Yesterday, 18th September, I went to the Costanera Sur reserve during the morning and was able to observe the following 83 species.
White-tufted Grebe
Pied-billed Grebe
Great Grebe
Neotropic Cormorant
Cocoi Heron
Great Egret
Snowy Egret
White-faced Whistling-Duck
Coscoroba Swan
Black-necked Swan
Speckled Teal
Red Shoveler
Cinnamon Teal
Silver Teal
Rosy-billed Pochard
Black-headed Duck
Argentine Ruddy-Duck
Roadside Hawk
Southern Crested-Caracara
Chimango Caracara
Plumbeous Rail
Red-gartered Coot
White-winged Coot
Red-fronted Coot
Common Gallinule
Spot-flanked Gallinule
Wattled Jacana
White-backed Stilt
Southern Lapwing
Lesser Yellowlegs
Grey-hooded Gull
Brown-hooded Gull
Snowy-crowned Tern
Picazuro Pigeon
Rock Pigeon
Eared Dove
White-tipped Dove
White-eyed Parakeet
Nanday Parakeet
Monk Parakeet
Guira Cuckoo
Glittering-bellied Emerald
Golden-breasted Flicker
Narrow-billed Woodcreeper
Bar-winged Cinclodes
Rufous Hornero
Sulphur-throated Spinetail
Wren-like Rushbird
Freckle-breasted Thornbird
Blue-billed Black Tyrant
Many-coloured Rush Tyrant
Great Kiskadee
Grey-crowned Tyrannulet
Vermilion Flycatcher
Grey-breasted Martin
White-rumped Swallow
Plush-crested Jay
House Wren
Chalk-browed Mockingbird
Creamy-bellied Thrush
Rufous-bellied Thrush
Masked Gnatcatcher
Masked Yellowthroat
White-lined Tanager
Golden-billed Saltator
Red-crested Cardinal
Yellow-billed Cardinal
Rusty-collared Seedeater
Saffron Finch
Rufous-collared Sparrow
Black & Rufous Warbling Finch
Ringed Warbling Finch
Black-capped Warbling Finch
Hooded Siskin
Epaulet Oriole
Screaming Cowbird
Shiny Cowbird
Bay-winged Cowbird
Yellow-winged Blackbird
Orange-backed Troupial
Bonaparte's Blackbird
House Sparrow
Common Starling
White-tufted Grebe
Pied-billed Grebe
Great Grebe
Neotropic Cormorant
Cocoi Heron
Great Egret
Snowy Egret
White-faced Whistling-Duck
Coscoroba Swan
Black-necked Swan
Speckled Teal
Red Shoveler
Cinnamon Teal
Silver Teal
Rosy-billed Pochard
Black-headed Duck
Argentine Ruddy-Duck
Roadside Hawk
Southern Crested-Caracara
Chimango Caracara
Plumbeous Rail
Red-gartered Coot
White-winged Coot
Red-fronted Coot
Common Gallinule
Spot-flanked Gallinule
Wattled Jacana
White-backed Stilt
Southern Lapwing
Lesser Yellowlegs
Grey-hooded Gull
Brown-hooded Gull
Snowy-crowned Tern
Picazuro Pigeon
Rock Pigeon
Eared Dove
White-tipped Dove
White-eyed Parakeet
Nanday Parakeet
Monk Parakeet
Guira Cuckoo
Glittering-bellied Emerald
Golden-breasted Flicker
Narrow-billed Woodcreeper
Bar-winged Cinclodes
Rufous Hornero
Sulphur-throated Spinetail
Wren-like Rushbird
Freckle-breasted Thornbird
Blue-billed Black Tyrant
Many-coloured Rush Tyrant
Great Kiskadee
Grey-crowned Tyrannulet
Vermilion Flycatcher
Grey-breasted Martin
White-rumped Swallow
Plush-crested Jay
House Wren
Chalk-browed Mockingbird
Creamy-bellied Thrush
Rufous-bellied Thrush
Masked Gnatcatcher
Masked Yellowthroat
White-lined Tanager
Golden-billed Saltator
Red-crested Cardinal
Yellow-billed Cardinal
Rusty-collared Seedeater
Saffron Finch
Rufous-collared Sparrow
Black & Rufous Warbling Finch
Ringed Warbling Finch
Black-capped Warbling Finch
Hooded Siskin
Epaulet Oriole
Screaming Cowbird
Shiny Cowbird
Bay-winged Cowbird
Yellow-winged Blackbird
Orange-backed Troupial
Bonaparte's Blackbird
House Sparrow
Common Starling