Española, Galapagos, Ecuador.
Nazca Booby was split from Masked Booby (S. dactylatra) based on its orange (not yellow) bill and white (not black) central tail feathers. Both of these features are visible in this photo. On a few islands they nest together without interbreeding. Reference: Pitman, R. L.; Jehl, J. R. (1998): Geographic variation and reassessment of species limits in the "Masked" Boobies of the eastern Pacific Ocean. Wilson Bulletin 110(2): 155-170.