08 June 2013

Sheboygan Little Gulls

Let's face it, Little Gulls are tough to come across in North America. The species is most commonly seen on the eastern Great Lakes (Erie and Ontario) and on the Niagara River during migration. It's almost always found associating with Bonaparte's Gulls, big or small flocks - no different. The North American Population is estimated at about 400 individuals. Talk about rare!

The first documented nesting attempt of LIGU in North America was in Oshawa, Ontario ("Second Marsh") in 1962. Nesting attempts were evidently unsuccessful, but the species still stages here until this day in the largest numbers known in NA. It is not uncommon to have over 30 adults in alternate plumage carrying out their courtship flights over the marsh here in late April. Tyler Hoar, who has been keeping close tabs on LIGUs in North America for over a decade, has on multiple occasions recorded 100+ individuals at the marsh.

The first successful nesting record of Little Gull in the United States was in Manitowoc County, Wisconsin in 1975 (Wisconsin Birdlife:  Populations and Distribution, Past and Present, 1991, by Sam Robbins). Incidentally, Manitowoc and Sheboygan County Wisconsin remain among the best locations to see this species on Lake Michigan, but by no means is it an easy find.

This year seems to be a relatively exceptional year with at least 5 first cycle birds seen together at Sheboygan's North Point Park. Historically, it was not uncommon to encounter a dozen Little Gulls at locations such as Manitowoc and Sheboygan Wisconsin (between the late 1970s through the late 1990s). The decline of this species on the Wisconsin lakefront seems to be directly related to the decrease in Bonaparte's, but even more importantly, the higher water levels at the aforementioned sites make any prospect of nesting here again unlikely. At least in North America, Littles seems to rarely spend more than a few years nesting at any given site before moving on.

I was able to get up to Sheboygan for a second time this summer to get in on some of the action:

1st cycle LIGU. Sheboygan, WI. 31 May 2013.

Same individual as above.

After closer review of my photos, I was able to confirm at least 4 first summer birds, with a very likely fifth individual. The simplest way for me to tell them apart was by looking at their open tail patterns, along with the condition of their primary tips:

Bird #1
Tailband either faded or most rectrices replaced (the former being more likely).

Bird #2
Full tailband, but all primaries still present.
Bird #3 
Full tailband like the individual above, but note the molt gap between the primaries and the secondaries.
Bird #4
Has replaced 2 inner tail feathers.
Birds #2 and #3 have a very similar tail pattern but the head markings and the carpal bars on the right wing are clearly different. Also, Bird #3 has a few black spots on the lower back. Most interesting about Bird #3 is that it has dropped one, or maybe two, inner primaries. Thus, this individual has begun the second prebasic molt.

Besides the overall diminutive body size, small bill, more prominent cap, thicker and darker carpal bars, I'd like to point out a very simple ID mark that seems to quickly jump out on "most" first cycle Little Gulls: the split black/white pattern on the upperside of the primaries when the bird is at rest. This is seen nicely on the LIGU sitting in the water below:

Little Gulls (left and in flight). Similar aged Bonaparte's (far right). Notice the obvious black and white pattern to the primaries on the sitting LIGU.