You could be forgiven for thinking that I only ever post about birds from Costanera Sur in Buenos Aires. The Guira Cuckoo will make an even dozen galleries from the reserve, but I surprise myself that it has taken this long.
They are common and confiding birds that form small flocks and roost together in a cuckoo knot. The birds that frequent the promenade at Costanera Sur are especially bold and will even try to stare a birdwatcher down rather than give way at the parilla (pop-up café).
They undulate back and forth between the reed beds and the light woodland on the reserve and the wall that lines the promenade. The promenade has been marooned half a kilometre inland after land reclamation created the wetland on the banks of the Rio Plata. The wall provides a convenient place to tick-bathe. The birds raise the feathers on their backs to allow the UV rays to penetrate to the skin. This deters parasites and must just feel good.
Though they disperse a little during the day, the cuckoos form up again during the late afternoon as the sun comes inland and lights the Laguna de los Copios to the east of the promenade.
This is when the Guira Cuckoo looks its best. It can look scruffy and drab in poor conditions, but the evening sun shows up the subtle colour variations and catches details that are otherwise easily missed.