HI again.
In March 2018, during a new tour of AviFauna, we visited twice the area of Curral Velho (last breeding site, in the islet) for several hours and we couldn't see any bird. We were informed that in the last years Frigatebirds have practically dissapeared from the area and probably from the entire island. For more information about the history and fate of the Frigatebirds in the Cape Verdes, see these references:
LÓPEZ SUÁREZ, P., C.J. HAZEVOET & L. PALMA (2012): Has the magnificent frigatebird Fregata magnificens in the Cape Verde Islands reached the end of the road? Zoologia Caboverdiana 3 (2): 82-86.
LÓPEZ SUÁREZ, P., N. VARO CRUZ, C.J. HAZEVOET & L.F. LÓPEZ JURADO (2005): Restricted nesting habitat and reproductive failure of Magnificent Frigatebirds Fregata magnificens in the Cape Verde Islands. Atlantic Seabirds 7 (3): 107-120 + photo in p. 106.