While no description was published at the time, a drawing of the specimen produced by Sydney Parkinson can be recognised as the form breeding on the Cape Verde Islands.

[7] The forms breeding in Macaronesia on Madeira, Bugio in the Desertas Islands, and in the Cape Verde archipelago were long considered to be subspecies of the southern hemisphere soft-plumaged petrel P. mollis, but differences in size, vocalisations, breeding behaviour and mitochondrial DNA analysis showed that the northern birds are not closely related to P. mollis,[8] and that the Bermuda petrel or cahow may be the closest relative of the Macaronesian birds.

[9] More recently, some authorities have further split Fea's petrel, separating the Desertas Islands breeding birds from those in the Cape Verde archipelago.

[10] Sangster estimated that the two Macaronesian species diverged at the end of the Early Pleistocene, 850,000 years ago,[8] although the methodology used to establish this time scale has subsequently been questioned.

This suggests that despite the close physical proximity of the two species of gadfly petrel found in the Madeiran archipelago, they may have arisen from separate colonisations of mainland Madeira and, later, the Desertas Islands.

A summary of data from a morphological study sheds light on the issue:[13] In terms of ratios: It breeds on four islands of Cape Verde in the eastern Atlantic Ocean: Fogo, Santo Antão, São Nicolau and Santiago.