29 May 2017

First Basic Outer Tail Feathers on Bonaparte's Gulls

A quick note on 1st cycle Bonaparte's and their tail bands. Specifically, what is the pattern on the outer rectrix (R6)? Does the blackish band extend onto the outermost feathers? Seems like a simple question.

In their account on "juveniles", Olsen & Larsson describe T6 (=R6) as being white with white tips. But in the "first summer" account, they imply the outer tail feather does have black markings. This is somewhat confusing and should be clarified.

First cycle Bonaparte's Gull. R6 apparently white. The tail band on this individual doesn't extend onto the outermost tail feathers. Cleveland, Ohio. November.

Howell & Dunn, however, note that some pigment is found on the outer tail feathers, but limited to the inner webs.

As described in Gulls of the Americas, this individual shows some black on both outer tail feathers, but the pigment is limited to the inner web. Evanston, Illinois. April.

Looking through tens of 1st cycles in my photo collections, I mostly agree with Howell & Dunn, that on average, when there is black on the outer tail feathers (which is rather common), the black is generally limited to the inner web. But not always. Some individuals clearly show pigment beyond the feather shaft.

First cycle Bonaparte's Gull with pigment on R6. The pigment crosses over the feather shaft and onto the outer web on the left R6. New Buffalo, Michigan. September.

Interestingly, when viewing the ventral side of the tail on those individuals with pigment on R6, it usually appears there's more pigment from below than above. This, I suspect, is mainly because the inner webs of the outermost tail feathers are more visible when viewed from underneath. From above, the outer webs are more exposed.

Left R6 shows a substantial amount of pigment. Manitowoc, Wisconsin. May.
Although the pigment spills onto the outer web of R6, it doesn't reach the outermost edge of the feather. Chicago, Illinois. November.

As I've found with 1st basic Franklin's, Black-legged Kittiwakes, Little and Laughing Gull, the pigment on the outermost tail feather appears to be more variable than generally thought. I suspect the same might hold for other species such as Sabine's and Black-headed Gull.

27 May 2017

Wisconsin May Run

Late spring through early summer often brings good gull diversity on the Wisconsin, Lake Michigan lakefront. Here, I can often find a few straggling northern species along with hooded migrants. Last Sunday was a great demonstration of this phenomenon with 10 species between Port Washington, Sheboygan and Manitowoc. Couple this with hundreds of sub-adult Herrings in high molt and the hours spent here are well worth any gull-watcher's time and effort.

The highlight for me was this hyper-melanistic 1st cycle Bonaparte's. I've seen 5 or 6 of these now, with this bird being the most cooperative. Although they're reported annually, these types are rare enough to make one do a double-take.

Possibly a 1st alternate Franklin's where all primaries are renewed
in the first plumage cycle (via PA1).

First cycle Lesser Black-backed (1st summer).

Second cycle Lesser Black-backed Gull (1st summer).
Inner-primary molt signals PB2 has commenced.

Second cycle Great Black-backed Gull (1st summer).

Putative 2nd cycle Glaucous x Herring (1st summer). Photo 1 of 2.

Putative Glaucous x Herring. Photo 2 of 2.

Second cycle Thayer's Iceland Gull (1st summer). Photo 1 of 2.

2nd cycle Thayer's Gull with what appears to be a similar-aged Herring Gull.
Of interest is what appear to be adult-like tips to the 2nd generation (?) primaries coming
in on the Herring. Whether or not the Herring is a 1st summer bird is uncertain. Nonetheless,
I do have suspicions that 2nd basic primaries on some of our Herrings can appear adult-like.

1st summer Kumlien's Iceland Gull. Primary molt has likely begun
but no open wing was observed.

This 1st summer Glaucous Gull tried to go unnoticed but it's difficult to that when you tower over
everything around you. First summer Lesser Black-backed in the background

06 May 2017

Monthly Notables April 2017

  • Ivory Gull (adult). Nome County, Alaska. 01 April 2017.
  • Great Black-backed Gull (1st cycle). Larimer County, Colorado. 01 April 2017.
    • Continued from March 2017.
  • Black-headed Gull (1st cycle). Glynn County, Georgia. 04 April 2017.
  • Laughing Gull (1st cycle). Monterey County, California. 05 April 2017.
  • Sabine's Gull (adult type). Yolo County, California. 07 April 2017.
  • Slaty-backed Gull (adult). Clatsop County, Oregon. 08 April 2017.
  • Lesser Black-backed Gull (adult). Monterey County, California. 11 April 2017.
    • 4th County record. 
  • Laughing Gull (adult type). Lincoln County, Oregon. 11 April 2017.
    • 4th State Record.
  • Franklin's Gull (adult). Kings County, Nova Scotia. 14 April 2017.
  • Slaty-backed Gull (3rd cycle type). Muskegon County, Michigan. 19 April 2017.
    • Michigan's 3rd April record of Slaty-backed Gull. A photo from the Thunder Bay CBC in early January (2017) suggests this may be the same individual, found some 400 miles to the southeast.
  • Lesser Black-backed Gull (adult type). Socorro County, New Mexico. 29 April 2017.

  1. Worthy of mention is what appears to have been a "surge" in Lesser Black-backed Gull sightings on the Central California coast this past season. Interestingly, this was also the case for Oregon where there were 3 coastal sightings (previous to this the state only had one coastal record).