02 February 2016

Appledore Gulls - Herring x Lesser Black-backed Hybrids

Appledore Gull is the title I've suggested for putative American Herring x Lesser Black-backed hybrids. They appear to be increasing with rapidity and it seems every week I'm being sent photos or someone is posting good candidates of this combination.

There are two individuals that have provided us with some insight: "Green F07" and "Green F02", the offpring of an American Herring and Lesser Black-backed Gull (Green F05) from Appledore Island in Maine.

Green F07
This is the most well-documented hybrid available to us in North America. Interestingly, this bird has kept mostly yellow legs in 4th basic. It's easy, then, to discredit the notion that adult F1 hybrids should have a blend of dull pink and yellow legs.

Green F02
This bird has been missing in action since 2nd basic. It looks much more like a 2nd cycle Lesser than a Herring (or an intermediate bird for that matter). Both size and the gray upperparts don't scream Herring Gull to my eyes.


Green F05. Banded on Appledore Island after found hybridizing with American Herring Gull.
This individual, known as Pierre, has been documented up and down the Atlantic, spending most of
its winters in the Daytona Beach Shores area. More here.


While in Florida a couple of weeks ago, I found two examples of adults that I feel make good candidates of this hybrid combination. Let's start with the more obvious individual.

BIRD #1











BIRD #2







I base my identifications of these two birds primarily on two points: intermediate upperparts and corrupted leg color. P-molt is better for a LBBG at this time of year. The head/bill on both birds look more like Herring Gull, to me.  

The continuing barrier of little data and few known-age, known-provenance birds makes our identifications tentative. There is no known "hybrid zone" where we can openly observe this mix, and so the range of features in these hybrids is reduced to guesswork and imagination. This presents several critical identification problems for North American observers: 1) Identifying Yellow-legged Gulls with confidence, 2) Confusion with dark-backed "Herrings" and pale-backed "graellsii".

01 February 2016

Monthly Notables January 2016

  • Ivory Gull (1st cycle). St. Louis County, Minnesota. 01 January 2016.
    • 12th State Record. Took a 6 day absence, only to return to Canal Park on 15 January 2016. It was last seen on 24 January appearing weak and on the brink of expiring.
  • Mew Gull (1st cycle). Caddo County, Louisiana. 01 January 2016.
    • 1st State Record.
  • Ivory Gull (1st cycle). Douglas County, Wisconsin. 05 January 2016.
    • Just a few miles from the Duluth bird, this individual was found dead. A partial specimen was given to the Field Museum in Chicago.
  • Slaty-backed Gull (adult). Pierce County, Washington. 06 January 2016.
    • Reoccurring/Continuing. 
  • Slaty-backed Gull (adult type). Jefferson County, Wisconsin. 07 January 2016.
  • Slaty-backed Gull (3rd cycle type). Walla Walla County, Washington. 08 January 2016.
    • First for eastern Washington.
  • Kelp Gull (adult). Summit County, Ohio. 10 January 2016.
    • Resighted after a ten day absence.
  • Thayer's Gull (adult). Horry County, South Carolina. 11 January 2016.
    • 1st State Record. Adult showing a single mirror on p10 and none on p9.
  • Black-tailed Gull (3rd cycle type). Clinton County, Illinois. 11 January 2016.
    • 2nd State Record.
  • Mew Gull (sub-adult/3rd cycle type). Lorain County, Ohio. 12 January 2016.
  • Ivory Gull (1st cycle). St. Louis County, Minnesota. 12 January 2016.
    • Another addition to the Ivory Gull saga in St. Louis County this month. A 1st cycle was found in a backyard in Ely, MN, being mobbed by crows. It was picked up and looked after by rehabbers and then released shortly after. All this while the Canal Park bird was missing in action. No photos were taken of the Ely bird (some 100 miles north of Duluth) and so whether this is a 3rd Ivory Gull or not is unknown. Three days later the Canal Park bird did reappear. 
  • Iceland Gull (1st cycle). San Diego County, California. 18 January 2016.
  • Mew Gull (1st cycle). Knox County, Maine. 18 January 2016.
  • Vega Herring Gull (adult). Cameron County, Texas. 18 January 2016.
    • 6th (7th?) State Record.
  • Slaty-backed Gull (adult). Contra Costa County, California. 19 January 2016.
  • Franklin's Gull (1st cycle). Volusia County, Florida. 19 January 2016.
  • California Gull (1st cycle). Kings County, New York. 19 January 2016
  • Vega Herring Gull (1st cycle). San Mateo County, California. 20 January 2016.
  • Iceland Gull (1st cycle). Brevard County, Florida. 21 January 2016. 
  • Common Gull (adult). Dartmouth, Nova Scotia. 25 January 2016.
  • Slaty-backed Gull (adult). Solano County, California. 25 January 2016.
  • Thayer's Gull (2nd cycle). Northampton County, Pennsylvania. 26 January 2016.
  • Black-headed Gull (adult). Vancouver, British Columbia. 26 January 2016.
  • Slaty-backed Gull (adult). Will County, Illinois. 26-29 January 2016.
    • This same individual was found some 70 miles to the northeast at Montrose Harbor in Chicago on 30 January 2016. It was observed for about an hour before it flew off to the north, not to be seen again. This is now the 20th gull species seen at this site.
  • Thayer's Gull (adult). Cecil County, Maryland. 27 January 2016.
  • Slaty-backed Gull (adult). Milwaukee County, Wisconsin. 30 January 2016.
    • Photo comparisons suggest this is a different adult than the one observed earlier in the month in Johnson Creek, WI and the individual observed in Illinois.
  • Sabine's Gull (1st cycle). St. Vincent's, Newfoundland. 31 January 2016.
    • A rare sighting from land. Exceptionally rare in North America in winter.

January 2016 Quiz

Intermediate Thayer's/Kumlien's Gull. Whiting, Indiana. January 2015.

We begin 2016 with classic, large white-headed gull, muddiness. This adult type white-winger evoked some interesting discussions this month. Here were the answers I received from you guys:

  • 22 Thayer's Gull
  • 14 Kumlien's Iceland Gull
  • 3 Herring Gull
  • 2 Thayer's/Kumlien's Gull
  • 1 Glaucous-winged x Herring
We can rule out Herring Gull - not because of the extensive white on the outer primaries - but by the paleness of the pigment on the outer primaries. Note that some Herring Gulls, particularly in Eastern North America, show reduced black and thayeri wingtips like the individual below. The pigment is a true black:

Florida; January.

Back to our quiz bird. In the field, we'd want to gauge its size by comparing it to other species if possible:

Herring Gulls with Quiz bird (right)

This wasn't a very large gull, averaging smaller than most of the surrounding Herrings. For this reason I've dismissed a Glaucous-winged x Herring Gull hybrid (which can show a similar wingtip). 

It's clear from the photo above that the wingtip is significantly paler than the black shown on the adjacent Herrings. This is outside of my comfort zone for a "pure" Thayer's type. For some people, this would be a perfectly acceptable Kumlien's Iceland Gull, and it very well may be. However, my reason for identifying it as a Thayer's/Kumlien's intermediate type is the extent of black on p5. 


It's currently accepted that the majority of Kumlien's (in core Kumlien's winter range) don't show a complete subterminal band on p5 as is seen here. Further, the amount of pigment bleeding onto the inner webs of p9 and p10 is more reminiscent of what we see in Thayer's Gull. If the wingtip was a shade darker - a more genuine black - I would've readily identified our quiz bird as a Thayer's Gull.

A couple of comments in the answers provided mentioned eye color as a reason why this would be a Kumlien's Gull. It should be known that iris color in both Thayer's and Kumlien's is highly variable - some Kumlien's have dark eyes while some Thayer's have pale eyes. In short, eye color is not a helpful field mark in trying to distinguish these two taxa.

It's not uncommon to find wingtips like this here in the Lake Michigan region and elsewhere in the Great Lakes. These birds are controversial at best, and some gull enthusiasts have recently begun calling them "Lake Michigan Gulls" as they appear to be the center of the divide. Our safest bet is to think of Thayer's/Kumlien's as a continuum rather than trying to pigeon-hole every individual in one box or the other.

28 January 2016

The Smell of Progress - Lesser Black-backed Resight

Last winter, Michael Brothers and Jay Barry from the Marine Science Lab began banding Lesser Black-backed Gulls in Volusia County, Florida. The first bird to be banded was Green F:001. You may recall I photographed this individual in Daytona Beach Shores last January:

Green F:001 in its 1st plumage cycle. Volusia County, FL. 24 January 2015.

While on gull patrol at the Brevard County Landfill last week, I refound our friend, almost one year later to the day - totally unexpected, roughly 70 miles south of where it was banded the previous winter!

Green F:001 in its 2nd plumage cycle. Brevard County, FL. 23 January 2016.
Now in 2nd winter garb, I was most surprised by how adult-like the iris and body feathers appear. Compared to many other similar-looking 2nd cycles, F:001 shows quite a bit of head streaking but with all-white uppertail coverts.




Open-wing shots from 1st to 2nd cycle:


 

My shift on the top of the hill was well-rewarded. This sighting is a strong indicator that there is some winter site-fidelity with the Lessers found in east-central Florida. There's much more work to be done and thanks to Michael and Jay for helping "crack the code" in determining where these birds are coming from, where they reside in the breeding season and where they go in the winter.

You can see more of F:001 in 1st basic here.

Two Kumlien's and An Iceland - Huh?

Last week we found 3 Iceland Gulls down in east-central Florida: 2 kumlieni and 1 nominate glaucoides - all first cycles.



The first Kumlien's was rather classic in structure, but showed a bi-colored bill and a few 2nd generation scaps.

Kumlien's Gull. Volusia County, FL. Photo 1 of 4.

Photo 2 of 4.

Photo 3 of 4
Photo 4 of 4.

Kumlien's #2 was a beefy son-of-a-brute with a short wing projection and disproportionately small bill.

Kumlien's Gull (1st cycle) with Laughing Gulls. Brevard County, FL.  Photo 1 of 3.

Photo 2 of 3.


Photo 3 of 3.
And finally, the star white-winger, this small Iceland Gull that fits nominate glaucoides perfectly:

Iceland Gull (1st cycle). Photo 1 of 5.

Photo 2 of 5.

Photo 3 of 5.

Photo 4 of 5.

Photo 5 of 5.
This last bird showed uniform pale primaries, a very small build, dome-head and petite bill. Interestingly, while looking at my photos on the boat, I began to reject the idea of this being a Kumlien's. A short friendly debate ensued with those folks standing around me.  I walked over to Steve Howell to show off my best photo of this bird, to which he immediately commented, "This would never be called a Kumlien's in Europe". I could not agree more!

27 January 2016

From Maine To Florida - Herring Resights

While on gull patrol at the Brevard County Landfill in east-central Florida last week, I found 2 first cycle Herrings with field-readable bands. Both birds originate from the Gulf of Maine:

Brevard County, FL. 21 January 2016. Green 26H was banded as a chick on Appledore Island in Maine on 15 July 2015.
Photo 1 of 4. 

Photo 2 of 4.

Photo 3 of 4.

Photo 4 of 4.

A couple of days later I found this individual with a red/maroon field-readable - a color I had never encountered:

Brevard County, FL. 21 January 2016. Maroon J3J was banded as a chick in Hancock County, Maine on 01 July 2015. 
Photo 1 of 4. 

Photo 2 of 4.

Photo 3 of 4.

Photo 4 of 4.

I learned yesterday that these Hancock County Herrings are being banded by John Anderson and his team, primarily on Great Duck Island and Mt Desert Rock, roughly 150 miles to the northeast of Appledore Island in the Gulf of Maine.


23 January 2016

Kumlien's The Word

Yesterday, Michael Brothers, Jim Danzenbaker, Steve Howell and I led the Gull Fly-In at Daytona Beach Shores in Volusia County, Florida. Steve suggested we split our large group up according to skill level and off we went. As I was walking south with my squad I spotted - for the second day in a row - a 1st cycle Kumlien's Iceland Gull. This was a more classic-shaped bird, but oddly, it had a rather bi-colored bill. This after me lecturing a few hours earlier at one of my talks about how 1st cycle Kumlien's keep black bills in the winter and Glaucous Gulls have pink bases to their bills. That'll teach me not to use the word "usually" as a disclaimer.




Kumlien's Gull (1st cycle). Volusia County, FL. Only Florida's second KUGU of the season.

Nothing else to speak of other than a few LBBGs & GBBGs:

3rd cycle type GBBG with adult HERGs and adult LAGU.

1st cycle GBBG.

3rd cycle type LBBG with adult HERG.

Adult & 2nd cycle type LBBG with adult HERGs.