THis is the only quail species on the Azores.

Common Quail
Coturnix coturnix conturbans
south of Raminho,
Terceira Island,
Azores,
Portugal
15 July 2013

This species is common and widespread all across the island of Terceira. This is apparently a subspecies found on these islands and an Internet search for Coturnix coturnix conturbans will show many similar images. The birds on the Azores (subspecies conturbans) have the dark face as shown in these images.

First image shows the quail calling from a rock in a field. When approached, this species hunkers down and hides rather than flying away and the 2nd image shows one of the shots I took when I got fairly close.