26 December 2012

Hammond Kumlien's Returns

Since at least 2009, this adult Kumlien's Iceland Gull has returned to the same marina to spend its winters. Most interesting is that it holds a strict winter territory similar to a raptor. It perches atop a "No Wake" sign at the harbor mouth and does not associate with the other gulls. In fact, any gull that enters the harbor mouth is swiftly chased off by this northern beauty:

Adult Kumlien's Iceland Gull. Hammond, IN. 24 December 2012.

11 December 2012

More Intermediate Thayer's/Kumlien's and a 2nd Cycle Thayer's

Greg Neise and I teamed up for some Lake County gulling on Saturday. We hit the LC Fairgrounds first where we were treated to this:

Adult Kumlien's. Lake County, IL. 08 December 2012.
We went back and forth about the possibility of it being an intermediate Thayer's/Kumlien's, and although it may be, I leaned towards Kumlien's because of the limited markings on the primary tips, but especially because of the unmarked P5 - this has not been documented in the leading identification papers on Thayer's Gull:

Note the large, all white, tip to P10 and unmarked P6. This individual exhibits a pattern similar to PLATE I in Howell and Dunn, but the shade of darkness is much more extensive.
We then headed for North Point Marina, running into some nasty snow/rain mixture along the way, but just as we were approaching our destination, the rain stopped and it cleared up with partial sunshine!

We found 2-3 Kumlien's types and 2-3 Thayer's - no Glaucous or LBBGs,  which was somewhat of a surprise.

2nd cycle Thayer's Gull. Lake County, IL. 08 December 2012.

Although P10 is with a large white tip, P6 is with a full subterminal band. This individual resembles PLATE P in Howell and Dunn. I thought it was best to keep this one in the "intermediate" category, but to my eyes, the under pattern suggests Thayer's.
We also had this beast of a 2nd cycle Herring with an almost completely unmarked bill:
The adult-like bill pattern is just another example of the infinite variation found at the species level with Herring!

03 December 2012

Pinkish Bills in Adult-like American Herrings

Here's an adult-type American Herring with a mostly pink bill:

Milwaukee, WI. 02 December 2012.
The visible primaries have a perfectly looking adult aspect and the upperparts appear solidly gray, but the bill pattern suggests a sign of immaturity.

Here's what the open wings and uppertail look like:

Note the dirty alula and marked rectrices. This individual is not a definitive adult, but rather, a 4th cycle bird.

Also of interest are the bold black outlines to the shafts of the the primaries and greater primary coverts. Is this another sign of immaturity?

01 December 2012

Apparent Tone in Blackish Wingtips and Angle of Observation

It's no secret that a single photo of a gull at one point in time can be very misleading. This post is just another example of that. Specifically, note how the apparent shade of this bird's wingtips go from "sooty black" to nearly "jet black" depending on its angle to the observer:

Adult Thayer's/Kumlien's type. Lake County, IL. 21 November 2012.
This seems like a common problem with Thayer's/Kumlien's types and Glaucous-winged hybrids such as this individual:

Adult Glaucous-winged hybrid (GWGU x WEGU or GWGU x HERG). Gray's Harbor, WA. January, 2012.
Note the "apparent" change in lighting. This is due to a slight change in angle (by both the observer and the bird). In the top photo, I observed the bird on my right, slightly from the front. In the bottom photo, the bird is now slightly to my left, viewed from behind. There was no change in environmental conditions or camera settings in these two photographs.The overall effect on the wingtips is dramatic and likewise on the gray upperparts.  
Ultimately, I think it's safest to make an assessment of wingtip coloration in profile; preferably using a known species for side-by-side comparison.

23 November 2012

First Thayer's of the Fall and More LBBGs - 2012

I went up to the Lake County Fairgrounds in northeastern Illinois this morning. There was a good presence of Thayer's Gulls (5) and Lesser Black-backeds (8). Best of all, birding was from the car which made the 30 mph winds a bit more tolerable.

Adult Thayers with adult LBBG. Lake County, IL. 23 November 2012.
First cycle LBBG. Lake County, IL. 23 November 2012.
2nd Cycle LBBG. Lake County, IL. 23 November 2012.
4th Cycle LBBG. Lake County, IL. 23 November 2012.
Adult LBBG.  Lake County, IL. 23 November 2012.
Adult Thayer's Gull (front) with American Herring Gulls. Lake County, IL. 23 November 2012.
Adult Thayer's Gull with Herrings in background. Lake County, IL. 23 November 2012.
Adult Thayer's Gull. Lake County, IL. 23 November 2012.

Adult Thayer's Gull. Lake County, IL. 23 November 2012
Both the Thayer's and the LBBGs were still undergoing outer primary and variable secondary molt:
Adult Thayer's. Lake County, IL. 23 November 2012.
Adult type LBBG. Lake County, Il. 23 November 2012.
Still waiting on this season's first Iceland and Glaucous Gull!

16 November 2012

Can You Say "Astaxanthin"

Astaxanthin is the carotenoid thought to be responsible for the pink feathers we see in gulls (McGraw, Hardy 2005). I've written on this subject in a previous post, but I'm now wondering if this same carotenoid is responsible for the extra yellow/orange we see in bare parts.

Adult Ring-billed Gull. 25 March 2012. Chicago, IL.
Note the pink blemish on the face, neck and breast.
Not only does this individual display pink in its plumage, but the bare parts are on hyper-orange!

Compare it to these ordinary March RBGUs:

It's curious to say the least...

11 November 2012

Indiana Bonaparte's Gulls

Today was a relatively good day for BOGUs on the Indiana lakefront. I observed scattered flocks in Michigan City and at Miller Beach, but the real reward came in Whiting at the BP refinery where I found 71 individuals feeding at the discharge.

Adult BOGU. Michigan City, IN. 11 November 2012.
First Cycle BOGU. Michigan City, IN. 11 November 2012.
First Cycle BOGU. Whiting, IN. 11 November 2012.
Adult BOGU. Whiting, IN. 11 November 2012.
2nd Cycle BOGU. Note the faint black marks on the subterminal part of the tail.
Same individual as above. The black tips to the greater primary coverts and black
markings on the outer web of P9 point away from an adult.
Sadly, Bonaparte's declined greatly on lower Lake Michigan after the 1990s. Of the four states surrounding Lake Michigan (Wisconsin, Illinois, Indiana and Michigan) it seems Illinois sees the least of this species.

28 October 2012

Primary Molt in an Adult Ring-billed

Adult Ring-billed Gulls typically complete their prebasic molts by the end of October. Here's a series of photos documenting primary growth of a known-age RBGU taken at Rainbow Beach in Chicago, Illinois. The photos are presented in three week intervals from late August through late October.This male was banded in the breeding season of 2007 at the Lake Calumet colony.

Just two white primary tips clearly showing past the tertials on 25 August 2012.
Three primary tips showing past the tertials on 15 September 2012. P8 grew significantly in the last three weeks.
Now 4 primary tips showing beyond the tertials on 06 October 2012.
Finally, the tip to P10 (black) has emerged from underneath P9. 26 October 2012. This generally concludes the prebasic molt as most of the body and flight feathers are renewed by the time P10 is fully grown.
The primaries, secondaries and rectrices are all new, crisp, feathers that will get this bird through the winter, spring and most of the next breeding season.

One thing worth noting here is that the mirrors on P10, and particularly P9, are relatively small. This may be an indication as to what an adult this young (6th cycle) should look like, but it's not uncommon for some adults to be without a mirror on P9 entirely. Are these young adult females? Also, might the choppy black markings up the inner web of P8 become "cleaner" as this bird ages? The black marks on the outermost greater primary coverts above P10 are not a sign of "subadultness" - this is an expected feature on adult Ring-billeds.

Rainbow Beach. Chicago, IL. 26 Oct 2012.
To read more about why this bird was tagged, click here.

27 October 2012

California Gull in New Buffalo Michigan

American Herring Gull numbers are beginning to build significantly at various hotspots along lower Lake Michigan. This only means one thing: among them will be some goodies!

I went out to Berrien County Michigan today to observe the relatively large number of Lesser Black-backeds, of which there were plenty, but much more surprising was this California Gull:
California Gull (1st cycle). New Buffalo, MI. 27 October 2012.
The mostly pink bill with black tip grabbed my attention right away. First cycle American Herrings don't typically loose that much black to the bill this early in the fall, and when they do, it appears as a blend of black and pink and is not as sharply demarcated as in CAGU. Also, the post-juvenile molt of the scapulars is rather advanced for the 1st cycle Herrings we're seeing on southern Lake Michigan right now. The gray coloration also stands out and is a bit dark for a Herring.

Overall, this bird appeared messier than the surrounding first cycle smithsonianus birds that were present, but I should mention that 1st cycle CAGUs on the West Coast currently appear much messier than this individual and don't have such "nice" looking post-juvenile scaps right now. Alvaro Jaramillo explained to me that this bird's upperwing coverts are exceptionally neat and appear very "Herring-like". The uniform gray on the scaps is also much "neater" than what is being seen on October CAGUs along the Pacific.

Note the "double" wing bar formed by the darker bases to the greater coverts. It's not uncommon for CAGUs to have a few inner primaries with pale inner webs which resembles Herring.

As for Lessers, I found at least 5 (3 first cycles, 2 adults) but probably could have pulled out another sub-adult if I had the time to comb through the incoming flocks. These birds use the beach as a preen/lube spot before roosting out on the lake for the night.
First cycle LBBG

First cyle Lesser harassaing adult Ring-billed.
Two of the three young Lessers working the surf together.
My estimate of the number of American Herrings at this site is between 600-700 birds. It's not even November yet! WOW!!


 And one last shot of the Cali Gull's wings: