Zino's Petrel (Pterodroma madeira), or Freira, is a small seabird in the gadfly petrel genus. It has also been called the "Madeira Petrel", but this name invites confusion with the Madeira Storm Petrel and is best avoided. Zino's Petrel was previously considered to be a subspecies of Soft-plumaged Petrel P. mollis, but they are not closely related. However, P. madeira is very closely related to Fea's Petrel, another species recently split from P. mollis. They are estimated to have diverged at the end of the Early Pleistocene, 850,000 years ago.(Sangster et al., 2002) Given the uncertainties of molecular dating in Procellariiformes (Rheindt & Austin, 2005), this must be considered very tentative however.
It breeds in the north Atlantic in the mountains of the main island of Madeira. This endangered species nests in colonies in burrows. Fewer than 80 breeding pairs (2005 census) are left, estimate total of 400 birds.
This seabird is strictly nocturnal at the breeding sites to avoid predation by gulls. Like most petrels, its walking ability is limited to a short shuffle to the burrow.
This long-winged petrel has a grey back and wings, with a dark "W" marking across the wings. The undersides of the wings are dark and the belly is white. It has a fast impetuous flight. It picks planktonic food items from the ocean surface.
This species is 32"?34 cm in length with an 80"?86 cm wingspan and weighs 200-230 grams. It is very similar to the Fea's Petrel, but is smaller and has a thinner black bill.
It is named after the Paul Alexander Zino, who was instrumental in its conservation during the latter half of the twentieth century.
The identification of Zino's Petrel, and its separation from Fea's Petrel under field conditions is an unresolved problem. The US ornithologist Michael Tove has worked on this problem, and believes that wing-shape is a reliable feature for the separation of this species-pair. This has been disupted by other authors, such as Andrew Harrop. However, Tove has criticised the approach of his critics, arguing that he has presented detailed data to support his conclusions, whereas those who are unwilling to accept them are adopting the tactic of "Truth by Decry".