Sunday, May 27, 2018

Sunday May 27, 2018 - by Chris Sloan

We left the dock under similar conditions to yesterday – light southwest winds, without much swell, and a relatively smooth ride out to the shelf under partly cloudy skies.  We reached the shelf break by around 7:45, and initially there was little activity.  It didn’t take long for that to change, though.  Over the course of the next hour, we gradually started picking up small number of Black-capped Petrels; even though the winds were only slightly stronger than yesterday, it was apparently enough to bring these graceful “flying field marks” back into the area.  By 9:00, we had already seen more than we saw all day yesterday!  
For the second day in a row, a jaeger paid us an early visit in the form of subadult Long-tailed Jaeger. Unlike yesterday’s “pet” Pomarine, this one moved through with purpose, powering in on the starboard side and never breaking stride as it continued on a straight line away from us.
Although it took a while for the numbers to build, we eventually attracted many more Wilson’s Storm-Petrels than yesterday, and Band-rumped Storm-Petrels were also fairly steady companions throughout the day.  Many made close passes up the slick, allowing numerous opportunities for us to study them.  

Notably, we saw at least two individuals who showed no signs of flight feather molt (one was the bird pictured above).  There are at least four Band-rumped Storm-Petrel populations in the Atlantic, of which all are potential candidates to be split as separate species.  One, Grant’s Storm-Petrel, breeds in the winter months; most Band-rumps seen off of North Carolina in spring are moulting their flight feathers, which is to be expected for birds just completing their breeding season.  However, a warm season breeding population, Madeiran Storm-Petrel, also appears to occur regularly here in small numbers.
In contrast to the two non-moulting individuals we observed, Madeirans appear, on average, to be smaller and blacker than Grant’s with a narrower bill.  On the other hand, in addition to the lack of flight feather moult, both individuals today showed a pronounced black line in the rump, similar to a Leach’s; this is a feature that has been ascribed to Madeiran by some authors.  Could these non-moulting birds have been Madeiran Storm-Petrels, or were they juvenile Grant’s?  Much remains unknown or uncertain about separating these populations.  This is why, in some respects, seabirding is the “last frontier” of birding!
Other than the storm-petrels, most of the day was spent steadily cruising through the warm water searching for pockets of activity.  We had small but steady numbers of Audubon’s and Cory’s Shearwaters, in addition to the occasional Black-caps.  Around noon, a small white tern in the slick caused a bit of confusion.  Initially, because it appeared shorter-tailed than would be expected of Arctic, it was identified as a Common Tern, but further study confirmed that it was, in fact, an Arctic Tern that appeared to be molting, or have lost, it’s longest tail feathers. Fortunately, it made a couple of close passes for all to enjoy.
The last exciting moment of the day came late in the afternoon, when a small black-and-white shearwater went zooming down the port side.  The markedly black upperwing and the wing cadence strongly suggested that it was a Manx, but unfortunately, it went away so quickly that no one was able to confirm it.  When it comes to birding in the Gulf Stream, there is always a reason to come back for more!  (Brian later confirmed that the last shearwater was indeed a Manx!)
Thanks to our great group of participants today, and thank you to our leaders: Chris Sloan, Seabird McKeon, Jeff Lemons, and Peter Flood.  A huge thank you to Chris for composing and providing photos for today's blog!

Species List May 27, 2018
Black-capped Petrel  59-60
Cory's Shearwater  15
Sooty Shearwater  2
Manx Shearwater  1
Audubon's Shearwater  28-38
Wilson's Storm-Petrel  70
Leach's Storm-Petrel  2
Band-rumped Storm-Petrel  10-11
Arctic Tern  1
Common/Arctic Tern  1
Long-tailed Jaeger  1
jaeger sp.  2

Black-capped Petrel - we had much better luck with them than yesterday!  There were some nice passes by the stern.
Though we had just a couple Sooties today, the second one flew into the slick and we were able to get some incredible views!
(*we should have some more photos from Peter tomorrow!)

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