MA - Slaty-backed again - 02/26

Slaty-backed Gull - 2nd/3rd cycle, Barton Cove, Gill, Franklin Co., MA.

Slaty-backed (2nd/3rd cycle), Great Black-backed, American Herring and Lesser Black-backed Gulls, Barton Cove, Gill. Image taken from Gill side though here the birds are in the middle of the channel.

Slaty-backed Gull - 2nd/3rd cycle (center), Barton Cove, Gill, Franklin Co., MA.

After gulling at Windsor Landfill, CT, I decided to take the long diversion home and call in at Barton Cove once again. No birders were present on the Gill side of the river when I arrived, maybe not too surprising in view of the appalling light and the presence of very few large gulls. Most of the ice had gone after a mild night and day, but a pocket remained very close to the dam and held just a handful of birds. By viewing through a chain-link fence I was able to get some moderately close views of the resting gulls and decided to concentrate my effort from here. Slowly more birders arrived, as did the larger gulls and it was one of my field companions who picked out the Slaty-back very close to us on the ice just before 5pm. Only seconds later, the gulls suddenly spooked and the Slaty spent the remaining time out in the middle of the ice free water close to Unity Park. Ironically, the views from Unity Park on this particular evening would have been very good. All the gulls flew up river without returning after an immature Bald Eagle passed through at around 5:20pm.

MA - SLATY-BACKED still present - 02/23

Another brutally cold evening at Barton Cove, Turner's Falls, but some really excellent gulling with seven species present. The Slaty-backed put on a fine show and was already present on the water at Barton Cove when I arrived at 4:10 pm. It then showed to a host of admirers until dusk, viewed mostly from Riverview Drive in Gill.

MA - SLATY-BACKED GULL, Turner's Falls - 02/20 and 02/21

Slaty-backed Gull - 2nd/3rd cycle (center). The first distant views from the boat launch off Unity Park, Turner's Falls, Franklin Co., MA. Feb 20th, 2009.

This 2nd/3rd cycle Slaty-backed Gull was discovered in the smallish gull roost at Barton Cove on the evening of February 20th with about 500 other large gulls present. Initially, I picked it up at distance resting on the ice near the dam viewing from the Turner's Falls side of the river . I drove around to Gill hoping for better views only to find the bird roosting until all the gulls were flushed by a Bald Eagle. The gulls then spent the next 30 minutes in the air and I didn't see the Slaty-backed again. I decided to hold back from making a full alert primarily because I hadn't seen all the critical features well enough to be certain of the identification.

On Feb 21st, I returned to the site along with Susannah Lerman, Nick Bonomo, Brian Kane and Scott Surner. It was actually Nick who spotted the bird first, just after a late arriving flock of gulls came in from the North shortly before 5pm. From that moment we had the bird in view and watched it from both sides of the river until we left at around 5:45pm.

Amazingly, this is the same individual Slaty-backed Gull that spent a week at the Windsor/Bloomfield Landfill during February 9th - 13th, which can be identified by comparing the plumage and bare part features here.

If accepted, I believe this will be the first record for Interior Massachusetts.

Slaty-backed Gull - 2nd/3rd cycle (center). Crop from the above shot off Unity Park, Turner's Falls, Franklin Co., MA. Feb 20th, 2009.

Slaty-backed Gull - 2nd/3rd cycle (center). Closer views from Riverview Drive in Gill, Franklin Co., MA. Feb 20th, 2009. The bird frustratingly roosted here until all the gulls got flushed by a Bald Eagle.

Slaty-backed Gull - 2nd/3rd cycle (center). Reasonable views at dusk from Riverview Drive in Gill, Franklin Co., MA. Feb 21st, 2009. Having seen the bird well in strong sunlight from the Turner's Falls side of the river we drove around to Gill around sunset and decent looks there. Glare can seriously hamper the viewing from Riverview Drive on a cloudless day as it was on the 21st.

CT - SLATY-BACKED GULL - 02/13

Another superb find at the Windsor Landfill. This 2nd/3rd cycle Slaty-backed Gull was found by Patrick Dugan and Frank Mantlik on Monday and has been seen somewhat frequently throughout the week.

I spent just 90 minutes at the landfill this afternoon and was quite overwhelmed by the huge numbers present. At least 6,000 large gulls were present when I first arrived. I eventually located the Slaty-backed at around 15:10hrs and watched it depart East at 15:15hrs. Plumage wise, it was quite a different beast to the bird found by Nick Bonomo in November 2008 being clearly younger.

It seems pretty incredible that this small inland landfill now has 2 Slaty-backed and 2-3 Thayer's Gulls to its credit, all from the same winter.




Please note that all of these images have been quite strongly affected by late afternoon glare. Conditions were not ideal.

Also at Windsor Landfill today, 1 Glaucous Gull (1st cycle), 1 Kumlien's Gull (1st cycle), 1 uid Kumlien's/Thayer's (1st/2nd cycle) and 1 Lesser Black-backed Gull (adult graellsii).

On the way home I spent 45 minutes at the Holyoke (MA) gull roost viewing North from the Rt 116 bridge over the CT River just below the falls. About 1200 gulls had gathered before I decided to leave with c.700 of these being Ring-billed. Most notably, 4 Kumlien's Gulls flew into the roost, down on last weekend's count of 10 birds, although I didn't stay for the late arrivals which has often brought in most of the Kumlien's at this particular site, with a high of 13 Kumlien's Gulls on January 30th. However, eight species of gull in an afternoon in the interior Connecticut River Valley can't be bad.

Other notable birds for the day included a fly-over Common Redpoll on North Whitney Street, Amherst and another visit from a green morph Pine Siskin to our feeders in Amherst.

A little more Slaty

Slaty-backed Gull - Windsor Landfill, CT. Nov 28th. Thought to be fourth-cycle. Potentially the first state record.

This fourth cycle Slaty-backed Gull at Windsor in Connecticut inspired much discussion on the ID-Frontiers listserve, especially concerning the bird's back color. By coincidence, the Ujiharas have just posted more fabulous shots of Slaty-backed Gulls on their wonderful Japanese Gull-site. They include this amazing image set of the same bird taken within a two minute period and have not made any adjustments to the images regarding brightness or contrast - the images are rather revealing. Enjoy!

On the same theme, here's an earlier post that I made on Slaty-backed Gull upperpart tones;
http://pioneerbirding.blogspot.com/2008/12/murky-shades-of-slaty.html

Murky shades of 'Slaty'.

Slaty-backed Gull - sub-adult (Kodak 9.5 - 11.5) with adult Great Black-backed Gull (Kodak 13 - 15), Windsor Landfill, CT. November 28th. The scoring system follows Howell & Dunn in 'Gulls of the Americas'.

This fine sub-adult Slaty-backed Gull, found by Nick Bonomo at the Windsor Landfill, CT on November 28th, has come under plenty of scrutiny since the images first appeared on the North American Stop Press page on Surfbirds.

Most of the debate has centered around the color of the upperparts and whether or not the mantle tone is dark enough for a 'pure' Slaty-backed Gull. Gary Rosenberg opened up the debate on the Identification Frontiers forum, resulting in an extremely interesting thread which you can follow by clicking here. I must confess that I came away from the Windsor Landfill with the feeling that I'd seen a pretty normal Slaty-backed Gull, ie. a large dark-mantled gull showing all the criteria that one might expect for a solid 'Slaty' claim by one of Connecticut's sharpest birders.

So what's going on? The big question seems to be orientated around the judgment and appearance of gray tones in digital images, taken by a range of photographers using different photographic equipment and viewed on computer screens. This comes as a big surprise, because I'd assumed that the 'dangers' of trying to accurately assess gray tones both in the field and from digital imagery had been widely accepted for some time. Very unfortunately, the assessment of mantle color by the field birders on the ground seems to carry little weight in the argument and questions over the apparent 'paleness' of this bird continue.

The Kodak Gray Scale has become the standard scoring system for the very difficult job of attempt to assess the back color of gulls. Just focusing (for the moment) on the scores used in the most recent publication on gull identification "Gulls of the Americas" by Steve Howell and Jon Dunn, I thought it would be a useful reminder to compare back (mantle and scapulars) colors with several of the Slaty-backed Gulls that I've seen over the last two years to see how they measure against more familiar species present in the same images.


Howell and Dunn offer the following rough guide;
Kodak 3 - 6 is pale gray.
Kodak 6 - 8 is medium gray.
Kodak 8 - 10 pale slaty gray.
Kodak 10 - 12 slaty gray.
Kodak 12 - 14 dark slaty gray.
Kodak 14 - 17 dark slaty black.

They state that "most taxa are fairly consistent in the gray shade of their upperparts" and only vary by 1 to 1.5 Kodak values. They offer several useful tips such as "bluer hues tend to make grays look lighter and browner hues can create darker tones", and advice on the best conditions for 'gulling' and back color assessment; "high overcast or partly cloudy skies". So with these factors in mind, here's an image selection drawing comparisons between familiar and rarer species and the Kodak Gray Scale scores referenced in Howell & Dunn 2007.


Lesser Black-backed Gull L.f. graellsii (Kodak 9 - 11) adult at rear with adult Ring-billed Gulls (Kodak 4 - 5), Amherst, MA. October. My personal assessment of the back color of the CT Slaty-backed was about the same as an average graellsii Lesser Black-backed Gull. Some birders present at the scene thought it was a tad lighter, but not by much. NB. A score of Kodak 9 would be an extreme light graellsii.

Lesser Black-backed Gull L.f. graellsii (Kodak 9 - 11) adult/sub-adult with American Herring Gulls (Kodak 4 - 5),


Slaty-backed Gull - sub-adult, Nome, AK. June 26th, 2008. (Kodak 9.5 - 11.5).


Slaty-backed Gull - second/third-cycle, St. Paul Island, AK. June 28th, 2008. (Kodak 9.5 - 11.5)


Slaty-backed Gull - third cycle (Kodak 9.5 - 11.5) with adult Mew Gulls (Kodak 6 - 7.5), Nome, AK. June, 2008.


Vega Gull - second/third cycle (Kodak 7 - 8), Nome, AK. June 2008. Back color rather darker than American Herring Gull (Kodak 4 - 5).

Slaty-backed Gull - adult (Kodak 9.5 - 11.5), Rochester WWTP, NH. January 10th, 2007. Sub-adult Great Black-backed Gull ((Kodak 13 - 15) at rear, surrounded by adult American Herring Gulls (Kodak 4 - 5). Taken on a bright sunny mid-winter morning.

Slaty-backed Gull - adult winter (Kodak 9.5 - 11.5), Rochester WWTP, NH, with American Herring Gulls (Kodak 4 - 5). Same as above, January, 2007. Compare with the Massachusetts SBGU below, one year later in January 2008.


Slaty-backed Gull - adult (center). In this shot appears almost as dark the two swimming adult Great Black-backed Gulls. t Using Kodak scoring system this Slaty-backed should represent the extreme dark end(K 11.5) of the range of variation to appear so close in tone to these adult Great Black-backed Gulls (extreme light would be K13). January 2008. Compare with the New Hampshire SBGU above. This SBGU was photographed on an overcast day.




Slaty-backed Gulls - worn adult (Kodak 9.5 - 11.5) lower left in both shots, with Glaucous Gulls presumed barrovianus (Kodak 4 - 5), and third cycle Slaty-backed Gull (top left in both shots). Nome, AK, June 2007.


Kamchatka Gull - adult/sub-adult (Kodak 6.5 - 8) with Ring-billed Gulls (Kodak 4 -5). Rhode Island, January 2006.

In summary, I remain happy with my field assessment of the back color of the CT Slaty-backed, placing it as being extremely close to an average graellsii Lesser Black-backed Gull. This would give the CT bird a score of around K 9.5 or 10, perhaps light for some SBGU but certainly not enough to cast doubt over the identification based on a single feature. Looking at my images from Massachusetts last winter, and some of those coming from Newfoundland, it's also rather clear that some variation in plumage types (light and dark) is evident in the vagrants turning up in the North-east. At the moment, variation in SBGU seems to be poorly understood with question marks being placed against extremely light birds as well as extremely dark birds, but birds which otherwise shows a perfect suite of characteristics for our current understanding of SBGU. The variation needs to be explained and I'm hoping to follow up on this fascinating story when more clear information comes to light.

Happy gulling,

JPS.

CT - SLATY-BACKED GULL - Nov 28th

Thanks to a timely and much appreciated phone call from Nick Bonomo, my visiting parents and I drove down to the Windsor/Bloomfield landfill to enjoy this fantastic find by Nick. Leaving the house to the site took just fifty minutes, straight down I-91.

On arrival, the bird was out of view for the first twenty minutes or so causing me to keep glancing at my watch and worry about closing time (4pm). At around 2:25 pm I re-located it and then had it view until 3:05pm, along with a relatively small band of very happy birders. At peak, I would say some 5,000 large gulls were present on site at around 2pm but a gradual thinning of birds was evident throughout the afternoon leaving perhaps less than 2,000 by about 3:45pm when we departed.

This Slaty-backed Gull is certainly showing some signs of immaturity, most obviously in the dark bill markings and has me wondering about the age which I'll discuss when I have a little more time. Nick is discussing the age of the bird on his own blog here.

A very cool find indeed that gives me some hope for the forthcoming winter evenings at Turner's Falls.









Slaty-backed Gull - 3rd/4th cycle - The first record in Connecticut.


Slaty-backed and Kumlien's Iceland Gulls flanked by American Herring and Great Black-backed Gulls.


Kumlien's Iceland Gulls - about 4 present at the landfill today.


Lesser Black-backed Gull - adult with primaries still growing.

Slaty-backed selection - 01/17

Lovely shot of the much quoted 'String of pearls' effect.

Compare upperparts tone between Slaty-backed Gull (left) and Great Black-backed Gull (center).

What a day it was to be at Niles Pond on Eastern Point, Gloucester. Huge numbers of gulls resting and bathing, many of them close. This adult Slaty-backed Gull was among them looking quite awesome where ever he placed himself, spending at least two and a half hours on Niles Pond today. My last images were taken at 14:55hrs.

This bird looked significantly darker above and much more heavily blotched and streaked than the adult that I saw here on January 10th. At the moment, I'm not that convinced that it's the same bird.

Beyond the Slaty-backed, the rest of the gull show was mightily impressive with over 50 Kumlien's Gulls, about 4 Thayer's (all first-cycle at fairly close range/photo'd) and 5+ Glaucous Gulls. Hybrids included 2+ Nelson's Gulls and a possible Lesser Black-backed x American Herring Gull (third-cycle bird). More on that one in another post, along with a very interesting adult Kumlien's/Thayer's.



All in all, another very rewarding half-day spent at Niles Pond.



JPS.