24 March 2015

More Photos of Lake Michigan's Putative Chandeleur Gull

I had completely taken the presumed Chandeleur Gull (Herring x Kelp hybrid) that spends its winters between Berrien County, Michigan and LaPorte County, Indiana, off my radar for the season. Having last seen it on Thanksgiving Day 2014, I was very happy to happen upon it on Sunday while gull-watching from the pier at the harbor mouth in Michigan City.

Putative Herring x Kelp ("Chandeleur Gull"). Michigan City, IN. 22 March 2015.
The bulbous-tipped bill is seen well here as is the thickness to the whiter trailing edge on the outer secondaries.

Back in late November, it was still molting its outer primaries and secondaries:

Michigan City, IN. 27 November 2014.
Note that the outer greater primary coverts still show black streaks, despite this bird showing an otherwise definitive adult plumage (as was the case in October 2013). I think it's safe to say that the small white mirror on p10 is a direct influence from its Kelp ancestry, as is the extensive black on both webs of p8-p10.

I can't think of any other instance that I've observed an adult gull with black subterminal marks all the way down to the first primary.

Note the apparent thickness of the trailing edge to the secondaries, and much more interesting, the wide white tips to the inner primaries. It is known that adult Slaty-backeds show these deep white tips to the inner primaries (deeper than what is seen here), but an extensive photo study online has taught me an excellent lesson: adult Kelp Gulls can show very broad trailing edges as well as thick white tips to the inner primaries (see here for an extreme example). This is a bit different on presumed hybrids with Great Black-backed influence.

Yellow-green leg color with grayish tones points away from two pink-legged parents (i.e., Herring x GBBG).
Flesh-colored feet is something I've regularly noted on yellow-legged adults (such as Yellow-footed Gull, Lesser Black-backed and Ring-billeds).
Shows a somewhat broad secondary skirt and relatively long legs. 
I will reiterate my conviction that Chandeleur Gulls are a "legitimate" hybrid form. I don't find it difficult to believe that Kelp Gulls, which are generally expanding north, and Herring Gulls, which are generally expanding south, have converged again in small numbers somewhere in the Gulf Coast/Caribbean. You can read more of my thoughts on this here.

22 March 2015

Thoughts on Pink Ring-billeds

They're back...
Ring-billed Gull (adult). Cook County, IL. 21 March 2015.
Pink adult Ring-billeds have returned to northern Illinois. The two working-theories are, 1) This pink hue is diet-related and that these birds may have spent their winters south of us (Gulf Coast region?) stocking up on astaxanthin, or 2) This pink hue is an external colorant caused by exposure to the large ore piles where these birds nest.

Interestingly, in my 6 years of careful observation of these individuals, it seems much more likely that pink birds pair up with pink birds - at least this is what is apparent while some 400 adults courting and establish bonds near my home in northern Illinois. Of these 400 adults, approximately 5% show some amount of pink in their plumage. Could it be that pink birds attract pink birds, or could it be that they're now staking out nesting sites on the ore piles in East Chicago? Hence, birds that are paired up may be exposed to the slag simultaneously, while birds not nesting on the ore piles remain white and tidy.

The latter theory may be supported by the fact that these "pink" individuals become more pink in April and May, suggesting their roosting/nesting sites continue to leave them with ongoing exposure to the ore piles/dust. Although one has to wonder why their legs and bills aren't tinged with pink if this coloration is due to ore piles! Do they do that well of a job of bathing their bare parts?

I was told by birders in California, Montana, and Pennsylvania that they're now seeing pink RBGUs too. Strangely, Cleveland lakefront birders don't see Ring-billeds that look like this. Lots of questions and I've never been more unsure about this phenomenon as I am this year.

Please send me any photos or comments on these pink Ring-billeds should you have any! Thanks.

16 March 2015

Adult Lesser Black-backed with White Tip to P10

Winter gull season is winding down here on southern Lake Michigan, evidence by the large exodus of American Herrings which have mostly been replaced with Ring-billed Gulls. Adult Herrings that do breed in the area have already picked out their nesting spots. For instance, the very small colony that breeds on the industrial building at Waukegan Harbor was already collecting nesting materials on Saturday.

Overall, the weekend was pretty uneventful, but I did manage an adult Thayer's and adult Lesser Black-backed.

Thayer's Gull (adult). Waukegan, Illinois. 14 Mar 2015.

Thayer's Gull (adult). Waukegan, Illinois. 14 Mar 2015.
The adult LBBG was definitely the highlight on Saturday, showing an all-white tip to P10, a mirror on P9 and a partial subterminal band on P5:

LBBG (adult). Libertyville, IL. 14 Mar 2015.
From the hundreds of adult LBBGs that I've seen, I've only observed an all-white tip to P10 twice before this. European gull aficionado, Mars Muusse informed me of just how rare this pattern is, with only 6 out of 931 (~ 0.6%) showing this in their sample of adult males and females combined.

Miscellaneous Herring Photos:

Photo 1 of 2.

Photo 2 of 2.

Photo 1 of 2.

Photo 2 of 2.

10 March 2015

Druid Lake Gulls: Baltimore

An unexpected trip to the Baltimore area allowed for a few hours of gull patrol last weekend. Druid Lake adjacent to the Baltimore Zoo had the most interesting gull congregation in the area:
  • 350 Ring-billed Gulls (7:1 first cycles to adult types)
  • 16 Great Black-backeds (all ages)
  • 7 Herring Gulls (1 first cycle and 6 adults)
  • 1 Lesser Black-backed Gull (3rd cycle type)
  • 1 Bonaparte's Gull (adult type)
The Ring-billeds were noticeably restless and much more active than my local RBGUs are at the time. Here's a goregeous 1st cycle that sat patiently for us:

Ring-billed Gull (1st cycle). Baltimore, MD. 07 March 2015.

01 March 2015

First Day of March: Glaucous & Great Black-backeds

I worked a few sections of the Calumet River in Chicago today (01 March 2015). 12 GBBGs and 5 Glaucous Gulls made up for the lack of Thayer's (1), Kumlien's (0) and LBBGs (0). I'm thinking some of our gulls must have moved on, likely to some of the dams and open rivers to the south.

Great Black-backed Gull (1st cycle).
Great Black-backed Gull (1st cycle). A rather dark bird holding on well to its juvenile neck, breast and flank feathers.
Two 1st cycle GBBGs and a 2nd cycle GBBG (back right). Did you notice the Glaucous Gull back there?
I ended up doing very little photographing and decided to spend a good chunk of time recording Herring calls (which are now becoming more and more vocal as the hours of daylight lengthen). In the process, I was pleased to get ~25 seconds of a 1st and 2nd cycle Glaucous both calling, in tandem, with a 1st cycle Great Black-backed. Glaucous Gulls - despite their bigger size - sound surprisingly similar to Herring Gulls. Great Black-backeds are in a class of their own.

Glaucous Gull (2nd cycle).
Glaucous Gull (1st cycle). Outer primaries worn and bleached (see below).

Inner primaries show brown markings that are consistent with the rest of the plumage.
The Outer primaries appear bleached and more worn.
This image is unquestionably underexposed  (to help capture the GLGUs). The snow also does a good job of tricking the camera's metering system which in turn makes the Herring Gull look extra dark - no it's not a Vega Gull :).
The 2nd cycle Glaucous on the right would not stop bullying everything around it - except for one large, presumably male, GBBG.
Herring Notes:

This 2nd cycle type is sporting a few adult-like rectrices. My guess is somewhere along the line, a few feathers were ripped out and then readily replaced. Tail and flight feathers are commonly tugged at during fights with congeners.

Herring Gull (2nd cycle type).
Next up is a 2nd cycle showing uniformly colored upperparts:

Herring Gull (2nd cycle).
Here it is in flight with a 1st cycle Great Black-backed:

If the inner primaries were any darker, you might start to suspect a LBBG.
Adult type Herring Gull. Shows little white mirror on p9 and small black spot on outer edge of p4.
I imagine this wingtip pattern is age-related and likely represents a young adult. 
Herring Gull (3rd cycle type).
Herring Gull (2nd cycle type). The contrasty upperparts make for a really neat-looking seabird...

28 February 2015

February 2015 Quiz

Pointed primary tips with relatively crisp and checkered upperwing coverts readily age this bird as a first cycle. It's obviously bigger than the medium sized Ring-billeds in the background, so the default large white-headed gull to begin with would be American Herring. This taxon has a range that's more widespread than any other North American gull. It would behoove anyone with a serious interest in gull identification to become intimately familiar with Herrings.

The majority of participants nailed this month's quiz, but a fair number of participants - perhaps unsurprisingly - answered Thayer's Gull. The overall pale and uniform coffee-color to the upperparts, and pale-tipped primaries do bear a superficial resemblence to Thayer's.

It's not, however, uncommon for 1st cycle Herrings to show pale chevrons on the tips of the outer primaries. When Herrings do show this pattern, the pale color is typically restricted to the very tips of the primaries and not as encompassing as in Thayer's (which shows pale edges coming up towards the sides of the primaries - here's an example).

Other features that favor a 1st cycle Herring Gull is the paling bill base and smokey gray upper mantle. Although this aspect isn't unheard of with Thayer's, it's much more common with Herrings.

Monthly Notables February 2015

February 2015
  1. Black-legged Kittiwake (1st cycle). Mohave County, Arizona. 01 February 2015 (under 20 state records).
  2. Slaty-backed Gull (adult). Santa Clara County, California. 03 February 2015.
  3. Iceland Gull (1st cycle). Rutherford County, Tennessee. 03 February 2015 (6th state record).
  4. Slaty-backed Gull (adult type). Cook County, Illinois. 07 February 2015 (6th/7th state record).
  5. Mew Gull (2nd cycle type). Brooklyn, New York. 09 February 2015 (5th state records).*
  6. Vega Gull (adult type). Brownsville, Texas. 21 February 2015 (5th state record).**
  7. Great Black-backed Gull (1st cycle). Tulsa, Oklahoma. 25 February 2015 (under 10 state records).
* Apparent North American "Mew" or Short-billed Gull (L.c. brachyrhynchus).
**Regarded as a subspecies of Herring Gull, L.a.vegae, by the AOU. 

22 February 2015

Calumet River: 3rd Cycle Kumlien's & Adult Glaucous

I spent a few hours on the Calumet River in southeast Chicago this morning. I again failed to relocate the adult type Slaty-backed from a couple of weeks ago. The quick and distant glimpses that I got of it on 12 Feb 2015 were bittersweet, but I'm still hopeful that I'll get some full-frame shots before the end of winter.

We managed to see all of our winter gulls today: Thayer's (4), Kumlien's (1), Glaucous (2), Lesser Black-backed (1), and Great Black-backed (6). These were hard-earned birds in biting-cold conditions: ~20F with a 10-15 mph north wind directed at our faces. Birders who joined me for part of my 3.5 hour session were Andy Sigler, Greg Neise, Wes Serafin, Sue Friscia, and Dave Gruver.

As usual, I'll start with my favorite bird of the day:

Kumlien's Gull (3rd cycle type). Chicago, IL. 22 Feb 2015. Photo 1 of 4.
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Next up was a purty 1st cycle Thayer's/Kumlien's type, tending towards Thayer's:

Thayer's Gull (1st cycle). Chicago, IL. 22 Feb 2015. Photo 1 of 3.
Showing a fault bar across the subterminal portion of the rectrices. 2 of 3.
3 of 3

This adult Thayer's cooperated nicely:

Thayer's Gull (adult). Chicago, IL. 22 Feb 2015. Photo 1 of 3.
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3 of 3

Adult Glaucous Gulls are never dull...

Glaucous Gull (adult). Chicago, IL. 22 Feb 2015.
Some black-backeds...

Great Black-backed (2nd cycle). Chicago, IL. 22 Feb 2015. Photo 1 of 3.
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Great Black-backed Gull (adult). Chicago, IL 22 Feb 2015. Photo 1 of 2.
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Lesser Black-backed Gull (adult - correction: sub-adult type). Chicago, IL. 22 Feb 2015. Photo 1 of 3.
2 of 3
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A sub-adult Bald Eagle was moving overhead just as Greg and Andy arrived...

It's typical for all of the gulls to flush when an eagle comes down the river, and they do! But for a second time in my life, I've now seen another Herring Gull tangle with a Bald Eagle. Today, a 2nd cycle type ascended high into the sky as it tailed a young Bald Eagle and continued to quickly fly at it and escort it higher and higher away. The eagle never pursued the Herring and continued on...I found this behavior to be very interesting.

Speaking of interesting Herrings, here's a gorgeous 3rd cycle type that has retained a good amount of black on the bill:

Herring Gull (3rd cycle type). Chicago, IL. 22 Feb 2015. Photo 1 of 4.
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Overall, a pretty productive day despite our freezing digits and runny noses...

 Winter is passing...but nowhere near vanishing!