Little boy (child) with ( spiked? ,straight hair ) it means that his hair is "parado,sucio", may be a little dirty
Ojitos: little eyes
de yacaré: yacaré is our south american alligator, although smaller
barriguita :tummy chifladora: his tummy makes noises because he is hungry
chiflar: to whistle chiflador: a person who whistles
lomito: is this case,the back of the little boy (la espalda)
the boy´s back is brown like coffee(café:coffee), he is a "mestizo"
This song is about our river Uruguay,and poor people that live in the riverbanks ,its name is "Río de los pájaros",bird's river
Enjoy the music, keep on learning!