Hi Joshua et al.,
This bird is a first year cauta or steadi. A first year Salvin’s would have way more sharply demarcated primary tips, smudgy lesser underwing coverts and a more solid grey head. The ‘messy’ lesser under primary coverts are normal for cauta or steadi.
Steve’s article may be useful: http://www.neotropicalbirdclub.org/neobird/NeoBird4-Howell.pdf
Cheers,
Nikolas
