24 Apr 2018

24 Apr 18 - Atlantic Odyssey - Day Twenty Six: Ascension Island Band-rumped Storm-petrels

There was one final Seabird I wanted to see around Ascension Island: the Ascension Island population of Band-rumped Storm-petrels. I had seen a few Band-rumped Storm-petrels on the day before we reached Ascension Island. However, as we were around 150 nautical miles from the island, there is no certainty they were from the Ascension Island population. A few Birders had seen some around Boatswainbird Island on the first visit, but they they were brief sightings & none were seen from the bridge wing where I was standing. Therefore, as we were weighing anchor to leave Ascension Island, I headed back to the bridge wing with a fresh mug of coffee & with no intention of leaving my vantage position until I seen some Band-rumped Storm-petrels or it got dark. There were none around Boatswainbird Island, but fortunately, I picked up the first of at least eight as we were finally sailing away from Ascension Island.
Band-rumped Storm-petrel: Like the St Helena population, they show a slightly forked tail, a prominent clean-cut white rump & prominent pale wingbar
Band-rumped Storm-petrel: The white rump extends well down the sides of the rump
Band-rumped Storm-petrel: Another view of the same individual
Band-rumped Storm-petrel: Another view of the same individual
Band-rumped Storm-petrel: A better view of the sides of the rump
Band-rumped Storm-petrel: An underwing shot of the same individual
Band-rumped Storm-petrel: A final underwing shot of the same individual
Band-rumped Storm-petrel taxonomy is complex. A few years ago, Band-rumped Storm-petrels were understood to breed on islands in the Tropical Atlantic & Pacific Oceans, including the Portuguese Berlengas Islands, Madeira, Canaries, Azores, Cape Verde, Ascension Island, St Helena, as well as, the Galapagos, Hawaii & islands belonging to Japan. In the last decade, studies into the breeding times of year, DNA, vocalisation & morphology have identified that there are probably three additional species which breed on the Tropical North Atlantic islands. Studies of the Band-rumped Storm-petrels which breed on Ascension Island & St Helena are only just starting, but there must be a reasonable chance of additional splits of these populations once these studies have been completed. We had had good views of many Band-rumped Storm-petrels on St Helena & now we had seen & photographed individuals from the Ascension Island population.
Band-rumped Storm-petrel: The second individual didn't come very close
Band-rumped Storm-petrel: Another photo of the second individual showing the extensive white sides to the rump
The third Band-rumped Storm-petrel was a heavily worn individual.
Band-rumped Storm-petrel: Note, the worn plumage & active wing moult
Band-rumped Storm-petrel: This was a much tattier & worn individual
Band-rumped Storm-petrel
Band-rumped Storm-petrel: Note, the wing moult
Band-rumped Storm-petrel: It didn't show the crisp clean markings of the first two individuals
Band-rumped Storm-petrel
Band-rumped Storm-petrel
Band-rumped Storm-petrel: A final show of the third individual disappearing
There were also a few Leach's Storm-petrels. They were longer-winged & had a variable dark band through the centre of the white rump.
Leach's Storm-petrel: This individual has a very distinctive black band through the centre of the rump
Leach's Storm-petrel: The tail is deeper forked than the Band-tailed Storm-petrels
Leach's Storm-petrel: The feet also project beyond the tail in this one photo
Leach's Storm-petrel: Another photo of the same individual
Leach's Storm-petrel: The upper wing bar is also very obvious
Leach's Storm-petrel: The white sides to the rump are not as obvious as on the Band-tailed Storm-petrels
Leach's Storm-petrel: A final view of this first individual showing that the wings are longer, the white on the sides of the rump are less extensive & the tail is deeper forked than the Band-rumped Storm-petrels
Finally, some photos of a second Leach's Storm-petrel.
Leach's Storm-petrel: Superficially this looks like a Band-rumped Storm-petrel
Leach's Storm-petrel: However, it looks longer-winged & shows a dark bar across this centre of the white rump
Leach's Storm-petrel: Unusually, this individual doesn't appear to have a forked tail
Leach's Storm-petrel: The white is less extensive on the sides of the rump

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