31 October 2016

October 2016 Quiz

Age: The adult-like gray scapulars down the middle of the back and lightly marked uppertail coverts immediately suggest a 2nd cycle type. Also, the solid black tertials with relatively wide white edges support a bird not in its 1st plumage cycle.

Identification: The largely uniform brown wings and dark gray central scapulars point to a dark-backed species. The checkered lesser and median coverts are suggestive of Lesser Black-backed Gull. The lightly barred/marbled region in the tail feathers (specifically the partition between the black tail band and white uppertail coverts) also resembles LBBG, and that's what this month's quiz bird was identified as.

Berrien County, Michigan. September.

Here's a more detailed photo of this rather "large" Lesser:

10 October 2016

Possible 1st Cycle Herring x Lesser Black-backed Gull

I'll begin this post by reiterating - as I always do - that I'd much rather leave confusing young gulls unidentified than assign a hybrid label to them. There is no sense in jumping to conclusions when there are no data to support them.

With that said, here's a bird I first thought may be a 1st cycle Lesser, then decided it was okay for a 1st cycle Herring, and then started scratching my head the longer I looked at it.

Structurally, the rear looks very little like an American Herring and much more like a Lesser. The sparsely marked vent area is also unusual.  
The, longer, solid outer median and lesser coverts also resemble Lesser Black-backed, more than American Herring.
"This is NOT a pure American Herring" were my thoughts after seeing the undertail.
The white vent is not something I've encountered with juvenile American Herrings. But now see the open wing...
The uppertail contrasts greatly with the rest of the body, but most disturbing is the strong contrast to the pale inner primaries (only seen well in brighter lighting).
In this slightly underexposed image, it looks long-winged, shows less of an inner primary window, and the tail almost looks like it was trying to go for a banded look but failed miserably. 
If this is an American Herring Gull or Lesser Black-backed Gull, then I have to admit that I don't yet know these species well. It sure doesn't feel right for either taxon. On the other hand, it does look intermediate in many ways. Another one for the mystery file.

Juvenile Lesser - Little Pretty

I'm up to my 5th juvenile LBBG so far this season. This one really hit the mark with stunning outer tail feathers showing spectacular barring:

New Buffalo, Michigan. 07 October 2016.

The breast often looks more coarsely marked than American Herring.

Head/neck streaking finer and less marked than in American Herring counterparts. The undertail is with a white base and a neater pattern. The vent area has significantly less markings than American Herring.

Comparisons, now, with an American Herring Gull:

09 October 2016

Michigan City & New Buffalo - 07 October 2016

Just a few miscellaneous notes on birds seen on Friday.

Herring with virtually no mirror on p10 (still growing). P4 with small speck on outer web and marked p-coverts/alula suggest a 4th cycle type. Michigan City, IN. 07 October 2016.

Same individual above. A mostly adult-like bird near finishing prebasic molt.
Another adult type with a large p10 mirror showing several white "spots" on the underside of the primary. P-9 with a weak thayeri pattern. Michigan City, IN. 07 October 2016.
Adult type Herrings. Left bird already in nonbreeding condition while the bird on the right has bright legs and bill. The most natural explanation for this is hormonal variance. 
Sub-adult Herring with the often-seen black ink spot on the tertials. Also of interest on this bird is subtle hints of wavy barring on the neck/breast. Although this is most commonly seen on Glaucous-winged Gull, Herrings too can show it.
1st cycle Herring with ~90% of scapulars 2nd generation. Rare is to see a few (inner) upperwing coverts replaced already (likely PA1). Bill is beginning to pale. Also of interest on this bird is a paling forehead, an attribute often found in similar-aged California Gulls.
2nd cycle Herring Gull. A very obvious marbling to the greater coverts and tertials, unlike in 1st cycle birds. The primary tips are rounded (and still growing - see next image).

A still largely marked tailband, with reduced markings on the upper rump. The inner primaries are more silvery than is seen on 1st generation primaries. The axillaries are mostly white as expected at this age.
1st cycle with ~100% of scapulars replaced. Somewhat unusual is a few wing coverts (median and greater) have been renewed. This usually doesn't take place with the majority of hatch year herrings that I encounter. A better angle of this in the photo below..

6th Cycle American Herring Gull

A short visit to New Buffalo on Friday, 07 October 2016, yielded this cooperative adult that allowed a full band read:

#1106-19489. Banded as a flightless chick in Egg Harbor, Wisconsin on 15 June 2011.

The bill is relatively small for Herring, suggesting a female type. 

Although the black w-band on p-5 (right wing) is typical, the white tongue tip is not.
Primaries out to p7 fully grown.

P8 almost fully grown, p9 about 1/3 grown and p10 just coming out beyond the wrist.
Outermost and innermost secondaries growing. Most secondaries still tucked under greater coverts.

There was a 2nd banded HERG too but a hopeless chance of capturing the entire sequence:

Dirty band in need of replacement. The condition of this band doesn't neccessarily imply the bird is old. It could just be this individual has been exposed to lots of "sticky" stuff.

01 October 2016

Monthly Notables September 2016

  • Sabine's Gull (adult type). Charlotte County, New Brunswick 02 September 2016.
    • Continuing adult from late August, molting into basic plumage.
  • Laughing Gull (2nd cycle type). Santa Barbara County, California. 02 September 2016.
    • Continued from August.
  • Little Gull (juvenile). Douglas County, Colorado. 03 September 2016.
    • Stunning bird with 75%+ juvenile scapulars. Photos.
  • Little Gull (juvenile). Polk County, Iowa. 03 September 2016.
  • Black-legged Kittiwake (juvenile). Virginia Beach County, Virginia. 03 September 2016.
  • Sabine's Gull (juvenile). Marathon County, Wisconsin. 07 September 2016.
  • Sabine's Gull (juvenile). Jackson County, Missouri. 07 September 2016.
  • Lesser Black-backed Gull (3rd cycle type). Coconino County, Arizona. 08 September 2016.
  • Little Gull (juvenile). San Mateo County, California. 11 September 2016.
  • Franklin's Gull (1st cycle). La Mitis County, Quebec. 12 September 2016.
  • Lesser Black-backed Gull (adult type). Imperial County, California. 14 September 2016.
  • Western Gull (2nd cycle). Washington County, Colorado. 16 September 2016.
    • Continuing banded bird from Farallon Islands. Now in complete 2nd basic garb.
  • Western Gull (juvenile). Salt Lake County, Utah. 13 September 2016. Photos.
  • Glaucous Gull (2nd cycle type). Essex County, Ontario. 16 September 2016.
  • Slaty-backed Gull (adult). Pierce County, Washington. 20 September 2016.
  • California Gull (adult). Berrien County, Michigan. 21 September 2016.
  • Laughing Gull (adult type). Morgan County, Colorado. 27 September 2016.
  • Thayer's Gull (juvenile). Grand Forks County, North Dakota. 28 September 2016.
    • A tad early. Still growing outer primaries. Photos.
  • California Gull (2nd cycle). New Haven County, Connecticut. 29 September 2016.
    • Possibly "the" 1st cycle bird seen back in April 2016 - a 1st state record then. Photos

Miscellaneous Notes

  • Juvenile Sabine's Gulls made an above-average appearance throughout the western Great Lakes region this month. A handful of adults were recorded as well - not something that occurs annually! 
  • Western Gull is now being reported with more frequency in the interior west. This movement away from the Pacific coast is augmented by the relative increase at the Salton Sea (a high count of 8 this month) and other inland bodies of water. The species is certainly on my radar and I feel it's only a matter of time before one strays to the Great Plains and east to the Mississippi River Valley.

September 2016 Quiz

The September bird appears to be a large 4-year gull. The trickiest part about this month's quiz - in my opinion - is correctly aging our gull. At first glance it looks like a 1st cycle, but a more careful look should reveal a 2nd cycle type. 

It's difficult to be sure what the true primary projection length is because those feathers are raised. But the projection does look suspiciously short, indicating the outer primaries are still growing. The tips are rounded which favors a 2nd cycle type over a 1st cycle. The newer, gray, central scapular feathers do resemble a 1st cycle type as they show dark marks along the shafts and some barring.

But scapular patterns are highly variable in large gulls and they can often betray a bird's true age. The wing coverts, on the other hand, are a bit more reliable when aging. Notice the obvious marbling pattern to the greater coverts and distal tertial edges. This is more typical of a 2nd cycle gull. Also notice in this images the rounded tips to the outermost primaries.

But what species? The bird is not very large or bulky. The relatively small and straight bill call to mind species such as California Gull, Lesser Black-backed Gull and Herring Gull.  

The paling iris and pink legs should immediately dismiss thoughts of a California Gull, and the relatively light gray scapulars raise doubts about this being a Lesser Black-backed Gull. I identified this month's bird as a retarded 2nd cycle type Herring Gull, photographed in Northern Illinois. January.