A bit of schistisagus? - Comments
Reply to post on ID Frontiers 14:45 19.11.2013
Hi Frode. An interesting gull indeed. One feature that I always focus on when considering a putative Slaty-backed Gull in any age class is the relative position of P7 and P8 on the folded wing with respect to the end of the tail. Understand of course that this provides for fully grown rectrices and primaries. As shown on your first cycle bird, P8 clearly surpasses the tail tip while P7 does not or at least does not appear to. P7 does in fact, look to end short of the tail tip in two photographs. In other similar large gull species that I am familiar with in first cycle, I consistently find that P7 will at least reach the tip of the tail and often will extend slightly beyond. I might suggest that you key in on this character in further photographic research. I should also note that I see nothing in the plumage or structure that is inconsistent for Slaty-backed, but will leave that for others to comment on. An issue that I find beyond my scope is the potential of some type of hybrid combination, although I have tried to consider that entity. Kevin McLaughlin. Hamilton, Ontario, Canada.
Hi Frode. An interesting gull indeed. One feature that I always focus on when considering a putative Slaty-backed Gull in any age class is the relative position of P7 and P8 on the folded wing with respect to the end of the tail. Understand of course that this provides for fully grown rectrices and primaries. As shown on your first cycle bird, P8 clearly surpasses the tail tip while P7 does not or at least does not appear to. P7 does in fact, look to end short of the tail tip in two photographs. In other similar large gull species that I am familiar with in first cycle, I consistently find that P7 will at least reach the tip of the tail and often will extend slightly beyond. I might suggest that you key in on this character in further photographic research. I should also note that I see nothing in the plumage or structure that is inconsistent for Slaty-backed, but will leave that for others to comment on. An issue that I find beyond my scope is the potential of some type of hybrid combination, although I have tried to consider that entity. Kevin McLaughlin. Hamilton, Ontario, Canada.
Reply to post on ID Frontiers 15:13 19.11.2013
Hi Frode. That's a very interesting bird. The only thing that struck me compared to SBGs I've in seen in Japan was the outermost tail feather which seems more distinctly barred than many SBG have in this age class. Though I'm not sure that would rule one out were you say to see this bird in Japan or somewhere else in the core range. Regards, Clive Harris.
Hi Frode. That's a very interesting bird. The only thing that struck me compared to SBGs I've in seen in Japan was the outermost tail feather which seems more distinctly barred than many SBG have in this age class. Though I'm not sure that would rule one out were you say to see this bird in Japan or somewhere else in the core range. Regards, Clive Harris.
New post on ID Frontiers 00:10 20.11.2013
I have engaged in some interesting discussion with Frode and Julian Hough today about the Norwegian gull. Julian forwarded me a link to the photos and discussion regarding the Connecticut gull from earlier this year that had apparent Slaty-backed characters. This included some thought provoking points from Peter Adriaens both pro and con SBG. In looking at Frode's photos of the Norwegian gull, I am compelled to wonder about the pattern showing on R4, R5 and R6 and how this can fit SBG in first cycle. R4 has some basal white "stippling" and R5 more of a marbled effect. R6 has a "dowitcher" like pattern on both webs to the tip. My understanding of typical juvenal SBG rectrix pattern is that white on the shaft, broadest towards the base, is all that that will normally "sully" otherwise dark feathers throughout. The rectrix pattern on Frode's gull runs contra Peter's detail regarding tail pattern in discussing the Connecticut gull as well. It seems prudent to research rectrix patterns in first cycle with an eye to finding consistencies along with variation in first cycle Slaty-backed Gull. Kevin McLaughlin. Hamilton, Ontario, Canada.
I have engaged in some interesting discussion with Frode and Julian Hough today about the Norwegian gull. Julian forwarded me a link to the photos and discussion regarding the Connecticut gull from earlier this year that had apparent Slaty-backed characters. This included some thought provoking points from Peter Adriaens both pro and con SBG. In looking at Frode's photos of the Norwegian gull, I am compelled to wonder about the pattern showing on R4, R5 and R6 and how this can fit SBG in first cycle. R4 has some basal white "stippling" and R5 more of a marbled effect. R6 has a "dowitcher" like pattern on both webs to the tip. My understanding of typical juvenal SBG rectrix pattern is that white on the shaft, broadest towards the base, is all that that will normally "sully" otherwise dark feathers throughout. The rectrix pattern on Frode's gull runs contra Peter's detail regarding tail pattern in discussing the Connecticut gull as well. It seems prudent to research rectrix patterns in first cycle with an eye to finding consistencies along with variation in first cycle Slaty-backed Gull. Kevin McLaughlin. Hamilton, Ontario, Canada.