21 December 2014

Michigan City Icelands, Thayer's and Three More Banded Herrings

Gull-watching was rather productive at Michigan City on Saturday. There wasn't much on the beach when I arrived, but gulls soon started trickling in and continued to build up until I departed.

Highlights included 4 Thayer's (3 adults, 2nd cycle), 2 Icelands (both 1st cycles, one intermediate), and 3 banded American Herrings (two 2nd cycles, one adult type).

Kumlien's Iceland Gull (1st cycle). Michigan City, IN. 20 Dec 2014.

Both Kumlien's Iceland Gulls (1st cycles). The individual on the right is somewhat intermediate and shows some dark-wing influence. Whether this qualifies as a Iceland x Thayer's is anyone's guess. Birds like this are not unusual in Newfoundland. See plate 35A.12, but also see plates H5.3, H5.4 and H5.5 in the hybrid section of Howell & Dunn.

Thayer's Gull (2nd cycle). My favorite individual of the day. This bird was a big treat as it snuck up on me and posed for a few minutes. I don't often see 2nd cycle THGUs, let alone one with a paling iris, completed bi-colored bill and with paler tertials like this. 

Note the small mirror on the inner web of p10 - a rather uncommon feature showed on a very small percentage of 2nd cycle smithsonianus.
First cycle Kumlien's (left) with adult type Thayer's Gull (right).
Adult type Thayer's (front) with Herring turned away.
Thayer's with brownish outer web to p10 and brown streaking on greater primary coverts. Near-adult?

Now for the banded Herrings. I was a bit overtaken by all three of these birds, all appearing at more or less the same time. I was successful in recording both band numbers on the 2nd cycles, but the adult had a semi-rotted band that was upside down - impossible!

Band # 1106-26938. Banded in June 2013. Door Co, Wisonsin.

Band # 1106-27230. Banded in June 2013. Door Co, Wisconsin. 

Suffix only: **** -- 91621.
The last 15 or so banded Herrings that I've found between Michigan City, Indiana and New Buffalo, Michigan have all originated from the Sister Bay Islands. I'm beginning to think that the Herrings that arrive on southern Lake Michigan in the Fall/Winter are birds that might not be long-distance migrants. Admittedly though, more data from banded birds in mid-late winter is still needed. The other question to ponder is what happens to the southern Lake Michigan breeders? Do those birds remain here or move to the interior (all the way down through to the Gulf Coast)?

14 December 2014

Black-backeds & White-wingers

I smelled trouble stirring early last week when I read the weekend forecast calling for upper 40-degree temperatures in the Chicago area. Both Saturday and Sunday made it above 50F, with a high of 54 degrees recorded on southern Lake Michigan today (14 Dec 2014). To top it off, overcast skies dominated all of Saturday and most of the day Sunday.

Despite a notable absence of gulls at some of our better gull-watching sites, I still managed to see all five of our winter species with a bit of effort!

Saturday: 13 Dec 2014; Rainbow Beach, Chicago, IL.

GBBG (adult type).
GBBG (adult type).
LBBG (2nd cycle type).
LBBG (2nd cycle).
LBBG (2nd cycle) with Ring-billed (adult) and Herring (1st cycle).
Sunday: 14 Dec 2014; Whiting, IN.

GLGU (2nd cycle).
GLGU (2nd cycle) with adult type Herring.
GLGU (2nd cycle).
GLGU (2nd cycle).
GLGU (2nd cycle) with HERGs.
A heavy-billed, dusky-eyed 3rd/4th cycle type Thayer's Gull.
THGU (3rd/4th cycle type).
Thayer's (3rd/4th cycle type) on far left, with 3 Herrings on right.
THGU (3rd/4th cycle type) with similar-aged HERG (right) and adult type HERG (left).
A shot of both the sub-adult Thayer's and the Glaucous in one frame...not the best photo, but it captures the day's highlights for me:

Here's a nice hatch year Ring-billed to conclude this post. Note how well it's holding on to its juvenile flank, chest and neck feathers. Most similar-aged RBGU's have for some time now shown mostly whitish feathers here, with variable streaking on the head and hindneck that's not as extensive as this:

 RBGU (1st cycle).

RBGU (1st cycle).

11 December 2014

Glaucous & Iceland Day

It's not often that I hit my exact target(s) for the day, but I left my house in the morning saying to myself "I need Glacuous and an Iceland today". The day was a success!

Glaucous Gull (1st cycle). Lake County, IL. 04 Dec 2014.
Notice how the lowered tertials and empty crop (pre-feeding) make this bird look sleeker and somewhat thin. It wasn't a very big GLGU to begin with - not much larger than many of the male type Herrings.
Glaucous is always a long shot at the Fairgrounds and this is only my 5th one for that site.

Adult Icelands are always a treat too, especially when their identity is not clouded by darker, thayeri-like primaries :

Kumlien's Iceland Gull (adult) with similar-aged Herring. Lake County, IL. 04 Dec 2014.
It may take some squinting and stepping back from your monitor, but the tonal values to the upperparts of the Iceland do strike me as being lower than the Herring's. The wingtips of this bird somewhat resemble the Hammond Indiana Kumlien's.

All in all though, the Lake County Fairgrounds had substantially lower numbers this first weekend of December, in comparison to the great end to November. This goes against my prediction of gulls packing the arena after Turkey Day...maybe they were present but glued to the landfill. Temperatures were about 15 degrees warmer and in my experience, this almost never helps the cause.

04 December 2014

Banded Juvenile California Gull

A very exciting part of gull-watching for me is finding banded individuals and retreiving their histories from the Bird Banding Lab. I've reported quite a few birds in the last two years, and have had so many conversations on the phone with the lab, that some of the employees there have come to personally know me as the "gull guy". What a legacy.

Anyway, here's another one to add to the collection:

California Gull (juvenile). Half Moon Bay, California. 12 September 2014.
I entered this bird into the system the same day of the sighting, but just heard back from the lab yesterday:

It's not unusual for the database to be missing data on juveniles, particularly because of banders who haven't submitted their logs (it's a lot of data). The other reason one might get a delayed response from the lab is if the band is very old and predates some of the electronic records (rarely a problem).

In any case, back to the juvenile California Gull. It originates from Mono Lake - one of the biggest California Gull colonies in the United States. Notice the bird has retained a mostly black bill in mid-September, and there are no post-juvenile scapulars grown in yet:

Mostly black bill and juvenile scapulars (slightly late hatch?).
Also note the cinnamon tones to the breast, neck and loral region.
Compare the juvenile above to this hatch year CAGU:

Mostly all of the juvenile scapulars have been replaced and the bill has taken on the classic "bi-colored" pattern that 1st cycle California Gulls are readily identified by. In addition, a few lesser upperwing coverts as well as a single, inner, greater covert have been replaced (the latter perhaps adventitiously).  
Is it likely this individual fledged well before the subject bird? Surely it must have taken some time to acquire all of these post-juvenile scaps (PF/PA1?). A similar thing occurs with our early Fall Ring-billeds here on Lake Michigan. A cohort of hatch year RBGUs on the same beach can have scapulars that range from entirely juvenile to almost all adult-like gray. I've for some time now believed they have to have different hatch/fledge dates.

Off to the next one.

02 December 2014

Cook-Inlet or Thayer's Gull?

I found this first cycle gull in Lake County, Illinois on Friday (28 Nov 2014):

Cook-Inlet (Herring x Glaucous-winged) or Thayer's?
My initial identification was "heavy set" Thayer's, partly because that's what "dark" white-winged gulls default to here, but the more I looked at it, the more I began to wonder. Adam Sell was present at the time, and after pointing the bird out to him, I commented on the semi-muddied look to the scapulars and how they seemed odd.

Jizz-wise, this bird stacked up equally to most of the Herrings around it. Not your run-of-the-mill juvenile Thayer's, although the bill size and structure seemed fine for THGU.
Martin Reid questioned the darker bases to the upperwing coverts and the seemingly short primary projection. This was the motivation I needed to think a bit more about the reservations I had in the field.

Broad arm, dark uppertail coverts and solid, dark tailband seem untraditional for Thayer's.

Barrel body, broad wings and larger head are very reminiscent of Glaucous-winged.
Another thing that bothered me during my observation was what sometimes seemed like an oddly high-placed eye.

It's amazing how a slight change in posture can give a longer look to the primary projection, but the eye-to-face look now appears like a classic Glaucous-winged hybrid.
Notice in the photo above (slightly overexposed) that the bill base looks like it's paling, and it actually was - another strike against a November, 1st cycle Thayer's.

Dark uppertail coverts with wide, solid, distal band. The proximal scapulars look solid brown and not the neatly patterned look I'm used to seeing on 1st cycle Thayer's. This, along with the dark-based upperwing coverts, and darker outer webs to the inner primaries all look like they've been influenced by Herring.
So the final verdict on this one is Cook-Inlet Gull...not the first one I've seen in Illinois and probably not the last!

30 November 2014

Second Cycle Kumlien's Gull

Here in the Western Great Lakes region, many Kumlien's & Thayer's could be suspected of being one or the other. You see, the two have a suite of characteristics that can - and do - overlap in every possible respect. Of course this is not to say that there aren't any clear-cut Kumlien's or clear-cut Thayer's here. There are.

But we also have many birds that take on a "range bias" when they're looked at by outsiders. Thus, the majority of gull enthusiasts on Lake Superior and Lake Michigan are left having to make arbitrary identifications with some of these birds. Fortunately, 2nd cycles are not as difficult as 1st cycles and adults.

Consider this 2nd cycle:
Dark Kumlien's or pale Thayer's? Lake County, IL. 28 November 2014.
I circulated the photos of this bird to several trusted gull aficionados from both regions of the continent (West and East coasts), and as expected, some birders from Colorado and areas to the west, identified it as a pale Thayer's, while birders from New York and east called it a Kumlien's. I favor the latter identification.

Rather plain outer primaries and overall pallid upperparts seem fine for Kumlien's Gull. 
One of the comments made by a birder from the western United States was that the tertials show solid pigmentation throughout and that this ought to support a Thayer's ID. I think that's generally true, but the caveat is that the tertials need to be considered in conjunction with the primaries and upperwing coverts. That is, the tertials on Thayer's tend to be a bit paler than the primaries, which are ideally a darker brown than is seen on this bird. Here's my idea of a "no gimmick" 2nd cycle Thayer's:

Thayer's Gull (2nd cycle). Santa Cruz, California. 17 January 2014.
Thayer's Gull (2nd cycle). Lake County, Illinois. 31 January 2014.
Notice how the tertials act as a color-bridge between the noticeably darker primaries and somewhat paler upperwing coverts.

It would be nice if all of our 2nd cycle Kumlien's were as obvious as the bird pictured below:

Kumlien's Gull (2nd cycle). Lake County, Illinois. 31 January 2014.
Or even this one:
Kumlien's Gull (2nd cycle). Niagara River. New York. 29 December 2012.
But some do have dark, solid-colored, tertials. Here are a couple from the Eastern Great Lakes that would never be second guessed as Kumlien's:

Kumlien's Gull (2nd cycle). Toronto, Ontario. 27 December 2012. Overall solid dark tertails centers, but with lots of internal markings and stippled upperwing coverts. The primaries are not as dark as I'd like to see on a textbook Thayer's. 
Kumlien's Gull (2nd cycle). Toronto, Ontario. 27 December 2012. Very similar to the subject bird. The lack of contrast between the solid tertial centers and pale primaries is standard Kumlien's.
Same bird pictured above. The outer primaries don't contrast much with the rest of the upperparts.
Consider the difference when a classic, 2nd cycle Thayer's opens its wing:

Thayer's Gull (2nd cycle). Michigan City, Indiana. 27 November 2014. The outer 5-6 primaries are markedly darker than the rest of the flight feathers and upperwing.
Thayer's Gull (2nd cycle with adult Lesser). Michigan City, Indiana. 28 November 2014. Although the tertials show pale outer halves, the bases have a solid brown color that's complemented by considerably dark brown primaries.
The take-away from this post should be that 2nd cycle Kumlien's with solid tertial centers are not uncommon, and the key is not to look at this field mark in isolation (as is the case with any field mark). Always compare the tertials to the color intensity of the primaries, along with the overall color of the upperparts.