28 May 2014

Banded Great Black-backed Gull on the Indiana Lakefront

I found a banded 1st summer Great Black-backed Gull on the Indiana lakefront yesterday in Whiting:

GBBG (2nd plumage cycle). Whiting, Indiana. 27 May 2014.

Black 3U4.
There can be no doubt about this read as the plastic leg band is easily seen. Here's its life history:
Hatched and banded on Appledore Island, Maine (banded in July 2013). A resighting in September 2013 was reported from Rochester, New York (Lake Ontario).

(Note: the red segments don't imply migration route)

About 1,000 miles from where it hatched, this 1st summer bird will likely remain on southern Lake Michigan for the rest of the season. It will be interesting to see if it returns in subsequent years. Very intriguing is that the Hamilton Lake Watch near Rochester reports that Great Black-backeds are almost always seen migrating "westbound" in late Fall. Perhaps the increasing Lake Michigan winter population is one that exhibits an east-west migration, and doesn't originate from as far north as thought by some.

Well into its 2nd prebasic molt (p1-p4 renewed, p5-p6 dropped, inner secondaries dropped).
Great Black-backeds begin their PB molts relatively early in the spring, faster than most other large white-headed gulls, and this bird is quickly replacing its inner primaries.

I must say, I'm very impressed by the banding efforts of Dr. Julie Ellis and her colleagues on Appledore Island. Many of their Herrings and Great Black-backeds have been reported all throughout the eastern United States, and even as far south as Flordia and the Texas Gulf Coast. Recall that Appledore Island was made famous when an adult Lesser Black-backed Gull (Green F05) was found there for several years hybridizing with an American Herring Gull. The data from Appledore has revealed valuable information about age distributions, migration limits, site fidelity and molt progression in these North American species. To read more on the Gulls of Appledore, click here.

It's no mystery that these large color bands seem to be the reason for so many resightings by ordinary field observers. The color bands are gaining popularity with multiple banders throughout the Great Lakes region and as far as St. John's in Newfoundland. Most impressive is Canadian banders now using these colored rings on Thayer's and Glaucous Gulls near the Arctic Circle, such as the adult Thayer's that Steve Hampton spotted back in January of 2014. I met up with Steve at a landfill in Yolo County, California where he promised me my lifer "California" LBBG. After easily checking off the Lesser and picking through some more gulls, Steve unexpectedly states, "I have a banded Thayer's Gull"!

Adult Thayer's Gull with yellow band on right leg. Banded on St. Helena Island in the arctic.
January, 2014. Photo by Steve Hampton.
We were both awe-struck, not because he spotted this band from over 150 yards away, but because it's the first banded Thayer's either of us has seen.

Map showing location sighting of adult THGU (Yolo County, CA), and banding location on St. Helena.
Map by Steve Hampton.
It's my hope that more and more biologists and ornithologists consider using color rings. Much remains to be learned about our North American Gulls, and it must be said that without ringing programs that involve more input and resightings from ordinary observers, the bigger picture will never be known. Using large color rings is win-win for every party involved. If you're interested in using these bands, and would like help in funding their costs, please contact me!

For a photo of Black 3U4 in juvenile plumage see the Gull-Research website:

27 May 2014

Manitowoc Little Gull

May is generally a good month to find Little Gulls along the Lake Michigan shoreline in east-central Wisconsin. Lakefront cities such as Sheboygan, Manitowoc and Two Rivers usually harbor one or two summering individuals. Most of these birds are 1st summer individuals, lingering back with the small flocks of sub-adult, non-breeding, Bonaparte's Gulls. For the last 3 years or so, this species has been rebounding on the WI lakefront.

Here's one that I found on Saturday in Manitowoc:

First summer Little Gull (1st cycle). Manitowoc, Wisconsin; 24 May 2014.
This is by far the fullest hood I've seen on a first cycle Little Gull. A small percentage of 1-year old birds do show adult-like hoods in their first alternate plumage.

A fiesty bird, this one was relatively big and did not take being pushed around by the surrounding Bonaparte's. It was very skilled at fishing, and gulped down 3-4 shad in the few hours that I observed it.

Bonaparte's Gull in hot pursuit of this agile 1st summer Little Gull.
Beside this beauty, I was also able to record 2 Laughing Gulls (adult in Milwaukee and 2nd cycle in Sheboygan), 4 Franklin's Gulls (adult in Milwaukee, adult in Sheboygan, adult type in Manitowoc and adult type in Two Rivers), and 6 Lesser Black-backed Gulls (all first and second summer birds in Sheboygan).

Franklin's Gull (adult type). Manitowoc, WI; 24 May 2014.

15 May 2014

Recondsidering Tertial Replacement in 1st Cycle Ring-billeds

Post-juvenile molt in first cycle Ring-billeds typically commences in early August, beginning with 2nd generation scapulars. This feather replacement is sometimes extensive and appears to take place quickly as the fall season approaches. By fall, many individuals have almost entirely renewed their scapulars:

1st cycle Ring-billed with a considerable amount of juvenile scapulars replaced. A few median and lesser upperwing coverts have also been replaced. Benton Harbor, Michigan. 01 September 2012.
Usually, there's not much upperwing covert replacement until the 2nd calendar year via the first prealternate molt. Many individuals may go until mid-spring with no upperwing coverts replaced at all:

1st cycle Ring-billed. Upperwing coverts in relatively good condition considering the date.
30 April 2014. Tinley Park, Illinois.
But what about tertial replacement? As my post title suggests, perhaps we need to revisit this feather group: Do 1st cycle Ring-billeds replace their tertials in the first plumage cycle? If so, through what molt? Traditionally, the literature has held that 1st cycle Ring-billeds rarely, if ever, replace tertials. About two years ago, I began to suspect differently as I was finding more and more individuals with juvenile primaries that showed one or two, and sometimes all of their tertials renewed.

1st cycle Ring-billed with advanced post-juvenile molt. Note almost 100% 2nd generation scapulars, moderate upperwing covert replacement, and most interesting, a couple of new tertials (with black centers).
Chicago, Illinois. 27 September 2012.

Now here's an August bird showing one replaced lower tertial.

1st cycle Ring-billed. Extensive scapular molt with moderate upperwing covert replacement. Note the new tertial tucked in the lowest row. Chicago, Illinois. 25 August 2012.
Admittedly, I've never found a 1st calendar year (HY) Ring-billed with all tertials renewed, suggesting that perhaps the individuals I had found were anomalies. And so I paid particular attention to this feather group this spring and have found at least a dozen first cycles with all of their tertials renewed:

Note the white fringes on the newer tertials and upperwing coverts. Does this suggest these feathers were very recently replaced? Tinley Park, Illinois.  06 May 2014.
1st cycle Ring-billed. Same individual above. Note 1st basic (juvenile) primaries with renewed tertials.
Tinley Park, Illinois. 06 May 2014.
 A few more examples:

Tinley Park, Illinois. 06 May 2014.
Tinley Park, Illinois. 06 May 2014.
Tinley Park, Illinois. 15 May 2014.
Tinley Park, Illinois. 15 May 2014.
The evidence I've presented suggests that some individuals, and perhaps many more than we're aware of, do indeed molt their tertials - entirely! But through what molt? This is where it gets tricky...

I was wondering if this can be the result of an early 2nd prebasic molt. Peter Pyle weighed in on this question and suggested it would have to be via the first plumage cycle (i.e., PA1 or PF?):

"The May birds have replaced the tertials during the inserted first-cycle
molt(s). Although tertials are among the earliest feathers replaced during
prebasic molts, at earliest the single middle tertial should have been
growing or replaced by the time p1 drops. That 3-4 replaced tertials are
fully grown before p1 has dropped (in at least the one bird with open
wings) indicates that they had been replaced previously during the winter.

In gulls and shorebirds, the extent of inserted first-cycle molts
correlates well with how far south an individual bird goes for winter, and
a possibility is that these May birds had wintered near the southern end
of the winter range in Mexico or the Caribbean, farther south than occurs
in most other North American gulls. Most birds wintering in the U.S.
appear not to replace tertials. This might explain why first-cycle tertial
replacement had not been detected before or documented in the literature.
Good discovery!"

As Pyle suggests, these tertials are likely first alternate feathers, but what seems perplexing to me is that tertials are technically flight feathers (the innermost secondaries), and for flight feathers to be among the last feathers replaced in a prealternate molt, seems unconventional to me - at least with the large white-headed gulls. I do wonder if they're 2nd basic feathers, making them the first feathers replaced in the 2nd prebasic molt, almost matching the timing of P1 being dropped.

Consider this individual that I found today, 15 May 2014:

It indeed has begun the 2nd prebasic molt, identified by the loss of the innermost primaries:

1st cycle Ring-billed with entirely renewed tertials. Note P1-P2 have dropped, an indication that PB2 has begun.
Tinley Park, Illinois.
What adds to the confusion is not knowing exactly which molt produced the renewed scapulars and/or upperwing coverts. Are these feathers replaced via a prealternate or preformative molt? If prealternate, then it appears this plumage molts in two parts: beginning in late summer with the scapulars (see the first 2 images in this post), suspended for most of the winter, and then resuming in spring with the upperwing coverts (and presumbably the tertials with some birds - see the last 6 images). Of course other body feathers, being less obvious to pinpoint, are replaced during this time as well.

Peter and I are currently discussing the possibility of there being two inserted molts in the first cycle. This to me makes much more sense, paralleling what we see with Bonaparte's Gull, for instance, which exhibits the Complex Alternate Strategy. It may just be that the 2nd generation scaps we see in late summer birds (HY) are preformative feathers, while the new, fresh, upperwing coverts (and tertials in some individuals) acquired in early spring (SY) are first alternate.

Those individuals that show moderate upperwing covert replacement in late summer through early fall (see photos 3 & 4), might be said to undergo extensive PF molts. Those with no upperwing coverts replaced, and less scapular renewal may have limited PF molts. This remains to be seen.

For now more research will be needed to verify 2 inserted molts in the first cycle, and whether or not tertial replacement is via a late PA1 molt, or an early PB2 molt. I feel that we're closer to better understanding molt in first cycle Ring-billed Gulls. Banded birds, museum specimens and more field hours should eventually clarify these questions. This ultimately comes down to knowing how many times a feather tract has molted in a plumage cycle!

08 May 2014

2nd Cycle Type Ring-billed Paired with Adult Female

Here's a photo set of a 2nd cycle type, male, Ring-billed copulating with an adult type female:

Note the white apicals on the female (left). The larger male (right) shows no white tips to the primaries.
Every spring for the last few years, I've been giving much thought to how we define an adult gull. Consider homo sapiens: an adult in the United States is an individual 18 years or older, although this is not the case world-wide. With birds, where nature has a completely different set of rules, is it best to define an adult by a plumage aspect, or biologically speaking, is it to be defined as a bird paired up and carrying out nesting responsibilities? From a field observer's perspective, it's only practical to age a bird by its plumage, but I digress...the simplest scenario is ageing a bird banded as pullus...or is this circular logic?

Here's the wingtip pattern to this apparent adult female that had settled for a "sub-adult" gull:

A thoughtful response I received from Maarten Van Kleinwee regarding this phenomenon of apparent sub-adults breeding:

"It is not exceptional of course for sub-adults (or perhaps better: those with sub-adult plumage) to take part in the breeding process. Last week I saw an adult male Black-headed Gull attempting to mate with a 2nd-calendar year Black-headed Gull. I have also seen 2nd-calendar year Black-headed Gulls on nests and with chicks. Examples exist also of sub-adult large gulls seen incubating".

01 May 2014

Bill Color in 1st Cycle Ring-billeds

Although bill coloration in 1st cycle Ring-billeds is generally described as being pink with a black tip, this pink soon becomes a shorbert orange and a yellowish-green in SY birds. The effect is quite noticable in their first spring:

1st Cycle Ring-billeds all photographed on 21 April 2014. Hammond, Indiana.

Bird #1 is what HY birds typically look like, and bird #4 looks more like a second cycle's bill.

It makes perfect sense that bill color would begin transitioning to a yellow at this time of the year, when hormonal levels peak.