People who are not familiar with seabird taxonomy and the most fascinating and enigmatic group of tubenoses...the
Pterodroma petrels, or gadfly petrels...usually have a challenge putting things together from older lists due to how names shift as knowledge improves. For example, Herald Petrel was what we shouted for years when we saw the different forms of what we now call Trindade Petrel - yet Herald Petrel is a species that is seen in the Pacific so if you saw one in the 1990s and looked it up online you would see they don't occur offshore from Hatteras. So people looking back at old lists wonder why we haven't seen Herald Petrels in years when we used to see them annually! When I started coming offshore here 27 years ago "Fea's" Petrel was still a mystery, though we saw them offshore from Hatteras, and ABA had not yet figured out how they would treat it. We now know we have three cryptic species just across the pond: Zino's, Desertas, and Fea's (Cape Verde) Petrel, and while previously it was presumed these were closely related to Soft-plumaged Petrel, we now know they are more closely related to the Bermuda Petrel or Cahow. Check out our note in Essential Info on our website: "What's in a Name?"
here
Species in the genus Pterodroma exhibit a strong sense of philopatry, meaning they tend to return to the island from which they fledge. This trait is what facilitates building populations and strengthening numbers by utilizing translocation projects. The most well known reintroduction program here in the US is one undertaken by Steve Kress who translocated Atlantic Puffin chicks from Canada to Eastern Egg Rock, Maine. Following this translocation and fledging of chicks he also used social attraction, playing calls, to build the colony. For us here in Hatteras the story of the Bermuda Petrel or Cahow is the one closest to home. These birds were thought to be extinct for over 300 years rediscovered only in 1951 on an expedition led by Robert Cushman Murphy. They are what we call a Lazarus Species, one that has risen from the dead. The island of Nonsuch in Castle Harbor, Bermuda is a perfect location for a colony and two colonies have been established here over the past 26 years by using translocation and social attraction. A huge success for this species that had only a handful in existence when rediscovered in 1951. The Cahow has now easily surpassed the Zino's Petrel, another Lazarus Species rediscovered in 1969 on Madeira, in number leaving Zino's as one of the most critically endangered gadfly petrels on the planet with little conservationists can do to bolster the population of an estimated 160 individuals. These birds amazingly are still predated by cats in the mountains where they breed on Madeira with local groups insisting the cats be trapped and moved, not euthanized. Natural disasters like fire also have caused trouble for them over the years. It is incredible to think that the Zino's Petrel is not the most critically endangered Pterodroma, but that the Magenta Petrel or Taiko is thought to have only about 12 breeding pairs and maybe 120 individuals in existence. Again, translocation and protected areas are helping to hopefully build numbers of this species as well, yet another Lazarus Species only rediscovered in 1978! All of these pieces help to explain why the species nesting on Madeira differ from those on Bugio differ from those nesting on the Cape Verde Islands. They are very loyal to the island(s) from which they fledge.
Only recently have the criteria to separate the slimmer, more petite Zino' Petrel from the other two species been ironed out finally allowing the photographic record from 16 September 1995 offshore from North Carolina to be accepted as the first for North America! The other two "Fea's type" gadfly petrels overlap in some features making the identification at sea challenging though hopefully some more clues to separate them at sea away from their breeding islands are on the way as seabird experts like Robert Flood and Hadoram Shirihai work to sort it out! There are a few things we can look for to help sort out these cryptic species like the amount of white in the underwing coverts, the amount of barring on the flanks and in the "armpit," and the size, shape and bill of the individual observed.
Work done on the two populations of "Fea's type" Petrels in breeding colonies indicates that the birds on Bugio (the Desertas) and Fogo (Cape Verde) are distinct enough to warrant species status. Scientific names are Pterodroma deserta and Pterodroma feae. This taxonomy has been in flux with these birds initially thought to be a subspecies of Soft-plumaged Petrel then sorted into their own with status as Fea's Petrel with three subspecies. Zino's Petrel was pulled out of the fray and placed into its own species. As long ago as 1955 the birds nesting on Bugio were thought to be distinct and the scientific name for these Desertas nesting petrels was suggested as Pterodroma deserta. This is why some people have been a bit confused...previously we just had the Fea's Petrel Pterodroma feae, which had already been split into species by some taxonomists but we had only subspecific status here in the Americas (AOS). On our trips birds we see can be assigned to the larger Desertas Petrels so in recent years we would designate them as Pterodroma feae deserta while the Fea's (Cape Verde) Petrel was listed as Pterodroma feae feae. Many of the individuals we have photographed on our trips from Hatteras show the diagnostic large head and bill of Desertas Petrel and underwing coloration that is between Zino's and Fea's (Cape Verde) Petrels. Occasionally we have individuals that might not be as straightforward to identify (the Fea's / Cape Verde Petrel falls in between Zino's and Desertas in size) but molt timing and other characteristics strongly favor them being Desertas Petrels. Any individuals we're unsure about, like our Desertas Petrel sighting in late August of this year, will be listed as "Fea's type" until we have reviewed the images and received additional opinions from seabird experts.
While both Brian and I have experience with Desertas and Zino's Petrels from offshore trips in Madeira, neither of us has yet had the opportunity to get to the Cape Verde Islands for a good examination of those gadflies. Tracking studies show that while adult Zino's and Desertas range far from their breeding locations Fea's (Cape Verde) Petrels tend to stay closer to home. When you think a bit about what species we see offshore from Hatteras and where they nest, it makes sense that birds nesting near the Desertas Petrel like Atlantic Cory's and Band-rumped Storm-Petrels are regular visitors while Cape Verde Shearwater is incredibly rare and Cape Verde Storm-Petrel has not yet been recorded offshore here. It is quite likely the larger weather patterns and systems make it easier for some species to get here and others to range elsewhere. Food availability has so much to do with it as well, and we all know seabirds roam! So it is not out of the question that a definitive Fea's (Cape Verde) Petrel will be spotted offshore here or show up in some older photographic records. We're revisiting a few of those now.
Anyhow, the US has finally again caught up with the rest of the world and eBird decided to designate the records offshore from Hatteras as Desertas Petrels. And while this is most likely what they are, the at sea separation of Desertas and Fea's (Cape Verde) Petrel continues to be a challenge though hopefully with all of the tools we have now we will at least have some idea when a nice, definitive Fea's (Cape Verde) Petrel shows up offshore here! At this time there have not been any known records of this species offshore from the US.
With 2025 in its last couple of months we're already thinking about what we might find offshore next year! Our schedule is up on the website and the reason we're dubbed Pterodroma Alley is because this is the one place in the US you can head offshore and expect to see at least one species of gadfly petrel (Black-capped) on a day trip...but the possibility of Bermuda, Desertas, and Trindade Petrel are unparalleled elsewhere off of the Eastern Seaboard. We have quite a schedule for 2026,
click here, with a few sets of 2/3 day trips in the spring and summer to maximize the list of species for participants and the legendary Spring Blitz running daily from 20 May through 6 June! You never know what you'll find until you go looking, we'll see you out there! - Brian & Kate
Some references for those of you that are interested in reading more:
Brusco et al. 2021. Gadfly petrels of the Pterodroma feae-complex in southwestern Atlantic Ocean, Brazil. Ornithology Research. 29:160-165.
Flood, Robert. 2015. Process for at sea identification of the fea-complex applied to a petrel observed off the Isles of Scilly. Seabird 28: 78-88.
González-SolÃs et al. 2024. Life history, population dynamics and impacts of cat predation on an endemic gadfly petrel in Cabo Verde. Endang Species Res. 55: 187-203.
Jesus et al. 2009. Phylogenetic relationships of gadfly petrels Pterodroma sp from the Northeastern Atlantic Ocean: molecular evidence for specific status of Bugio and Cape Verde petrels and implications for conservation. Cambridge University Press. Bird Conservation International 19 (3): 199-214.
RamÃrez et al. 2013. Year-round distribution and habitat preference of the Bugio Petrel. Mar Ecol Prog Ser. 476: 269-284.
RamÃrez et al. 2015. Conservation implications of consistent foraging and trophic ecology in a rare petrel species. Animal Conservation. 19: 139-152.
Ramos et al. 2016. Global Spatial Ecology of Three Closely Related Gadfly Petrels. Scientific Reports. Nature.
This figure is © Robert Flood and taken from the paper listed above which you can find online
here This shows the underwing patterns for the birds in this complex and you can see the overlap but also the general trends for each species. We also highly recommend his Multimedia Identification Guide to North Atlantic Seabirds - specifically
Pterodroma petrels if you don't already have it!
Desertas Petrel offshore of Bugio Island 28 June 2023. This individual has a pretty clean "armpit" and a bit of white in the underwing coverts, that blocky head and thick bill are evident.
Desertas Petrel offshore of Bugio Island 30 June 2023. An individual with some barring in the "armpit" but not incredibly strong as has been noted in Fea's (Cape Verde) Petrels. And a bit darker in the underwing. Still has that nice blocky head and thick bill.
Zino's Petrel offshore from Madeira 30 June 2023. You can see how much lighter the underwing coverts are on the edges in this individual. The small head and petite bill plus the more slender body and tapered tail all support the identification. In life these birds reminded me very much of Bermuda Petrel.
If you're interested in getting more familiar with this group of gadflies we recommend heading to Madeira to go offshore with
Madeira Wind Birds these trips target Zino's Petrel but are well rounded and you can really maximize your chances to see Desertas Petrel here too.
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