News - April 2015

censo

Polydamas Swallowtail Caterpillar
Battus polydamas
Borde de oro/Polydamas Swallowtail © Dolores Fernández

American Kestrel
Falco sparverius
American Kestrel
30-04-15 © Claudia y Diego Bastías

Buff-winged Cinclodes
Cinclodes fuscus
30-04-15 © Claudia y Diego Bastías

On the last day of April Diego Bastías, Walter and Manuel saw a male Red-crested Finch
Coryphospingus cucullatus, a female Hepatic Tanager
Piranga flava and a Chotoy Spinetail
Schoeniophylax phryganophilus

Yellow-browed Tyrant
Satrapa icterophrys
Yellow-browed Tyrant
18-04-15 © Mario Martín Chimento
Limpkin
Aramus guarauna
Limpkin
16-04-15 © José Alberto Lell
Cocoi Heron
Ardea cocoi
Cocoi Heron
25-04-15 © Mario Martín Chimento
Blue-and-yellow Tanager
Pipraeidea bonariensis
Blue-and-yellow Tanager
18-04-15 © Mario Martín Chimento

With bugweed fruit

Chimango Caracara
Milvago chimango
Chimango Caracara
18-04-15 © Mario Martín Chimento
Spot-flanked Gallinule
Gallinula melanops
Spot-flanked Gallinule
28-04-15 © Claudia y Diego Bastías
Nenday Parakeet
Aratinga nenday
Nenday Parakeet
27-04-15 © Claudia y Diego Bastías

Foraging on the lawn

Checkered Woodpecker
Veniliornis mixtus
Checkered Woodpecker
18-04-15 © Mario Martín Chimento
Red-crested Cardinal
Paroaria coronata
Red-crested Cardinal
25-04-15 © Mario Martín Chimento

More butterflies and moths
White-striped Longtail
Chioides catillus
Coluda de triángulo/White-striped Longtail© Claudia y Diego Bastías
Polydamas Swallowtail
Battus polydamas
Borde de oro/Polydamas Swallowtail© Hugo Aguilar
Common White-milk
Tatochila autodice
Lechera común/Common White-milk© Dolores Fernández
Common White-milk
Tatochila autodice
Lechera común/Common White-milk© Hugo Aguilar
Juno Silverspot
Dione juno
Juno/Juno Silverspot© Ezequiel Núñez Bustos
Juno Silverspot
Dione juno
Juno/Juno Silverspot© Mario Chimenti
Common Lazy
Actinote pellenea
Perezosa común/Common Lazy© Hugo Aguilar
Southern Fritillary
Euptoieta hortensia
Hortensia/Southern Fritillary© Hugo Aguilar

Rhyncopyga meisteri
Rhyncopyga meisteri© Victoria Mansilla
Velvetbean Moth
Anticarsia gemmatalis
Isoca de las leguminosas/Velvetbean Moth© Sergio Cusano

Sapium haematospermum
Curupí/Sapium haematospermum© Sergio Cusano
These protuberances are common on
Sapium haematospermum's leaves. They are called galls and are originated by a homopteran. These structures present tissue enlargement and they are hollow. The insect lays eggs and the larvae develop in the inside using the structure as a shelter.
In the photo some of the galls appear isolated and the leaf is barely modified. But when there are too many the leaf is twisted and deformed. They are green at the beginning and then turn reddish or red. Let's not confuse them with the fruit of this tree which are also look like red "small balls" CR
Some flowers and fruits
Wild Pea
Vigna adenantha
Poroto de río/Wild Pea© Sergio Cusano
Red wing
Heteropteris angustifolia
Mariposa/Red wing© Sergio Cusano
Balloon vine
Cardiospermum grandiflorum
Globito cipó/Balloon vine© Sergio Cusano
Balloon vine
Cardiospermum grandiflorum
Globito cipó/Balloon vine© Sergio Cusano
Mirlinton
Sechium edule
Papa del aire/Mirlinton© Sergio Cusano
Blue anise sage
Salvia guaranítica
Salvia azul/Blue anise sageViolet variety
© Sergio Cusano
Giant arrowhead
Sagittaria montevidensis
Sagitaria/Giant arrowhead© Sergio Cusano
Silk floss tree
Chorisia speciosa
Palo borracho/Silk floss tree© Sergio Cusano
New butterfly species: Ethologus Skipper
Nastra ethologus
Duendecillo de oro/Ethologus Skipper© Ezequiel Núñez Bustos
Duendecillo de oro/Ethologus Skipper© Ezequiel Núñez Bustos
Though its area of ditribution is the northeast of Argentina, this butterfly is considered to have a broader distribution. Its small size and colouring contributes to its passing unnoticed. Almost nothing is known about this butterfly. There is one record from Martín García Island, another from Punta Lara and this one from the reserve.

Gray-hooded Gull
Chroicocephalus cirrocephalus
Gray-hooded Gull
25-04-15 © J. Simón Tagtachian

The lower gulls are brown-hooded gulls

Many-colored Rush Tyrant
Tachuris rubrigastra
Many-colored Rush Tyrant
21-04-15 © Hugo Aguilar
Sayaca Tanager
Thraupis sayaca
Sayaca Tanager
09-04-15 © Hugo Aguilar
Wren-like Rushbird
Phleocryptes melanops
Wren-like Rushbird
09-04-15 © Hugo Aguilar
White-tipped Plantcutter
Phytotoma rutila
White-tipped Plantcutter
25-04-15 © J. Simón Tagtachian

The three white egrets at Coypu Pond
Cattle Egret
Bubulcus ibis
Cattle Egret
25-04-15 © Cora Rimoldi
Snowy Egret
Egretta thula
Snowy Egret
24-04-15 © Nicolás Giorgio
Great Egret
Ardea alba
Great Egret
17-04-15 © Hugo Aguilar

Yellow-chinned Spinetail
Certhiaxis cinnamomeus
Yellow-chinned Spinetail
25-04-15 © Dolores Fernández
Campo Flicker
Colaptes campestris
Campo Flicker
25-04-15 © J. Simón Tagtachian
Blue-and-white Swallow
Pygochelidon cyanoleuca
Blue-and-white Swallow
25-04-15 © J. Simón Tagtachian
Bare-faced Ibis
Phimosus infuscatus
Bare-faced Ibis
25-04-15 © J. Simón Tagtachian
Bare-faced Ibis
25-04-15 © J. Simón Tagtachian
White-faced Whistling-Duck
Dendrocygna viduata
White-faced Whistling-Duck
09-04-15 © Hugo Aguilar

Fight between white-faced whistling-ducks

Black-capped Warbling-Finch
Poospiza melanoleuca
Black-capped Warbling-Finch
25-04-15 © J. Simón Tagtachian
Variable Oriole
Icterus pyrrhopterus
Variable Oriole
09-04-15 © Hugo Aguilar
White-crested Tyrannulet
Serpophaga subcristata
White-crested Tyrannulet
21-04-15 © Hugo Aguilar
Golden-crowned Warbler
Basileuterus culicivorus
Golden-crowned Warbler
21-04-15 © Hugo Aguilar
Roadside Hawk
Rupornis magnirostris
Roadside Hawk
25-04-15 © J. Simón Tagtachian

Lost and found
Rescate/Rescue Rescate/Rescue
Rescate/Rescue Rescate/Rescue
Rescate/Rescue Rescate/Rescue
On Friday, 24th the Reserve was closed to look for a young man reported lost. Luckily he was found safe and sound. Both the personnel of the reserve, Policía Federal, Bomberos, Defensa Civil and Prefectura were involved in the search.
Photos © Nicolás Giorgio

White-tipped Plantcutter
Phytotoma rutila
White-tipped Plantcutter
24-04-15 © Claudia y Diego Bastías
Black-headed Duck
Heteronetta atricapilla
Black-headed Duck
23-04-15 © Claudia y Diego Bastías
Chimango Caracara
Milvago chimango
Chimango Caracara
23-04-15 © Claudia y Diego Bastías
Rock Pigeon
Columba livia
Rock Pigeon
21-04-15 © J. Simón Tagtachian

Large diving beetle
Megadytes giganteus
Large diving beetle
18-04-15 © Sergio Cusano
This beetle belongs into the family Dytiscidae, which are all aquatic. They spend their biological cycle in aquatic environments and are carnivores. Its body is hidrodinamyc and it has got hairs on its rear legs to swim more efficiently. They keep the air underneath their elytra, which are the hardened forewings which function like a case for the hindwings. When they need to get more air they go up to the surface exposing their rear part first. Though they are aquatic their wings are fully developed and can fly very well.

Golden Silk Orbweaver
Trichonephila clavipes
Golden Silk Orbweaver
04-04-15 © Claudia y Tito Di Mauro
Golden Silk Orbweaver
04-04-15 © Sergio Cusano
Cicada
Dorisiana drewseni
Cicada
09-04-15 © Sergio Cusano
Camuati Wasp
Polybia scutellaris
Camuati Wasp
21-03-15 © Victoria Mansilla
Paper wasp
Polistes sp.
Paper wasp
21-03-15 © Victoria Mansilla
Hoverfly
Palpada sp
Hoverfly
04-01-15 © Flor A Modeo
Cucurbit beetle
Diabrotica speciosa
Cucurbit beetle
04-04-15 © Victoria Mansilla
At wild peaVigna adenantha

White Peacock
Anartia jatrophae
Cenicienta/White Peacock© J. Simón Tagtachian Cenicienta/White Peacock© J. Simón Tagtachian

Limpkin
Aramus guarauna
04-04-15 © Claudia y Tito Di Mauro

Southern Screamer
Chauna torquata
Southern Screamer
21-04-15 © J. Simón Tagtachian
Southern Screamer
21-04-15 © J. Simón Tagtachian
Yellow-chinned Spinetail
Certhiaxis cinnamomeus
Yellow-chinned Spinetail
21-04-15 © J. Simón Tagtachian
Yellow-chinned Spinetail
21-04-15 © J. Simón Tagtachian
Warbling Doradito
Pseudocolopteryx flaviventris
Warbling Doradito
21-04-15 © J. Simón Tagtachian
Warbling Doradito
21-04-15 © J. Simón Tagtachian
Warbling Doradito
21-04-15 © J. Simón Tagtachian

Coypu
Myocastor coypus
Coipo/Coypu© Nicolás Giorgio
Coipo/Coypu © J. Simón Tagtachian

Least Grebe
Tachybaptus dominicus
Least Grebe
18-04-15 © Sergio Cusano
Yellow-billed Cardinal
Paroaria capitata
Yellow-billed Cardinal
21-04-15 © J. Simón Tagtachian
Unicolored Blackbird
Agelasticus cyanopus
Unicolored Blackbird
21-04-15 © J. Simón Tagtachian
Hooded Siskin
Spinus magellanicus
Hooded Siskin
21-04-15 © Nicolás Giorgio
Hooded Siskin
21-04-15 © Nicolás Giorgio
Rufous Hornero
Furnarius rufus
Rufous Hornero
22-04-15 © J. Simón Tagtachian
Rufous Hornero
22-04-15 © J. Simón Tagtachian
Fawn-breasted Tanager
Pipraeidea melanonota
Fawn-breasted Tanager
20-04-15 © Claudia y Diego Bastías
White-tipped Plantcutter
Phytotoma rutila
White-tipped Plantcutter
20-04-15 © Claudia y Diego Bastías
White-tipped Dove
Leptotila verreauxi
White-tipped Dove
17-04-15 © Claudia y Diego Bastías
White-browed Blackbird
Sturnella superciliaris
White-browed Blackbird
18-04-15 © J. Simón Tagtachian
Tropical Parula
Setophaga pitiayumi
Tropical Parula
18-04-15 © J. Simón Tagtachian
Ultramarine Grosbeak
Cyanoloxia brissonii
Ultramarine Grosbeak
18-04-15 © J. Simón Tagtachian
White-banded Mockingbird
Mimus triurus
White-banded Mockingbird
04-04-15 © J. Simón Tagtachian

New access at Viamonte nueva Via5 SAC 4 15 nueva Via4 SAC 4 15 nueva Via3 SAC 4 15 nueva Via SAC 4 15 nueva Via2 SAC 4 15 nueva Via1 SAC 4 15
The new access at Viamonte is already open to visitors
© Sergio Cusano
Works obras SAC 4 15Ditch to lay the cable for the bomb © Sergio Cusano

Limpkin
Aramus guarauna
19-04-15 © Cora Rimoldi
We looked for the bird vocalizing. It was this young limpkin calling

Thick-tailed Opossum
Lutreolina crassicaudata
© J. Simón Tagtachian

Scarlet-headed Blackbird
Amblyramphus holosericeus
Scarlet-headed Blackbird
17-04-15 © Hugo Aguilar
Scarlet-headed Blackbird
18-04-15 © Hugo Aguilar

Parasitism: Rosy-billed Pochard - Fulvous Whistling-duck
Rosy-billed Pochard
Netta peposaca
Rosy-billed Pochard
25-02-15 © Claudia y Diego Bastías

In this pochard family there are two fulvous whistling-duck chicks. The Fulvous Whistling-Duck may dump eggs in other birds' nests of its same species or not. This is not the first time we witness this event. There is a previous record of December 2009. On that occasion also a Rosy-billed Pochard was seen with a Fulvous Whistling-Duck chick among her ducklings.

Rosy-billed Pochard
09-03-15 © Claudia y Diego Bastías

Another pochard family parasitized by fulvous whistling-duck

Rosy-billed Pochard
29-03-15 © Carlos González Ledo

Two juveniles, a rosy-billed pochard, the one leading and a fulvous whistling-duck behind

Rosy-billed Pochard
08-04-15 © Claudia y Tito Di Mauro
Rosy-billed Pochard
08-04-15 © Claudia y Tito Di Mauro

Rosy-billed Pochard
Netta peposaca
Rosy-billed Pochard
03-01-15 © Carlos González Ledo

Several young male rosy-billed pochards can be seen in the pond. If one pays attention we'll see they are in different stages to become male adults. The bill is rosier and the head and neck are darker. And this individual has a wounded wing.

Rosy-billed Pochard
18-04-15 © Sergio Cusano

The injured picazo along with a male cinnamon teal

Rosy-billed Pochard
15-04-15 © J. Simón Tagtachian

Here with a female rosy-billed pochard. After months an a half it seems that the injured wing is not an issue to survive

Red Shoveler
Anas platalea
Red Shoveler
18-04-15 © Sergio Cusano
Red Shoveler
18-04-15 © Diego Carús
Red Shoveler
18-04-15 © Diego Carús
Buff-winged Cinclodes
Cinclodes fuscus
Buff-winged Cinclodes
18-04-15 © Diego Carús
Yellow-chevroned Parakeet
Brotogeris chiriri
Yellow-chevroned Parakeet
18-04-15 © Sergio Cusano
Yellow-browed Tyrant
Satrapa icterophrys
Yellow-browed Tyrant
18-04-15 © Diego Carús
Cinnamon Teal
Anas cyanoptera
Cinnamon Teal
18-04-15 © Sergio Cusano

With yellos-billed teals

Unicolored Blackbird
Agelasticus cyanopus
Unicolored Blackbird
04-04-15 © Sergio Cusano
Rufescent Tiger-Heron
Tigrisoma lineatum
Rufescent Tiger-Heron
14-04-15 © Claudia y Diego Bastías
Eared Dove
Zenaida auriculata
Eared Dove
18-04-15 © Sergio Cusano
Shiny Cowbird
Molothrus bonariensis
Shiny Cowbird
18-04-15 © Sergio Cusano
Cattle Egret
Bubulcus ibis
Cattle Egret
17-04-15 © Claudia y Diego Bastías
Scarlet-headed Blackbird
Amblyramphus holosericeus
Scarlet-headed Blackbird
17-04-15 © Claudia y Diego Bastías
Scarlet-headed Blackbird
Amblyramphus holosericeus
17-04-15 © Claudia y Diego Bastías
New moth: Bagworm
Oiketicus platensis
Bicho canasto/Bagworm© Sergio Cusano
The bagworm belongs into the family Psychidae, whose main characteristic is the bag the larvae build with silk and sticks of their hosts. Once built it is no longer abandoned. In the last stage the bag is fixed to a branch. There it remains till it turns into an adult. If it is a female, it will stay in the bag since females do not have wings and do not fly. The male, instead, gets out of the bag in search for females to be fertilized. Females lay some 1000 eggs which remain in the bag till they become larvae. They leave the bag to reach the vegetation and some time later they begin to build their own bag.
Pupa of Lazy
Actinote sp.
Perezosa Pupa/Lazy Pupa© Victoria Mansilla
Caterpillar of Oily Lazy
Actinote mamita
Perezosa aceitada O/Oily Lazy C© Cora Rimoldi
New moth: Velvetbean Moth
Anticarsia gemmatalis
Anticarsia gemmatalis© Cora Rimoldi
The larva of this species, the Velvetbean caterpillar, is considered a pest. It feeds on leaves and pods or seeds of legumes such as lucerne, pea, soybean, bean, clover, etc.
Butterflies and moths of April
Ghost Yellow
Eurema albula sinoe
Blanquita/Ghost Yellow© Sergio Cusano
Southern Fritillary
Euptoieta hortensia
Hortensia/Southern Fritillary© Sergio Cusano
White-patched Duskywing
Chionara autander autander
Emparchada/White-patched Duskywing© Sergio Cusano
Common Yellow
Eurema deva
Limoncito común/Common Yellow© Claudia y Tito Di Mauro
Russula Metalmark
Emesis russula
Acróbata rojiza/Russula Metalmark© Sergio Cusano
Big Lazy
Actinote pyrrha
Perezosa grande/Big Lazy© Sergio Cusano
American White Skipper
Heliopyrgus americanus bellatrix
Ajedrezada de lunar/American White Skipper© Sergio Cusano
Argentine Checkered Skipper
Pyrgus orcynoides
Ajedrezada menor/Argentine Checkered Skipper© Claudia y Tito Di Mauro
Cassius blue
Leptotes cassius
Yuyera/Cassius blue© Claudia y Tito Di Mauro
Arawacus ellida
Arawacus ellida
Élida/Arawacus ellida© Sergio Cusano

Atteva pustulella
Atteva pustulella© Claudia y Tito Di Mauro

Melanchroia aterea
Melanchroia aterea© Sergio Cusano
Whirlabout
Polites vibex catilina
Saltarina parda/WhirlaboutHembra © Sergio Cusano
Lyssipoides Metalmark
Riodina lyssipoides
Danzarina chica/Lyssipoides Metalmark© Sergio cusano
Ithra Crescent
Ortilia ithra
Bataraza/Ithra Crescent© Victoria Mansilla
Ithra Crescent
Ortilia ithra
Bataraza/Ithra Crescent© Sergio Cusano
Common Lazy
Actinote pellenea
Perezosa común/Common Lazy© Sergio Cusano
Common Lazy
Actinote pellenea
Perezosa común/Common Lazy© Sergio Cusano
Mexican Silverspot
Dione moneta
Moneta/Mexican Silverspot© Claudia y Tito Di Mauro
Mexican Silverspot
Dione moneta
Moneta/Mexican Silverspot© Sergio Cusano
Gulf Fritillary
Agraulis vanillae maculosa
Espejitos/Gulf Fritillary© Claudia y Tito Di Mauro
Poltys Satyr
Parypthimoides poltys
Ocelada doble líne/Poltys Satyr© Sergio Cusano
Fiery Skipper
Hylephila phyleus
Saltarina amarilla/Fiery Skipper© Claudia y Tito Di Mauro
Southamerican Lady
Vanessa brasiliensis
Dama pintada/Southamerican Lady© Sergio Cusano
Claudina Crescent
Tegosa claudina
Claudina/Claudina Crescent© J. Simón Tagtachian
Southern Buckeye
Junonia genoveva hilaris
Cuatro ojos común/Southern Buckeye© Sergio Cusano
Monarch
Danaus erippus
Monarca/Monarch© Claudia y Tito Di Mauro
Monarch
Danaus erippus
Monarca/Monarch© Sergio Cusano

Ash-colored Cuckoo
Coccycua cinerea
15-04-15 © Claudia y Diego Bastías



Yellow-chevroned Parakeet
Brotogeris chiriri
Yellow-chevroned Parakeet
14-04-15 © Claudia y Diego Bastías
Vermilion Flycatcher
Pyrocephalus rubinus
Vermilion Flycatcher
14-04-15 © Claudia y Diego Bastías

Going back to winter grounds

Cinnamon Teal
Anas cyanoptera
Cinnamon Teal
10-04-15 © J. Simón Tagtachian
Cinnamon Teal
11-04-15 © Pablo Serur
Cinnamon Teal
12-04-15 © Eduardo Carreyra
Cinnamon Teal
12-04-15 © Eduardo Carreyra
Cinnamon Teal
12-04-15 © Eduardo Carreyra
Straneck's Tyrannulet
Serpophaga griseicapilla
Straneck's Tyrannulet
12-04-15 © Eduardo Carreyra

We have begun to hear its song

Brown-hooded Gull
Chroicocephalus maculipennis
Brown-hooded Gull
10-04-15 © J. Simón Tagtachian
Snail Kite
Rostrhamus sociabilis
Snail Kite
10-04-15 © J. Simón Tagtachian
Snail Kite
10-04-15 © J. Simón Tagtachian
White-faced Whistling-Duck
Dendrocygna viduata
White-faced Whistling-Duck
15-12-14 © José Alberto Lell
White-tufted Grebe
Rollandia rolland
White-tufted Grebe
11-04-15 © Pablo Serur
Rosy-billed Pochard
Netta peposaca
Rosy-billed Pochard
15-12-14 © José Alberto Lell

The birds and the machine
Wattled Jacana
10-04-15 © J. Simón Tagtachian
Wattled jacana, great kiskadee and cattle tyrant are frequent clients of the machine. When it removes the floating vegetation many insects are exposed or fly away and all these birds make the most of this situation to get nice morsels.

Red-eyed Vireo
Vireo olivaceus
Red-eyed Vireo
10-04-15 © J. Simón Tagtachian
Plumbeous Rail
Pardirallus sanguinolentus
Plumbeous Rail
10-04-15 © J. Simón Tagtachian
Striated Heron
Butorides striata
Striated Heron
10-04-15 © J. Simón Tagtachian
Blue-and-yellow Tanager
Pipraeidea bonariensis
Blue-and-yellow Tanager
10-04-15 © J. Simón Tagtachian

With bugweed fruit


White-tufted Grebe
Rollandia rolland
11-04-15 © Silvia Loiacono

Limpkin
Aramus guarauna
24-03-15 © Claudia y Tito Di Mauro
04-04-15 © Claudia y Tito Di Mauro
The limpkin keeps growing and is learning how to eat. First and second part

[viedo id="285" options="name,description,photographer" size="large"]
Green Kingfisher
Chloroceryle americana
04-04-15 © Claudia y Tito Di Mauro

First the female preening herself and then the male perched with the typical flip of the tail

Domestic variant of Mallard Duck
Anas platyrhynchos domesticus
Ánade real dom/Dom Mallard Duck © Jorge La Grotteria
Ánade real dom/Dom Mallard Duck© J. Simón Tagtachian
Photographed during the Birding Challenge on 21st of February. In both pictures it is with a Rosy-billed Pochard. Difference in size is clearly appreciated.

The twists and turns of the Straneck's tyrannulet

Two among all the tyrannulets are very much alike - Serpophaga subcristata and Serpophaga munda. They dominated the scene when Berlioz described a third species resembling the previous ones: Serpophaga griseiceps in 1959. More than twenty years later new investigations determined that this tyrannulet Serpophaga griseiceps was the juvenile form of Serpophaga munda and again the number was reduced to the two initial tyrannulets.
In 1993 Straneck unifes Serpophaga subcristata and Serpophaga munda since they had the same vocalization. So the result was Serpophaga subcristata subcristata and Serpophaga subcristata munda as subspecies. But he describes a new species which does have a different song. The characteristics of this new tyrannulet coincided with the Berlioz's description of Serpophaga griseiceps. So Straneck recovers the name Serpophaga griseiceps. In 2004 the fusion of both Serpophaga griseiceps and Serpophaga munda was convalidated only on the grounds of the skins. In 2007 Straneck explains the flaws of this work and at the same time formally describes this tyrannulet as Serpophaga griseicapilla since it differs both in vocalization, size and crown. In Spanish it is called piojito trinador and in English is known as Straneck’s Tyrannulet, after Straneck. Something unusual since names are not given after living ornithologists.
Straneck's Tyrannulet
Serpophaga griseicapilla
10-04-15 © Claudia y Diego Bastías
Straneck's Tyrannulet
18-08-14 © Carlos González Ledo
The Straneck's tyrannulet is one of the winter visitors that has already arrived. Though it is not seen in the video, it can be perfectly heard. This tyrannulet is very much like the White-crested Tyrannulet Serpophaga subcristata which is a resident bird. A slight difference in size -the white-crested is one cm longer on average- and the crown of the Straneck's Tyrannulet has not or has less white than that of the White-crested Tyrannulet. These two characteristics are very difficult to distinguish at a distance.
But two clues help: the most reliable is vocalizations since they are quite different and secondly season -Straneck's tyrannulet is a winter visitor and the White-crested tyrannulet is all year round. So the worst situation is the bird in winter and in silence. 
White-crested Tyrannulet
Serpophaga subcristata
White-crested Tyrannulet
30-08-14 © Claudia y Tito Di Mauro
Let's hear the voice of this tyrannulet

Whistling Heron
Syrigma sibilatrix
Whistling Heron
09-04-15 © J. Simón Tagtachian
Cattle Tyrant
Machetornis rixosa
Cattle Tyrant
09-04-15 © Sergio Cusano
Ringed Teal
Callonetta leucophrys
Ringed Teal
09-04-15 © Nicolás Giorgio
Spectacled Tyrant
Hymenops perspicillatus
Spectacled Tyrant
04-04-15 © Claudia y Tito Di Mauro
Rosy-billed Pochard
Netta peposaca
Rosy-billed Pochard
07-04-15 © Nicolás Giorgio
Southern Lapwing
Vanellus chilensis
Southern Lapwing
07-04-15 © Nicolás Giorgio
Southern Lapwing
09-04-15 © Sergio Cusano
Limpkin
Aramus guarauna
Limpkin
06-04-15 © Claudia y Diego Bastías
Limpkin
07-04-15 © Nicolás Giorgio
Least Grebe
Tachybaptus dominicus
Least Grebe
08-04-15 © Alec Earnshaw

The least grebe caught a freshwater shrimp

Roseate Spoonbill
Platalea ajaja
Roseate Spoonbill
05-04-15 © Cora Rimoldi

The day before a group of 25 was seen flying by. At Coypu Pond I found these only three individuals 

04-04-15 © Claudia y Tito Di Mauro

Double-collared Seedeater
Sporophila caerulescens
08-04-15 © Cora Rimoldi

Snail Kite
Rostrhamus sociabilis
Snail Kite
04-04-15 © J. Simón Tagtachian
Cocoi Heron
Ardea cocoi
Cocoi Heron
04-04-15 © J. Simón Tagtachian
Cocoi Heron
04-04-15 © Claudia y Tito Di Mauro
Green Kingfisher
Chloroceryle americana
Green Kingfisher
04-04-15 © J. Simón Tagtachian

Solitary Black Cacique
04-04-15 © J. Simón Tagtachian

It introduces the bill and gapes with force to break the twig and reach the insect


Variable Oriole
Icterus pyrrhopterus
Variable Oriole
04-04-15 © J. Simón Tagtachian

With a succulent caterpillar taken from the galls of Sapium haematospermum.

Blue-and-white Swallow
Pygochelidon cyanoleuca
Blue-and-white Swallow
04-04-15 © J. Simón Tagtachian
Cinnamon Teal
Anas cyanoptera
Cinnamon Teal
04-04-15 © Silvia Loiacono
Cinnamon Teal
04-04-15 © J. Simón Tagtachian
Roseate Spoonbill
Platalea ajaja
Roseate Spoonbill
04-04-15 © Sergio Cusano
Roseate Spoonbill
04-04-15 © J. Simón Tagtachian
Roseate Spoonbill
04-04-15 © J. Simón Tagtachian

A group of 25 individuals


New butterfly species: Juno Silverspot
Dione juno juno
Juno/Juno Silverspot Juno/Juno Silverspot© Sergio Cusano

Swainson's Flycatcher
Myiarchus swainsoni
Swainson's Flycatcher
02-04-15 © Javier Ubiría
Streaked Flycatcher
Myiodynastes maculatus
Streaked Flycatcher
04-04-15 © Sergio Cusano
Tropical Kingbird
Tyrannus melancholicus
Tropical Kingbird
04-04-15 © Sergio Cusano
Brown-chested Martin
Progne tapera
Brown-chested Martin
02-04-15 © Sergio Cusano
White-winged Becard
Pachyramphus polychopterus
White-winged Becard
04-04-15 © J. Simón Tagtachian
Vermilion Flycatcher
Pyrocephalus rubinus
Vermilion Flycatcher
04-04-15 © Sergio Cusano
Vermilion Flycatcher
04-04-15 © Sergio Cusano

Spectacled Tyrant
Hymenops perspicillatus
Spectacled Tyrant
04-04-15 © Sergio Cusano
Least Grebe
Tachybaptus dominicus
Least Grebe
02-04-15 © Sergio Cusano
Red-crested Cardinal
Paroaria coronata
Red-crested Cardinal
02-04-15 © Sergio Cusano
Limpkin
Aramus guarauna
Limpkin
30-03-15 © Claudia y Diego Bastías
Greyish Baywing
Agelaioides badius
Greyish Baywing
30-03-15 © Claudia y Diego Bastías