Wednesday, August 11, 2021

August 6 & 7, 2021 - Kate Sutherland

After dealing with weather issues last weekend, we were glad to see that it looked like we would have a nice window to get offshore for our trips on the 6th and 7th.  Winds were light from the east/southeast on Friday and Saturday they were more southerly, with some thunderstorms in the forecast, but we were hopeful we could get out there and work around them, maybe even have some birds riding the edges of the squalls.  Friday we encountered all of our usual, Gulf Stream species, and while birds came in to investigate the chum they didn't really come all that close.  Saturday was the opposite and even our rarities - Brown Booby and Trindade Petrel - came in super close for excellent views!  Those participants who were able to join us for both departures saw 12 pelagic species plus some cooperative offshore Bottlenose Dolphins.  
Gadfly petrels were represented by almost 100 Black-capped Petrels over two days and one fearless, dark morph Trindade Petrel (Ed Corey). 
While the Black-cappeds kept some distance on Friday, Saturday they came in well to the chum and even dropped down to feed in the slick behind us.  We photographed at least two or three birds that recently fledged - always nice to get to see those sharp looking immature Black-cappeds! (Kate Sutherland) 

The Trindade Petrel popped into the slick right behind us a little before 1130 on Saturday, flew off, then circled back putting us in good light and coming in high to investigate.  It was a spectacular view for all aboard!
Shearwaters were cooperative as well with a nice, feeding flock of Cory's, Scopoli's, and Greats on Saturday morning.  It was a bit easier to get nice views of the two different Calonectris shearwaters when they were flying around us closely feeding, since they can sometimes be hit or miss in the slick.  We had a number of Atlantic Cory's in that group, but even more Scopoli's, plus a few individuals photographed that were truly in between.  As many of you know if you have been offshore with us, I am pretty conservative when it comes to slapping an identification on something we are still figuring out and a number of the Cory's / Scopoli's can still have us scratching our heads even when seen well!  Overlap in size and variation for each species can make it difficult to pin down every bird, and those that pass by in the distance, unless seen well and photographed, make it on the list as "Cory's types."  Currently the only feature that is considered diagnostic for separating these two species is the amount of white visible in the underside of the outermost primary, p10.  We differentiate them as Scopoli's having a white tongue of 30% or more and Cory's having little to no white.  Some fall in between and if there are other supporting features, like a slender / thick bill or small / large head, we could identify them as one or the other.  Regardless of how challenging these can be to identify, what is really exciting is that we see a lot of Scopoli's Shearwaters here offshore from Hatteras in the summer!  (Ed Corey) 
Great Shearwaters were cooperative both days coming in well to the boat, but Audubon's were a bit easier to find on Friday's trip and we are seeing both fresh, young birds that have recently fledged in addition to browner, more worn adults.
Wilson's Storm-Petrels were around in good numbers both days and came in well to the fish oil and chum.  It was an incredible opportunity to photograph them close to the boat and it's always exciting to see the yellow webs between the toes and to see them diving for small pieces of fish! (Kate Sutherland) 
We just had one Leach's over the two day set on Saturday, and it didn't show very well.  Band-rumped Storm-Petrels, however,  were super cooperative especially on Saturday!  Most of the individuals that were photographed looked to be growing p10 putting them into the group of winter breeding Band-rumpeds, presumably.
Saturday morning, after working the feeding flock of shearwaters, we decided to toss out a homemade chum block and see what we could entice to visit.  Black-cappeds, shearwaters, and storm-petrels, both Wilson's and Band-rumpeds, were all very cooperative!  A little after 1000 an adult Brown Booby decided to check us out, it must have seen the slick from a distance because it appeared right over the bow, looking down into the water, and flew off.  Obviously we didn't have anything alive to convince it to hang out for a bit and it moved on.  Not before everyone aboard had an awesome view of this sleek sulid! (Kate Sutherland) 
Tropical terns are still a week or two out I guess because if there were any around we might have found some over the shearwater flock on Saturday.  We did see one Bridled Tern in the distance on Saturday afternoon, so hopefully they will begin to show this weekend!  Summer is on the way!
Thanks to everyone who joined us out there and a big thank you to our leaders, Ed Corey, Jeff Lemons, and Andrew Rapp, for making sure that everyone saw the birds and had a great time!  Thanks to Ed for sharing some of his photos for the blog post.  While most of our summer departures are full, we do have space on our fall trips - you just never know what you might find out there! - Kate

Species List for August 6 / 7
Trindade Petrel - 0 / 1
Black-capped Petrel - 28 to 33 / 60
Cory's Shearwater - 6 / 13
Scopoli's Shearwater - 18 / 16
Cory's / Scopoli's Shearwater - 35 / 104
Great Shearwater - 18 / 36
Audubon's Shearwater - 23 / 6
Wilson's Storm-Petrel - 150 to 170 / 130 to 145
Leach's Storm-Petrel - 0 / 1
Band-rumped Storm-Petrel - 4 to 6 / 11 to 15
Leach's / Band-rumped - 0 / 1
Brown Booby - 0 / 1 adult
Red-necked Phalarope - 3 / 0
Bridled Tern - 0 / 1
Common Tern - 1 / 0
Tern species - 3 / 0
Bottlenose Dolphin (offshore) - 15 to 18 / 0
Wandering Glider - 1 / 0

Another image of the Trindade Petrel (Kate Sutherland)
And a dorsal view of the Brown Booby (Ed Corey)
Black-capped Petrels made some nice passes!  Here is the dorsal of one of the fresh individuals (Ed Corey)
Black-capped Petrel ventral with pretty dark margins in the underwing coverts (Kate Sutherland)
Black-capped Petrel dorsal, this individual has a fairly pale face and nape (Kate Sutherland)
Atlantic Cory's Shearwater showing little white in the under primaries, specifically p10.  (Ed Corey)
Scopoli's Shearwater showing that diagnostic white in p10 (Kate Sutherland)
And one showing the more delicate bill (Ed Corey)
Here is one of those birds that is likely a Cory's Shearwater, but had a bit of white in p10 (Kate Sutherland)
And one that I left as a Cory's type that had some white in p10 but not 30% - this one is likely a Scopoli's (Kate Sutherland)
Great Shearwaters have a black bill, blackish cap, and a dark belly patch with mottled looking underwings when compared to Cory's type shearwaters above (Kate Sutherland)
Audubon's Shearwater - these small shearwaters are black above and white below (Ed Corey)
A few more images of Wilson's Storm-Petrels.
Their long legs usually are visible beyond the tail (both by Kate Sutherland)
They were feeding close to the boat on Saturday!
Band-rumped Storm-Petrels have much shorter legs than Wilson's (Ed Corey)
And their wings are much longer than those of Wilson's, compare to photos above! (Kate Sutherland)
Red-necked Phalaropes were fairly cooperative on Friday!  Here you can see the streaked back and fine bill characteristic of this species (Kate Sutherland)
And finally, a nice image of the Common Tern that visited us offshore of the shelf break on Friday! (Kate Sutherland)

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