open door to Antarctica! The same must happen to the birds as most of them leave and fly northwards yet we are rewarded by Patagonian visitors that come up here to winter. So during June three of such southern visitors made themselves seen, the Lesser Canastero Asthenes pyrroleuca. Chilean Swallow, Tachycineta leucopyga Blue and White Swallow, Notiochelidon cyanoleuca.

By the very end of June several Black-necked Swans and also some Coots were busy getting their nests ready as well as some Picazuro Pigeons were seen gathering small branches to do the same. The month of July did not show much of a change with the previous one but this time I saw 4 new birds at the place and a vagrant: Ash-coloured Cuckoo, Coccyzus cinereus Common Miner, Geositta cunicularia Sooty-fronted Spinetail, Synallaxis frontalis Rufous-capped Spinetail Synallaxis ruficapilla.

By the very end of July the lengthning of the daytime started to be felt. Although the cold weather spell continued, many birds started to exercise their courting abbilities as did some male Shiny Cowbirds that were seen singing and trying to draw the attention of the females wearing their blue metal-coloured coat, a distitinctive local sign that Spring is not far away!

Another sight was provided by 4 Red-headed Blackbirds chasing probably out of their territory a clumsily flying Southern Caracara. Finally on my last visit, suddenly in one of the marshes the Coots and resting Gulls started a terrible noisy mess trying to elude the attacking dives that 4 Black-browed Albatrosses, Diomedea melanophys were taking at them. With my binocs I could see perfectly well how these giants doubling in size the Coots and Grey or Brown-headed Gulls would try and get with their open beaks a bite at the otherwise swimming birds. These Albatrosses are vagrants that come to our local port following incoming ships from tha Atlantic Ocean.

This one year survey gave a total of 158 bird species to be seen at Costanera Sur NR through the year. Any visiting birder will be able to see at any time of the year, birding in good weather during a whole day about 55 bird species, getting this number increased to about 80 species during the warmer months of local late Spring, Summer and early Autumn.

Costanera Sur Nature Reserve - April/May 2002

During April the most outstanding sights were a very large flock of Wattled Jacanas bunching together in a number of over 30 birds! Also about a dozen of Roseate Spoonbills kept together for several weeks until the changing cold weather must have driven them away more into the warmer climate in the country's north.

In the month of May the only new birds seen at the place were a very large bunch of Chestnut-capped Blackbirds, Agelaius ruficapillus that stayed for several weeks. I still have seen some of these on last week feeding on the Pampas Grass' panicles searching for the scarse seeds. I have seen several Picazuro Pigeons gathering small branches eventually to start building their nests. It would seem that it is still too early for this task, but Nature knows better.

Costanera Sur Nature Reserve - March 2002

At last I hit the 150 bird species mark at Costanera Sur! Although summer activity at the reserve didn't prove to be very intensive if we consider the arrival and sighting of new species, at the end of March after a long bad weather spell, on last Easter Sunday I went there and saw a couple of new birds that allowed me to round the 150 species mark! "This year the month of March proved to be unstable mainly in Buenos Aires and the bad and windy weather was a fairly common thing. When birding was possible I sneaked into the Costanera Sur Nature Reserve but to my grief with no results. Finally on the very last day of the month, March 31st the sky cleared, thanks to a strong western wind. During my usual walk I spotted a couple of birds that were new this Season to Costanera Sur: American Kestrel, Falco sparverius. and Short-billed Pipit, Anthus furcatus. And what a couple of birds they proved to be! Fall Season has started at last."

Costanera Sur Nature Reserve - January/February 2002

We are entering our last Summer fortnight before Fall and the temperatures are making themselves felt! Locally, last week we had temperature marks hitting around 38°C but this week looks a bit milder although very unstable. I rounded off February birding and although the number of birds seen during January and February was much lower than on previous months it still was rewarding. First of all, while birding in mid January, one day I saw several Rufous-collared sparrows feeding and among them I discovered a white bird behaving very naturally with the rest. A close look revealed an albino Rufous-collared sparrow! Where was my camera? Its legs were pink and almost translucid, the eyes were deep red and from time to time it would bring up its feathers on top of the head, the typical crest this species can show (click here for picture).

Some days later, while birding early in the morning with a visiting birder from Guernsey, just as we entered the Reserve by its northern entrance and managed to walk some metres we suddenly saw perching on a low branch of a nearby tree a couple of Plush-crested Jays feeding 2 well grown up chicks. They were feeding so close that binoculars were a nuisance, we managed to have a spectacular sight of them with our bare eyes! So now we may suppose that we have a new bird species established in the area of native tropical origins! If all goes well in a couple of years we'll have a little bunch of these very nice birds. While birding on February 12 I was surprised to see in the Reserve many or even too many Fork-tailed Flycatchers. They were feeding not so much on insects as they should do but they were gorging themselves with some small red berries that ripened on many bushes bordering the roads and trails. On several bushes I counted up to a dozen birds feeding at the same time! I could perfectly see that the Fork-tailed Flycatchers were making quite an effort to swallow the whole berries as their beaks would open just to let them go through. Flycatchers eating berries, something new to me! Competition was fierce mainly from the Kiskadees, Chalk-browed Mockingbirds, Rufous-bellied and Cream-bellied Thrushes.

Birds seen during the last two months of January and February:

American Anhinga, Anhinga anhinga.
Stripe-backed Bittern, Ixobrichus involucris.
Plumbeous Ibis, Harpiprion caerulescens.
Roseate Spoonbill, Ajaia ajaja.
Brazilian Duck, Amazonetta brasiliensis.
Black-headed Duck, Heteronetta atricapilla.
Long-winged Harrier, Circus buffoni.
Limpkin, Aramus guarauna.
Lesser Yellowlegs, Tringa flaviceps.
Suiriri Flycatcher, Suiriri suiriri.
Bar-winged Cinclodes, Cinclodes fuscus.
White-crested Tyrannulet, Serpophaga subcristata.
Tawny-crowned Pigmy-tyrant, Euscarthmus meloryphus.
Stripe-capped Sparrow, Aimophila strigiceps.

Fall is not far away, I believe that I'll see some more newcomers although fewer birds will be seen at the place. Now I have a total of 148 birds species seen during 7 months of continuous birding and still going.

Costanera Sur Nature Reserve - November/December 2001

November was still a month of unpredictable weather. On November 23rd a group of Swedish birders came along and we birded very well at Costanera Sur until around 3 o'clock in the afternoon. Then a tropical storm hit the place and soaked us through in minutes. These fellows had never experienced such a downpour and just couldn't react. The same happened to a group of newly arrived English birders that innocently came into the Reserve and were also soaked by the rain in minutes. Then it stopped raining abruptly the same way as it had started. But all the place was flooded so the birding day came to an end.

The month of December was much drier and warmer. The oncoming summer season was making itself known and felt. It kept on getting warmer right into the first week of January. So I birded again with several visiting birders on December 20th, 29th and 30th. Finally with an English visiting birder from Guernsey we birded on January 4th until a rain storm interrupted our afternoon birding.On that day we saw 65 different bird species, a good number!

New birds seen between November 23rd and January 4th, 2002.

Bare-faced Ibis, Phimosus infuscatus.
White-faced Ibis, Plegadis chihi.
Black-bellied Tree Duck, Dendrocygna autumnalis.
Southern Wigeon, Anas sibilatrix.
Peregrine Falcon, Falco peregrinus.
Gilded Hummingbird, Hylocharis chisura.
Ringed Kingfisher, Ceryle torquata.
Chequered Woodpecker, Picoides mixtus.
Curve-billed Reedhaunter, Limnornis curvirostris.
Hudson's Canastero, Asthenes hudsoni.
Freckle-breasted Thornbird, Phacellodomus striaticollis.
Small-billed Elaenia, Elaenia parvirostris.
Scrub Flycatcher, Sublegatus modestus.
Sooty Tyrannulet, Serpophaga nigricans.
Warbling Doradito, Pseudocolapterix flaviventris.
Bran-coloured Flycatcher, Myiophobus fasciatus.
Black-and-white Monjita, Xolmis dominicana.
Swainson's Flycatcher, Myiarchus swainsoni.
Streaked Flycatcher, Myiodynastes chrysocephalus.
Towny-headed Swallow, Alopochelidon fuscata.
Sayaca Tanager, Thraupis sayaca.
Glaucous-blue Grosbeak, Cyanoloxia glaucocaerulea.
Blue-black Grassquit, Volatinia jacarina.

Red-crested Cardinal

(click here for more images from Sergio's visits to Costanera Sur)
As you can see, quite an impressive number of new arrivals. The previous list finished with 111 birds seen since my starting date, so now we have a total of 134 different bird species seen. And I still have 7 months to go!

Ribera Norte Nature Reserve - November/December 2001

Although this particular Reserve is small in size, its emplacement means it hosts many species not seen to the south. Tomas Svensson, a young swedish student on a scholarship visiting Argentina, asked me if there was a place in or around Buenos Aires different to the Costanera Sur to do some birding. I told him about the Ribera Norte Nature Reserve. The Reserve is about 12 hectares (about 30 acres) and is 23 km to the north of Buenos Aires city on the shore of the Río de La Plata. It is lowland with vegetation that stretches from the Paraná Delta allowing insects, plants and birds to thrive abundantly. The place is humid and warmer than Costanera Sur.

We went there in mid November - trees were still with a few leaves so it allowed us to look and see birds with ease. The day was fresh with a southeastern wind blowing from the river and the sky was clear and blue. The morning turned out to be very good.

Birds seen at the Ribera Norte NR:

Neotropic Cormorant, Phalacrocorax olivaceus.
White-necked Heron, Ardea cocoi.
Great Egret, Egretta alba.
Snowy Egret, Egretta thula.
Speckled Teal, Anas flavirostris.
Brazilian Duck, Amazonetta brasiliensis.
Roadside Hawk, Buteo magnirostris.
Southern Caracara, Caracara plancus.
Chimango Caracara, Milvago chimango.
Giant Wood-rail, Aramides ypecaha.
Plumbeous Rail, Pardirallus sanguinolentus.
Southern Lapwing, Vanellus chilensis.
Wattled Jacana, Jacana jacana.
Picazuro Pigeon, Columba picazuro.
Eared Dove, Zenaida auriculata.
White-tipped Dove, Leptotila verrauxi.
Reddish-bellied Parakeet, Pyrrhura frontalis.
Monk Parakeet, Myiopsitta monachus.
Glittering-bellied Emerald, Chlorostilbon aureoventris.
Gilded Hummingbird, Hylocharis chrysura.
Green-barred Woodpecker, Colaptes melanochloros.
Rufous Hornero, Furnarius rufus.
Vermillon Flycatcher, Pyrocephalus rubinus.
Swainson's Flycatcher, Myiarchus swainsoni.
Great Kiskadee, Pytangus sulphuratus.
Tropical Kingbird, Tyrannus melancholicus.
White-rumped Swallow, Tacycineta leucorrhoa.
Grey-breasted Martin, Progne chalibea.
House Wren, Troglodytes aedon.
Masked Gnatcatcher, Poleoptila dumicola.
Rufous-bellied Thrush, Turdus rufiventris.
Creamy-bellied Thrush, Turdus amauorochalinus.
Chalk-browed Mockingbird, Mimus saturninus.
Correndera Pipit, Anthus correndera.
Masked Yellowthroat, Geothlypis aequinoctialis.
Sayaca Tanager, Thraupis sayaca.
Double-collared Seedeater, Sporophila caerulescens.
Saffron Finch, Sicalis flaveola.
Black-and-rufous Warbling-finch, Poospiza nigrorufa.
Red-rumped Warbling-finch, Poospiza lateralis.
Rufous-collared Sparrow, Zonotrichia capensis.
Shiny Cowbird, Molothrus bonariensis.
Bay-winged Cowbird, Molothrus badius.
Solitary Cacique, Cacicus solitarius.
Epulet Oriole, Icterus cayennensis.
Hooded Siskin, Carduellis magellanica.

For a morning birding excursion to see 46 different bird species is not bad at all! On January the 2nd. I went to the same place with a visiting Zoologist from Montana, USA. We also went there in the morning so as to take advantage of the fresh climatic conditions before the sun would be high and the heat would be felt. We had an excellent morning without any wind and the birding was superb. I saw some new bird species not seen on the previous birding visit:

Black-crowned Night Heron, Nycticorax nycticorax.
Blackish Rail, Pardirallus nigricans.
Ash-coloured Cuckoo, Coccyzus cinereus.
Yellow-billed Cuckoo, Coccizus americana.
Guira Cuckoo, Guira guira.
Chequered Woodpecker, Picoides mixtus.
Narrow-billed Woodcreeper, Lepidocolaptes angustirostris.
Sooty Tyrannulet, Serpophaga nigricans.
White-bellied Tyrannulet, Serpophaga s. munda.
Pied Water Tyrant, Fluvicola pica.
Red-eyed Vireo, Vireo olivaceus.
White-lined Tanager, Tachyphonus rufus.
Yellow-billed Cardinal, Paroaria capitata.

Many birds were feeding their chicks or even nesting. So the activity was quite intense in the marshes, thickets and bushes. Most of the birds seen on the first birding visit were seen again so I added to that list just another 13 newcomers, while many of the birds were new to John Carlson, my birding partner on that day. We had previouly birded with him at Costanera Sur and here at Ribera Norte what struck him most was the silence that allowed to listen to the birds sounds and also feel the humidity caused by the nearflowing river and subtropical vegetation. A nice birding place to take into consideration when visiting Buenos Aires with time to visit both Reserves.

Costanera Sur Nature Reserve - October 2001

The second half of September and most of October were months that shall not be forgotten so easily by local birders. This year, Spring in our area decided to be as uncertain as ever, mainly with a very unstable weather that changed sometimes daily and sometimes kept wind and rain storms raging for days. The mess was so important that even the Pampas have felt it, farmers postponing sowings of corn and sunflower as well as suffering from floods in many prime farming areas. I suppose that such extreme bad weather must have had some consequences on birds nesting and hatching. Yet some fine weather will help birds start a new breeding season and make for a second nesting attempt. Summer is starting in a month and Fall is still very far away (end of March), so I think birds will have time to catch up rearing a new brood.

The following is a list of birds seen on September 21 at Costanera Sur:

Rufescent Tiger Heron, Tigrisoma lineatum.
White-necked Heron, Ardea cocoi.
Canada Goose, Branta canadensis.
Snail Kite, Rosthramus sociabilis.
Plumbeous Rail, Pardiarallus sanguinolentus.
Glittering-bellied Emerald, Chlorostilbon aureoventris.
Sulphur-bearded Spinetail, Cranioleuca sulphurifera.
White-bellied Tyrannulet, Serpophaga griseiceps.
Masked Yellow-throat, Geothlypis aequinoctialis.
Saffron Finch
Sicalis flaveola.
Long-tailed Reed-finch, Donacospiza albifrons.

When weather allowed and before being chased away by the rain, I did some birding on September 27th, October 16th and November 1st.

Here is a list of the new birds seen:
Whistling Heron, Syrigma sibilatrix.
Grey-necked Wood-rail, Aramides cajanea.
South American Stilt, Himanthopus mexicanus.
Grey-hooded Gull, Larus cirrocephalus.
Snowy-crowned Tern, Sterna trudeaui.
Narrow-billed Woodcreeper, Lepidocolaptes angustirostris.
Yellow-chinned Spinetail, Certhiaxis cinnamomea.
Many-coloured Rush-tyrant
, Tachuris rubigastra.
Tropical Kingbird, Tyrannus melancholicus.
Pied Water-tyrant, Fluvicola pica.
Fork-tailed Flycatcher, Tyrannus savanna.
Plush-crested Jay, Cyanocorax chrysops.
Grey-breasted Martin
, Progne chalibea.
Correndera Pipit, Anthus correndera.
White-browed Blackbird, Sturnella superciliaris.

bird photo - Chalk-browed Mockingbird
(click here for more images from Sergio's visits to Costanera Sur)

So now we have a list of 111 different bird species seen at Costanera Sur NR since since August 5th! Two of the afore mentioned species must be escapees. The first one is the "Canada Goose" that must have flown out of the local City Zoo on an "inspection" of better places to live at. The other one was the "Plush-crested Jay". Normally these birds are inhabitants of more northern subtropical parts of Argerntina. There were two of them seen only once on October 16th and then no more of them has been heard or seen."

Costanera Sur Nature Reserve - September 2001

Taking advantage of a visiting swedish birder, last Saturday (September 15th) we went to the "Costanera Sur Nature Reserve" for a whole birding day. Climatic conditions were rather cold, with a strong SW wind blowing up to 80 km p.h. with the sun shining between fast moving low clouds that on several times sprinkled us with tiny hail and rain. Fortunately there were birds everywhere, so we had an excellent birding day.

The Black-necked swans with their chicks I saw 3 weeks ago had now 5 chicks about the size of a teal. Several other couples of Black-necked swans as well as Coscorobas were swimming slowly surrounded by different sized chicks. A female Black-necked Swan was seen carrying one of its offsprings on its back with a second one trying to climb and join its brother, but failed as the chicks had a good size and there was not enough room for two. Many new birds have arrived, we saw a small bunch of Wilson's Phalaropes moving towards the south gently flying not very far from us. These early migrators were moving casually as if they were looking for a place to land at and take a rest, yet on they went and soon disappeared. The magnificent sight of a Scarlet-headed blackbird flying above the sunlit green reeds and then landing among them was the days' bird sight.

(click here for more images from Sergio's visit to Costanera Sur)

All in all we saw 68 different birds species on that day and I added to this particular place (Costanera Sur Natural Reserve) another 18 new birds species to be added to my previous lists in the Reports concerning this place.

Here are the names of the birds seen:

Striated Heron, Butiroides striatus
Black-crowned Night Heron, Nycticorax nycticorax
Red Shoveller, Anas platalea
Rosy-billed Pochard, Netta peposaca
Masked Duck, Oxyura dominica
Wilson's Phalarope, Phalaropus tricolor
Band-tailed Gull
, Larus belcheri
Wren-like Rushbird, Phleocryptes melanops
Vermillon Flycatcher
, Pyrocephalus rubinus
Dark-faced ground Tyrant, Muscisaxicola macloviana
Yellow-browed Tyrant, Satrapa icterophrys
Great Kiskadee, Pitangus sulphuratus
White-banded Mockingbird, Mimus triurus
European Starling, Sturnus vulgaris
Red-crested Cardinal, Paroaria coronata
Rusty-collared Seedeater, Sporophila collaris
Black-capped Warbling-finch, Poospiza cinerea
Scarlet-headed Blackbird, Amblyramphus holosericeus

So now the number of the different birds species seen here as from August 5 goes up to 85! This number will increase as we near the Summer season.

The Pampa Fields and Costanera Sur Nature Reserve - August 2001

During mid-August I went out into the Pampa fields. Weather conditions were good, with a clear sky with a soft northern breeze blowing. (In the southern hemisphere northern winds are warm and humid while south and southwestern winds are cold and usually dry).
I thought that I would find evidence of breeding behaviour and activity in most field birds because of the mild weather, yet this was only to be seen with waterfowl like coots and gallinules chasing one another and some wild ducks bunching around several scarce females.

At a distance. I could hear the "bzzzeee, bzzee, bzzee, bzee, bze" made by several Common Snipe Gallinago g. paraguaiae - several males were flying overhead and making their maddening and impressive dives to ground sitting females. From a distance they looked like jet fighters diving and strafing some ground targets. A really impressive sight indeed!

As we approach the end of August, with each day getting a bit warmer and longer, larger numbers of White-rumped Swallows have appeared flying all over Buenos Aires. Early in the morning, Rufous-bellied Thrushes have started to sing (whistle) and after sunrise the House Wren males as well as the Rufous-collared Sparrows join in.

August 26th, I decided to pay a visit to the city "Costanera Sur Nature Reserve". Did I get a reward! Not only did I see several new birds on this day but also I saw several Coscoroba coscoroba as well as some Black-necked Swans swimming with their newly hatched chicks! These resembled small grey-feathered balls with black eyes and bills swimming obedientely in front of or beside their parents that on several occasions chased away opening their beaks and making menacing swings at some Neotropic Cormorants that obliging cleared the way. At the side of a road, a small bunch of around 12 Yellow-winged Blackbirds were perching on dead and dry Pampa grass flowers catching insects and the males singing frequently. A small noisy flock of Black-hooded Parakeets came by and a couple of Gnatcatchers were busy chasing one another. So Spring is here.

Finally, before leaving the place, I saw a lonely Silvery Grebe which showed me its white silvery breast and belly while standing on its feet and beating its wings clearing some water after making a dive.

New birds seen in August:
Silvery Grebe Podiceps occipitalis
Great Grebe Podiceps major
Fulvous Tree-duck Dendrocygna bicolor
White-faced Tree-duck Dendrocygna viduata
Lake Duck Oxyura vittata
Giant Wood-rail Aramides ypecaha
Black-hooded Parakeet Nandayus nenday
Straight-billed Reedhaunter Limnoctites rectirostris
Yellow-billed Cardinal Paroaria capitata

Costanera Sur Nature Reserve - August 2001

After a cold Antarctic climate spell, suddenly a hot and humid air wave from southern Amazonia invaded eastern Argentina bringing a temporary relief to all of us. Temperatures rose above the 30°C mark and there was a definite Spring mood. Fortunately this did not last more than about 4 to 5 days, so plants and birds did not get really fooled enough so as to start their spring fuss with later colds bringing disaster. Taking advantage of the fine weather conditions, last Sunday I decided to do some birding at the Costanera Sur Natural Reserve. This Reserve, about 123 acres big, is at the southern Buenos Aires city border, reaching the River Plate banks. On that day the temperature mark reached 26°C and there was a small northwestern breeze.

That day the general picture and birds behaviour was that of a normal winter day, yet a few of them did depart from this. On first instance there was a big bunch of White-rumped Swallows, unusual in this place at this time of the year, flying low chasing insects. At different places several House Wren males where exercising their songs and so did a few male Rufous-collared Sparrows. Male Siskins were not in a singing mood yet male Chalk-browed Mockingbirds did sing a lot as they always do in Winter. When nearing the exit gate of the Reserve, a male Great Pampa Finch was tuning up a farewell song. So these scarse behaviours were the only evidences of a faint Springtime activity triggered off by this sudden brazilian hot air rush which I'm sure didn't last long enough because on the next day (monday) the temperature marks fell below the 10°C and the weather forecast was for even lower temperatures and rains to come.

While walking through the Reserve and looking at the many different birds, the complete list of the species I saw on that Sunday afternoon counted up to 58, a very nice number indeed! Considering that it was a Sunday afternoon when many people visit the Reserve even in Winter as is the season we have now, I find the number of different birds seen as amazing.

Least Grebe, Tachybaptes dominicus
Pied-billed Grebe, Podolymbus podiceps
White-tufted Grebe
, Podiceps rolland
Neotropic Cormorant, Phalacrocorax magellanicus
Great Egret, Egretta alba
Snowy Egret, Egretta thula
Cattle Egret
, Bubulcus ibis
Southern Screamer, Chauna torquata
Coscoroba, Coscoroba coscoroba
Black-necked Swan, Cygnus melancoryphus
Speckled Teal, Anas flavirostris
Brown Pintail, Anas georgica
Silver Teal, Anas versicolor
Roadside Hawk, Buteo magnirostris
Southern Caracara, Caracara plancus
Chimango Caracara, Milvago chimango
Spot-flanked Gallinule, Gallinula melanops
Common Moorhen, Gallinula chloropus
Red-gartered Coot, Fulica armillata
White-winged Coot, Fulica leucoptela
Red-fronted Coot, Fulica rubifrons
Southern Lapwing, Vanellus chilensis
Wattled Jacana, Jacana jacana
Kelp Gull
, Larus dominicanus
Franklin's Gull, Larus pipixcan
Brown-hooded Gull, Larus maculipennis
Rock Dove, Columba livia
Picazuro Pigeon, Columba picazuro
Eared Dove, Zenaida auriculata
Picui Ground-dove, Columbina picui
White-tipped Dove, Leptotila verreauxi
Monk Parakeet
, Myiopsitta monachus
Canary-winged Parakeet, Brotogeris versicolorus
Guira Cuckoo, Guira guira
Green Kingfisher, Chloroceryle americana
Green-barred Woodpecker, Colaptes melanochloros
Field Flicker, Colaptes campestris
Rufous Hornero, Furnarius rufus
Spectacled Tyrant, Hymenops perspicillata
Cattle Tyrant, Machetornis rixosus
White-rumped Swallow, Tacycineta leucorrhoa
House Wren, Troglodytes aedon
Masked Gnatcatcher, Polioptila dumicola
Rufous-bellied Thrush, Turdus rufiventris
Cream-bellied Thrush, Turdus amaurochalinus
Chalk-browed Mocking bird, Mimus saturninus
Rufous-collared Sparrow, Zonotrichia capensis
Double-collared Seedeater, Sporophila caerulescens
Great Pampa Finch, Embernagra platensis
Grassland Yellowfinch, Sicalis luteola
Black and rufous Warbling-finch, Poospiza nigrorufa
Shiny Cowbird, Molothrus bonariensis
Screaming Cowbird
, Molothrus rufoaxillaris
Bay-winged Cowbird, Molothrus badius
Yellow-winged Blackbird, Agelaius thilius
Epaulet Oriole
, Icterus cayennensis
Hooded Siskin, Carduelis magellanica
House Sparrow, Passer domesticus

The Parana River Delta, Buenos Aires - July 2001

Some 30 kms to the north of the city of Buenos Aires, lies Tigre. Today, this town belongs to the suburbs of the former mentioned city. It is also situated at the very southernmost tip of the Parana river delta. From Tigre motor boats depart daily to carry people to and from the islands within the delta where they live or work. The habitat is lowland marsh surrounded by native bushy vegetation. The farther you travel away from Tigre, the less populated it is and obviously the more birds are to be found.

During a 4 hour trip to the Paraná river delta on the 7th July 2001, the mosquitoes and the menace of a rain storm impacted severely on my birding quest. Yet I did manage to see a good selection of different birds species. Climatic conditions, being our winter, were humid.

Great Grebe Podiceps major
Olivaceous Cormorant Phalacrocorax olivaceus
Striated Heron Butorides striatus
Roadside Hawk Buteo flavirostris
Kelp Gull Larus dominicanus
Brown-hooded Gull Larus maculipennis
Picazuro Pigeon Columba picazuro
Eared Dove Zenaida auriculata
Green-barred Woodpecker Colaptes melanochlorus
Red-billed Scythebill Campylorhampus trochilirostris
Rufous Hornero Furnarius rufus
Cattle Tyrant Machetornis rixosus
Great Kiskadee Pitangus sulfuratus
Creamy-bellied Gnatcatcher Polioptila lactea
Rufous-bellied Thrush Turdus rufiventris
Diademed Tanager Stephanophorus diadematus
Solitary Cacique Cacicus solitarius
Epaulet Oriole Icterius cayennensis
Hooded Siskin Carduelis magellanica

rufous hornero picture

The Diademed Tanager was a great surprise, because these birds in the past years have almost vanished from these islands, mainly due to trappers and a decay in fruit bearing trees like plums and peaches that make part of their diet.

The Creamy-bellied Gnatcatcher did give me a very generous chance to look at it from a very short distance. I wonder which of us was more surprised by the encounter? This tiny bird is more common in the north-eastern part of the country, yet the global climatic warming up that we are living through must have helped this bird to move southwards along the bushy galleries along the Paraná and Uruguay river shores.

There was very little birdsong heard on that particular afternoon - except for the male Siskin ! The Solitary Cacique, a male, greeted me with several whistling and gurgling notes and then decided to move on into the bushes.