31 December 2017

December 2017 Quiz


Age: The upperparts on this bird have neat pale fringes that immediately suggest a juvenile. The jet-black bill and pointy tips to the primaries also support a 1st cycle individual.

Identification: The medium, even-brown, tones with very little contrast throughout the plumage is only expected in a couple of taxa in North America. An initial view of the extensive pale edging wrapped around the primary tips should call to mind juvenile Glaucous-winged Gull or Thayer's Gull. A date and location, or other birds in the frame for comparison, would easily settle this in the field, but we'll try to do without that information. Afterall, what do we have to lose?

A couple of salient features that Glaucous-wingeds regularly show - but not so much in thayeri - include a plain, muddied, greater covert panel. In thayeri, the greater coverts tend to show more internal markings with a frosted appearance - more illustrious, if you will.

The plain upper tail, plain tertial tips, plain scapulars and plain wing coverts nicely work together to shape this "muted" look we expect in Glaucous-winged Gull. Our December quiz bird is indeed a juvenile Glaucous-winged, photographed in King County, Washington during the first week of September.

For comparison, here's a juvenile Thayer's, photographed in the same county in late December:

Greater coverts show more internal markings, and overall, the upperparts are more contrasty and patterned. An ID like this, where Glaucous-wingeds and Thayer's overlap, must also take size and structure into consideration.

30 December 2017

Favorite Trio of 2017

Well, another year is in the books. Almost. I'm not crazy about these "year-end reflection" posts, but what else is one to do at the very end of the calendar year? So here it goes: My top 3 birds for 2017.

Number 3: An early fall trip to the Salton Sea allowed for some much needed reacquainting with this winged Mexican wayfarer. I spent a few days here soaking up some rather interesting molt patterns with an impressive group of lingering birds. Here's the "neatest" adult I could capture.

Adult Yellow-footed Gull. Imperial County, California. 29 September 2017. 



Number 2:  This Asian beast came barreling in for a spectacular appearance while I was working the Herrings on a small inland lake in Pleasant Prairie, Wisconsin. It's only my second self-found Slaty-backed Gull. Of more interest is that both of "my" Slaty-backs are each 1st county records, sitting adjacent to each other across state lines: Kenosha County, Wisconsin and Lake County, Illinois.

Adult Slaty-backed Gull. Kenosha County, Wisconsin. 10 December 2017.



Number 1:  My summer came to a standstill on the last day of August when this Galapagos endemic was spotted in Seattle. I made it out there two days later on a total crap shoot as the bird was moving up and down the sound with no predictable pattern. Fortunately for me and lots of other birders, Shelley Rutkin and Philip Dickinson refound the bird in Everett, Washington on that Saturday - the farthest north it was ever seen during its foray, and now the northernmost occurrence for the species.

Adult Swallow-tailed Gull. Snohomish County, Washington. 02 September 2017.


And there you go. Thanks for reading. Wishing you a prosperous year ahead!

26 December 2017

Racine & Kenosha - Christmas Day

Some Christmas Day gulls from Racine & Kenosha Coutnies in far southeast Wisconsin. The considerable drop in temperature here, and landfills being closed for 3 consecutive days makes for very antsy gulls. A barrage of 27 Icelands was tallied (14 thayeri, 9 kumlieni, 4 thayeri/kumlieni), and my suspicion is that there are at least half this many roaming the area that went unnoticed. I didn't keep a very accurate count of Herrings, but between my 4 stops yesterday, I would put the number at roughly 3,000. No Slaty-backs. No Californias. No Kittiwakes...

Highlights: 
6 LBBG. 4 GLGU. 1 GBBG. Glaucous x Herring (adult), Great Black-backed x Herring (adult), and a putative 1st cycle Lesser Black-backed x Herring (future post). 
Kumlien's Gull (1st cycle). Kenosha County, Wisconsin. 25 Dec 2017. Photo 1 of 2.




Thayer's Gull (1st cycle). Kenosha County, Wisconsin. 25 Dec 2017. Photo 1 of 3.



Lesser Black-backed Gull (1st cycle). Kenosha County, Wisconsin. 25 Dec 2017. Photo 1 of 3.



Kumlien's & Lesser (1st cycles). Kenosha County, Wisconsin. 25 Dec 2017. Photo 1 of 3.

Glaucous Gull (adult). Racine County, Wisconsin. 25 Dec 2017. Photo 1 of 3.



Glaucous & Herring Gull (3rd cycle). Racine County, Wisconsin. 25 Dec 2017. 

Kumlien's Gull (adult). Racine County, Wisconsin. 25 Dec 2017.

Iceland Gull (adult). Racine County, Wisconsin. 25 Dec 2017.

Iceland Gull (adult). Racine County, Wisconsin. 25 Dec 2017.
Kumlien's Gull (adult). Kenosha County, Wisconsin. 25 Dec 2017.

Kumlien's Gull (adult). Racine County, Wisconsin. 25 Dec 2017.

Kumlien's Gull (adult). Racine County, Wisconsin. 25 Dec 2017.

Kumlien's, Thayer's (adult & 1st cycle), Herring (adult). Racine County, Wisconsin. 25 Dec 2017.

Iceland Gull (adult). Kenosha County, Wisconsin. 25 Dec 2017.

Thayer's Gull (adult). Kenosha County, Wisconsin. 25 Dec 2017.

Thayer's Gull (adult). Kenosha County, Wisconsin. 25 Dec 2017. Photo 1 of 2.

Thayer's Gull (adult). Kenosha County, Wisconsin. 25 Dec 2017.

Thayer's Gull (adult). Kenosha County, Wisconsin. 25 Dec 2017. Photo 1 of 2.



Thayer's Gull (adult). Kenosha County, Wisconsin. 25 Dec 2017. Photo 1 of 2.



16 December 2017

Steelworkers Black-legged Kittiwake

On-and-off at Steelworkers Park on the southeast side of Chicago for at least 3 weeks, I finally got out to see "the" juvenile kittiwake today.



Jake Cvetas and I watched it in the water for a bit before it made a couple of passes over our heads and settled on the old wall adjacent to the defunct boat channel. I almost forgot this species is most comfortable resting on elevated rocky structures.


Black-legged Kittiwake (1st cycle). Cook County, Illinois. 16 December 2017.

On to the next one...CBC gulls beckon on the Mississippi River!

Advanced Rectrices in 2nd Cycle Lesser Black-backed Gulls

Four advanced, white, tail feathers on an otherwise typical 2nd cycle Lesser Black-backed.
Kenosha County, Wisconsin. 10 December 2017.

The above bird from last weekend has inspired this post. The mismatch in tail-feather pattern doesn't seem to be too uncommon in this age group. I do wonder if these are 3rd generation feathers contained in the 2nd molt cycle (via an extensive prealternate molt). 

Here are a few more individuals from east-central Florida to chew over.


Bird #1 - Volusia County, Florida. 23 Jan 2015.



Bird #2 - Brevard County, Florida. 26 January 2015.



Bird #3 - Brevard County, Florida. 24 January 2016.


Bird #4 - Brevard County, Florida. 26 January 2017.

Appears to be in active molt. 

11 December 2017

Another Slaty-backed Gull

A day trip to Kenosha County, Wisconsin yesterday was rewarded with this adult Slaty-backed Gull.

Adult Slaty-backed Gull (L. schistisagus). Pleasant Prairie, Wisconsin. 10 December 2017.

I found it at Lake Andrea around 1:00 pm after having spent the last 4.5 hours there, working a growing flock of Herring Gulls. The flock wasn't too shabby to begin with, giving up 11 Iceland

10 December 2017

Variable Widths to Inner Primary Tips in Iceland Gulls

A few years ago I began to notice a small percentage of adult-type Iceland Gulls (thayeri & kumlieni) that have relatively broad white tips to the inner primaries.

The most extreme of these types recalls a pattern not unlike the trailing edge on Slaty-backed Gull:
An unusual pattern with white tips to the inner primaries congruent in width to those of the secondaries. Also note how white eats into the feather shafts on p2-p5. Chicago. January.

I've only seen 3-4 birds similar to the one above. Others generally have slightly more narrow tips to p1-p2, but widen thereafter.

09 December 2017

Detecting Thayeri P9 Patterns

Outer primary patterns in large gulls provide much appeal to the discerning eye. One particular pattern that "pops" is the so-called thayeri pattern found on the 9th primary:

The mirror on p9 merges with a white inner web. © Martin T. Elliott



This pattern is found on multiple taxa - not only Thayer's - but is only visible when the primaries are sufficiently spread. Below is a short series of the same bird demonstrating this:

The inner web to p9 is sufficiently exposed with the primaries spread.

As the wing begins to fold the inner webs are less exposed.

No thayeri pattern is detected here as the inner web to p9 is covered by the outer web of p8. 

With many contemporary papers on large gull ID relying less on "birds in the hand" and museum specimens, it's imperative that fully spread wings are obtained. Digital photography has made capturing these details relatively simple, and it allows a closer look at what would otherwise be fleeting glimpses in the field.