September, 1990 is by Argentine artist Marta Minujin. Located by the 18th St. N.W. entrance of the Art Museum of the Americas by the Organization of American States building, the wiry person is 1 of 12 months created by Minujin.
Working through a Yahoo translator and the nice people from the museum, I learned September 1990 has holes between metal bars so birds can nest in it. The three-dimensional piece changes with the landscape.