Machetornis rixosa
These birds are ubiquitous throughout north and central Argentina and we have our share in the Ibera Marshes. They are part of the Tyrannidae family along with other Flycatchers and Tyrants.
This bird has brown upperparts and yellow underparts. The head is grey with a white throat and the bill is black and quite long. There is a concealed red crest which is not usually seen unless the bird has been out in heavy rain. See photo below of wet bird
