Saturday, April 14, 2018

The end of the gulling season?

I had Tuesday, April 10th, off from work and the weather was crap. Cold and wet. It's been the theme of the "spring" so far.

Loads of gulls still around, so I spent a few hours in the afternoon specifically seeking out Bonaparte's Gulls in search of a Little Gull. I hadn't seen a Little Gull in CT in three years, so I was due and didn't want to miss again this year. Their window of passage has narrowed over the years and now they are almost exclusively seen during the first half of April. They used to be more spread out through March into April. Now they're rarely seen in March at all.

I came across Bonaparte's Gulls at four locations along the coast, the last of which held a good 75 or so birds. No sign of any Little Gulls when I arrived, but I would walk onto the flats and hang out for a bit since this would be my last stop. Soon there happened to be a slight turnover of Bonaparte's...several took off, while some flew in from Long Island Sound to bathe and preen. All of a sudden standing at the edge of the water was an adult LITTLE GULL. I have no idea how and when it slipped in. Did I really miss it fly in, or had it been hiding behind some roosting gull the entire time? I'd bet on the former, but can't be sure.

After watching from a distance for a few minutes, the bird unexpectedly picked up and flew much closer to me, allowing for some photos before I was chased back to my car by a sleet squall.



Little Gull, adult beginning prealternate molt

The bird had a subtle but noticeable peach wash on its belly. The hood was just starting to molt in, but the dominant markings on its head were the dark "ear spot" and the smudgy dark cap typical of basic plumage.

This put a great cap on the afternoon, which also featured a GLAUCOUS GULL and a first cycle ICELAND GULL that I don't think can comfortably be placed into either kumlieni or thayeri. Somewhere between the two. Who knows.





a tweener Iceland Gull

Later in the week, we finally surpassed 60 degrees (even 70). I took a run through many of these same areas on Friday afternoon to find that gull numbers were way down. That is likely the end of the plankton-induced gull bonanza of 2018 in Long Island Sound. It's still not too late to get out there and see gulls, but we are officially past peak now. It really tends to drop off hard come mid-April.

 - Nick

Monday, April 9, 2018

2018 COA Gull Workshop (a 'thayeri' Iceland and ten thousand other gulls)

On Saturday, April 7th, some 45 birders attended COA's annual Gull Workshop. At Stratford Point I gave a presentation on gull ID that was followed by a field session. During a break in the indoor segment, Stefan Martin relocated a thayeri-type ICELAND GULL that Patrick Comins had found the previous day. It was part of a small flock of gulls that were scraping recently-attached barnacle larvae off the rocks at the point.









I had expected that we would be running up and down the coast in search of these wandering plankton-feeding flocks, but as it turned out, we never had to leave Stratford. The field session started at the Seawall, where a couple of flocks began plankton-feeding close enough to shore for study. Bonaparte's Gulls were scattered among the abundant Ring-billed and Herring Gulls, and we had upwards of 10+ of our standard kumlieni Iceland Gulls in the area at once. The first cycle "Kumlien's" Gulls are bleached pretty much white by this point in the season. It's been a great winter for those white-wingers, so there have been plenty around to study. The same first cycle thayeri from the point reappeared in one of these flocks, looking quite different from the kumlieni with its well-retained brown in the primaries, secondaries, tertials and tail despite the date.


Everyone enjoyed nice scope views of these birds as they picked at the floating larvae. We were able to chum in a few birds too, including this kumlieni Iceland. Note the bleached white upperparts of this bird, typical for this age in early April.





We lingered at the Seawall for much longer than expected. Why leave with so many birds around? We scanned in vain for a Little or Glaucous Gull. Sometime during early-mid afternoon, after the crowd had thinned, we moved to Long Beach for a different viewpoint. The flocks eventually coalesced offshore here, where numbers peaked at a whopping 10,000 or so gulls. The spectacle was something to see.

A small fraction  of the action

It seemed that our participants really enjoyed the variety, the views, and the sheer spectacle. We put our ID skills into practice and even tried our hand at ageing some birds. I was really impressed by the enthusiasm of the group. We really hit the jackpot as far as finding so many birds to study for such a prolonged period. We got lucky. Even during the peak of this annual event, you sometimes have to spend hours either working up and down the coast to find the flocks or just waiting for them to come to shore after feeding a mile offshore. The waters off Long Beach at the end of the day honestly might have held as many gulls as I have personally ever seen at one time in Connecticut.

We are almost at that time of year when this event ends and most of the birds move north, but we may be peaking a bit later this year. The consistently below-average temps and inclement weather may have something to do with that. We're finally getting a warm spell this weekend, which could clear many of these birds out. I'm going to try to enjoy this event a bit more before it's over.

 - NB

Sunday, April 8, 2018

A Fun Flock of Gulls

Today between errands I stopped by the Oyster River mouth in Milford/West Haven, CT as I do often this time of year. The gulling at this location this season has been inconsistent, so I was pleased to find about 600 birds roosting on the flats at low tide today. It turned out to be a really fun flock to sort through. Nothing super rare, but a bit of variety and some really fascinating individuals.

We'll start with the anomalous Ring-billed Gulls.

First, the dark first cycle. Black legs, black-and-yellow bill, dark plumage aspect. Probably the coolest-looking Ringer I've seen in person. Vaguely reminiscent in some ways of "Picasso," a presumed screwed-up RBGU that was seen in the northeast a couple years ago. (Trying Facebook link...may or may not work.)










Next, the leucistic one. This bird is just as confusing to me, mostly because I'm having trouble ageing it. I first saw what I assume to be the same bird exactly two years ago, in early spring 2016, about a mile down the coast at Bradley Point. It was not cooperative on that frigid windy day, but I got a few record shots.

Early April 2016 (Bradley Point, West Haven):
Obviously the bird is overall pale with brown in primaries where black should be, and not at all an adult-like primary pattern. There is brown on the primary coverts and alula. Still, note all the adult-like features: eye color, bill color and pattern, leg color, white tail.





I didn't notice it last year, but have seen it twice over the past month. First at the same spot as the original sighting (Bradley Point), and then again today at nearby Oyster River.

March 17, 2018 (Bradley Point, West Haven):
This year, the bird has a more advanced primary pattern, but still not adult-like, including retaining brown on the primary coverts. Strange. If it wasn't a full adult two years ago, it sure should be by now...





April 8, 2018 (Oyster River, West Haven/Milford line):





This RBGU was leg-banded. Read in the field and reported. Funky left eye on this bird, at which I didn't take a second look since I was focused on others at the time.

X7U on right leg

A first cycle LESSER BLACK-BACKED GULL was in the group. A hefty individual.





first cycle Lesser Black-backed Gull

A rather white first cycle "Kumlien's" ICELAND GULL made an appearance; this is what the overwhelming majority of local first cycle Iceland Gulls look like by early April [=bleached].


first cycle "Kumlien's" Iceland Gull

This flock also held a few BONAPARTE'S GULLS, though not nearly as many as one would expect on this date. Six species plus a few oddities made this a pretty fascinating couple hours at this tiny "river" mouth. Hardly surprising, though...I've personally seen a dozen gull species there. Oyster River is one of the premier gull-watching locations in the state, and it really tends to shine this time of year.

Bonaparte's Gulls

 - Nick

Thursday, March 8, 2018

A Northern Shrike in Japan

I’m recently back from two weeks in Japan with Julian Hough and Dave Provencher. We had a blast and saw heaps of great stuff. Over the next several weeks I hope to roll out at few posts related to that trip…some ID stuff, and some basic trip report stuff. Fixing the formatting on this blog is also something I'd like to get around to.

One of the locally scarce birds we were lucky to see in Japan was this Northern Shrike on Hokkaido. In speaking with an experienced local, they are just about annual. We had two encounters with the bird. On our second visit we were able to secure photos, including a couple of in-flight shots. These are heavily cropped and unedited.







The Holarctic “northern gray shrikes” underwent a bit of a taxonomic shakeup in 2017. Per the AOS, they were split into Northern Shrike and Great Grey Shrike. But the line drawn was not a clean North American versus Eurasian split as one might have assumed it would be. Rather, the East Asian form(s) were combined with the North American form(s) to be called Northern Shrike (Lanius borealis), while the central and western Eurasian forms are called Great Grey Shrike (Lanius excubitor). So there is a line drawn somewhere on the Asian mainland. Shrike taxonomy is rarely straightforward.

Here is a summary of relevant field marks on our bird:

-        Thin, short white line above the eye between the black mask and gray crown. This line is subtle and short, occurring only above the eye and slightly behind it.

-        Small white patch at base of primaries, best seen in flight

-        No white spotting at base of secondaries

-        R6 appears mostly white with a black wedge at its base

-        Vermiculations on the breast/belly are absent or, at best, very faint and not visible due to image quality

-        Narrow dark lores

-        No white spot on lower eyelid

-        The rump is not seen clearly, but seems to be some shade of gray fading to paler gray/whitish


Open wing and tail photos are helpful when trying to separate certain shrike taxa. First, it is worth ruling out Great Grey Shrike, as unlikely as that would be…but vagrant shrikes are very much a thing. In my cursory review of Great Grey Shrike images combined with a couple internet and book references, it appears that Great Grey Shrikes show at least SOME white on the secondaries (anything from a narrow line to a large patch), while Northern Shrikes do not. Our bird’s white patches are restricted to the primaries. There is no white line at the bases of the secondaries.


This image is borrowed from the paper "The Northern Shrike Lanius borealis sibiricus Bogdanov, 1881 (Aves: Laniidae) in Ukraine: a taxonomic assessment" by Svetlana ├Ť. Tajkova & ├éroslav A. Red’kin

There are probably three subspecies of Northern Shrike that are reasonably in play here:

L. b. sibiricus – The widespread Siberian form. Per Mark Brazil’s Birds of East Asia, this form winters rarely to Hokkaido.

L. b. bianchii – Apparently breeds on the Kuril Islands (which are visible from Hokkaido!). Per Brazil and Birds of North America Online, this form winters south to Hokkaido. It seems that this form isn’t terribly well known, which is not surprising given its location and restricted range.

L. b. borealis – The North American form, and presumably the least likely to occur on Hokkaido. This form breeds as nearby as Alaska and is migratory/irruptive (they all are).


Obviously the two Asian forms are far more likely than the North American form (borealis). I do not know if borealis has ever occurred in Japan.

This figure is also borrowed from Tajkova & Red'kin. Note the position of bianchii in relation to borealis and sibiricus, and that Northern Shrike and Great Grey Shrike are not each others' closet relatives.

There is some contradiction in the literature on how to separate borealis from sibiricus, which makes this task more difficult. For instance, Pyle states that sibiricus often has some white at the base of the secondaries (contrary to the above screenshot from the Ukrainian paper), and that sibiricus has an entirely white r6 (the only source I found that claims this). Using that criteria, our bird would not fit sibiricus very well. However our bird’s lack of obvious ventral vermiculations and lack of white spot on lower eyelid are pro-sibiricus, per Pyle.


Borrowed from Pyle's fantastic Identification Guide to North American Birds, Vol 1


To confuse things a bit more, this Western Birds account essentially quotes Pyle, but there is a typo in the borealis section, which here states that borealis should have white at the bases of the secondaries. Oops.



Here is what Brazil’s field guide has to say. He addresses bianchii in the text.




The picture did finally clear a bit when I checked the Birds of North America Online account, which is thorough and addresses all relevant forms.




There is some contradicting information between the above sources, and certain field marks noted by some sources are not mentioned at all by others. Clearly this is an identification that is being worked out, if it can even be done with confidence in the field.

An eBird search of Northern Shrike images from Alaska (presumed source of potential vagrant borealis to Japan) reveals that adult-like birds indeed average a more extensive white border between the gray crown and the black mask than our bird shows. It appears like more of a white line above the entirety of the mask in the Alaska birds, while our bird really just shows narrow white above the eye with only a bit extending behind. The ventral barring also seems to be readily visible on the AK birds, which reflects my personal field observations with eastern US/Canada adults. A couple of those photos of Alaskan adults show little/no vermiculation below, but this may be wear-related as those images happened to be taken during summer.

Here are my current thoughts on this bird from Hokkaido. I don’t think it is borealis. Two of the few things that most of the sources seem to agree upon are the presence of a more obvious white supercilium on borealis combined with more obvious ventral barring. Our bird does not fit that description. Add that borealis would be a vagrant to these parts, and we are probably dealing with one of the expected Asian forms.

Which Asian form? Don’t know. As little as I have been able to learn about sibiricus, I know even less about bianchii. It may be significant that this bird didn’t seem to show much (any?) ventral barring, which according to BNA may be pro-bianchii.

If anybody has anything to add or correct, please do. Thanks!

- Nick


References

Brazil, M. 2009. Birds of East Asia: China, Taiwan, Korea, Japan, and Russia. New Jersey: Princeton University Press.


Cade, T. J. and E. C. Atkinson. 2017. Northern Shrike (Species Account). Birds of North America Online. The Cornell Lab of Ornithology.

Gibson, D. D. and J. J. Withrow. Inventory of the Species and Subspecies of Alaska Birds: Second Edition. Western Birds 46(2):94-185.

Pyle, P. 1997. Identification Guide to North American Birds: Part 1. Bolinas, California: Slate Creek Press.

Svensson, L., K. Mullarney, and D. Zetterstrom. 1999. Birds of Europe: Second EditionNew Jersey: Princeton University Press.

Tajkova, S.U, and A. A. Red'kin. 2014. The Northern Shrike Lanius borealis sibiricus Bogdanov, 1881 (Aves: Laniidae) in Ukraine: a taxonomic assessment. Journal of the National Museum 103(8):89-107.