26 December 2010

1st Cycle Herring Gull

I found this American Herring Gull at Miller Beach in Gary, IN on 22 December, 2010.

My initial impression was perhaps a delayed 2nd cycle bird because of the combination of the gray scapulars, bleached head and neck, and the pale coloration to the bill. The basal part of the bill seemed a bit too pale for a 1st cycle in December. 1st cycle Herrings usually, but not always, retain more black in the bill in the early part of the winter season; some will have the basal 2/3 of the bill completely pale with just a black tip.

The head on this bird is bleached along with parts of the neck and chest - a look that's not really expected in early winter. After a closer look at the upperwing coverts, a pattern that's much more consistent with a younger bird is revealed. 2nd cycle individuals have a finer pattern to the greater coverts or sometimes show signs of abrasion and fading. I waited a few minutes and watched it take wing. It became obvious that the flight feathers were those of a juvenile in its first molt cycle. This individual is probably no more than 6 to 7 months old.

I think it's safe to say that this gull has undergone a moderate to accelerated post-juvenile molt of the scapulars, but there's still several obvious juvenile scapular feathers showing (even in the photograph of the bird standing). The head and neck area have likely whitened by bleaching but there's also the possibility that some head, neck and chest feathers are being replaced by the initiation of the 1st prealternate molt.

Here is a more typical 1st cycle Herring for mid-late December:

Note the almost entirely black bill that is just starting to show pale markings. The scapulars have a few new gray feathers but not predominating, and the head and neck are not bleached as the individual above. Both of these birds were photographed minutes apart at Miller Beach.

Knowing what a particular aged American Herring Gull should look like in any given month of the year is not an easy task. The variation in appearances will always offer the keen observer something worthy of pause. It's important to realize that there's an expected array of "aspects", for instance, with 1st cycles in early winter, mid-winter and late winter. Learning these limits of variation for species like Herring Gull are, in my opinion, foundational for anyone that has a serious interest in North American gulls.

25 November 2010

Twitching the Colorado Ross's Gull

On Friday, 18 November 2010, I got an email from the Kansas listserv with “Extralimital Ross's Gull” as the subject. As I began reading the report my mind started to race, thinking about the arrangements that would have to be made in the next 24 hours. It wasn’t a question of am I going to twitch this one, but rather, how am I going to twitch this one. When I found out the bird was being seen in Colorado outside of the Denver area, I thought it would have to be done by airplane. I soon scratched the airplane idea as the cheapest ticket was $419 for a next day flight. Googlemaps estimated a oneway trip to be roughly 16 hours. Piece of cake.
The bird was found Friday morning by Joe Roller who originally ID'd it as an adult Little Gull but later concurred with a Ross's Gull ID made collaboratively by himself, Glen Walbek and Cole Wild. The ID was confirmed that same afternoon. The photos were released and this, more than anything, drove me over the top. I waited it out and followed the updates for the next 6 hours. I made a post on the Illinois Birders Forum to inform birders of this rarity. Bruce Heimer, who I knew would be the first to call me, called and left me a message the next morning with these being his first words, “Dude, the bird is still being seen”. No clarification was needed for “the bird”. Bruce was one of the 5 birders who joined me for the Cape May Ivory Gull twitch just 11 months prior. On the ride home from Cape May we explicitly said to one another that a Ross’s Gull would warrant similar actions.

On Saturday, 20 November - less than 24 hours after the initial report - we finalized our plans and were able to enlist Greg Neise, Chris West (probably one of the most active and talented ABA birders in his age bracket) and both of the Gyllenhaal brothers – Ethan and Aaron. This was a very bizarre chain of events as Chris, Ethan and Aaron had also been on the Ivory Gull twitch with us. Meeting time was at my house at 8:00 p.m. Bruce was responsible for picking up Greg, Chris was on a 3.5 hour trek from his home state Wisconsin and the Gyllenhaal brothers were being dropped off by their father Eric, who coincidentally joined us on the Ivory Gull twitch, but sat this one out. All parties magically united on time.
We were pulling out of my driveway at 8:03 p.m. We got about ½ block away when someone asked, "did you bring the bread"? I knew I was forgetting something. I made a U-turn, pulled into my driveway, ran inside the garage and grabbed 2 garbage bags full of my emergency stash of stale bread. Off we go! We hit the road and got there in 13.5 hours. The trip was as smooth as can be - it always is on the way there and this must have something to do with all of the positive energy of a hopeful twitcher. For some strange reason, I insisted on driving the entire way. This was also the case with the Ivory Gull twitch. I don’t plan this extreme and irrational behavior but something seems to compel me. About half way there, I say to myself, “you’ve driven this far, just finish it off”. I’m not sure if it’s my fear of letting others drive or subconsciously not relying on others to get me to my birds. My wife says I feel the need to work for birds of this magnitude and so that’s the explanation I’m going with.
We got to Cherry Creek State Park around 9:00 a.m. on Sunday and got news from local birders that the Ross's was seen a little while ago on the northwest side of the lake near the marina. We set up on the beach just south of Dixon Grove on the northeast side of the lake with the sun to our backs. We began to scan. I spotted an adult Lesser Black-backed and got a little giddy about that. Then I spotted a loon which I was pretty sure was a Pacific Loon. “Chris, check out this loon in my scope”. Chris confirmed it was a Pacific – a lifer for me that held no significance at the time. I needed to stay focused. “Oh, there’s a California Gull; and another one”. I told myself to keep my eyes on the prize. “Greg, is this a Thayer’s Gull?” STAY FOCUSED!
After about a half-hour of scanning with a group of about 12 birders, I finally spotted it: “I GOT IT”!!! Birders demanded a location. I was lost for words. I was still trying to internalize that I had the Ross’s Gull in my scope. At first glance, I noticed a bird about the size of a Bonaparte’s Gull with a noticeably peaked head. The image that keeps replaying in my mind is that of a small white-winged gull on the water next to an adult Bonaparte’s. The difference in wingtip color is - and should be - noticeable to anyone who is familiar with Bonaparte's Gull.  “It’s on the water with a Bonaparte’s to its left. They’re swimming between two...what are those white tubes called that float in the water?” Buoys! “Yes, it’s between the two white buoys against the opposite shore. Wait, it's moving. It's up”! The Ross’s began to fly around with what seemed like no purpose in mind. It put down shortly after and everyone got on the bird. The ID was obvious. We debated whether or not we should hurry over to the other side of the lake but decided to wait about 15 minutes to see if the bird would come closer to us. We soon gave in and made the drive around.
We parked at the marina on the northwest side of the lake. Bruce and I made a run for it as we could see the bird standing on the famous sandbar that it made its resting station. We can see people enjoying great looks but it got up and took wing before we can reach the sandbar. It began to circle and maneuver similar to how a Bonaparte’s flies but there was something much more intriguing about this bird. It was a Ross's Gull on a small lake in Colorado! It was almost like it knew it was being watched by everyone on the lake, even by the other gulls. I walked out a distance to the east on the dam road in order to gain better lighting. It spent most of its time over the center of the lake, circling and feeding at the water's surface. It was harassed by a couple of Ring-billed Gulls and then it positioned itself in the middle of a group of Western Grebes as if to take refuge among them. It then got up again and continued to randomly work the edges of the lake. At one point it lazily flew along the northern shoreline giving Aaron and I great looks as it came within 25 yards of us.
Basic Adult Ross's Gull, Cherry Creek State Park, Colorado; 21 Nov 2010

I started to pick out important ID marks that I had reviewed the day before. Big eye on a smallish head with a short stubby bill? Yes. Grayish underwings (not black like Little Gull)? Yes. Pointed wingtips with a long hand? Yes. White secondary bar that tapers off at the mid-primaries? Yes. Observation time was short and I must admit that one thing I forgot to look for was the wedge-shaped tail. This mark is a great ID point in all plumages. Suddenly the bird began to circle back and it gave Aaron and I another close look insomuch that we could see the pink suffusion on the underparts with the naked eye.
We watched the bird for perhaps under 3 minutes at this distance when suddenly it did something very unusual. It began to ascend and circle over the lake in a manner that suggested it was going to depart. It did this twice in the course of 15 minutes and so people began to panic. In my heart of hearts I thought I watched the bird put down towards the south side of the lake and that was the last I saw of it, but I was told people watched it land on the west side of the lake, south of the marina. We decided to get back in the car and find a better vantage point from the Lake Loop parking lot. As we were getting out of the car, I commented to the group about how the sky had become very overcast and that the winds had shifted. A cold front quickly swept in and the lake began to fog up. In less than 30 minutes the entire lake looked like a scene out of Michael Jackson's Thriller video. Here is a before-and-after of the conditions on the lake. This transformation took place in the course of an hour:

The "after" photo is not in black-and-white. This is the actual color of the lake presented by the rapidly changing conditions. We started to brainstorm and thought this would be a perfect time to bring the gulls to us. Bruce brought along a few bottles of cod-liver oil that we smeared on the bread. We made our way back to the eastern shoreline and we began to chum in the gulls. We had a nice assortment of California Gulls with the highlight being an adult Mew Gull that I picked out - but no Ross's Gull.

 Adult Mew Gull (center) with California Gull and Ring-billed Gulls.

We had no solid strategy as this was the first time the Ross's had gone unnoticed for an extended period of time in the last 3 days. We made it back to the Lake Loop area and ran into a group of birders who also felt the gull had departed. One birder told us the gull was reported at 12:05 p.m. Naturally, we got our hopes up but we came to find out that this report was from yesterday...oops. As a spoiled Illinois birder, I felt the level of communication by the immediate Colorado birding community was lacking. I say this because an ABA Code-3 bird should be reported with much more detail and frequency. For instance, many reports were vague with phrases such as "bird is being seen right now". Often, no specific vantage points were suggested nor were times included in the text of the report. It should be noted that Yahoo groups are notorious for not updating correct times with their posts and so this adds to the confusion of trying to get concise reports. 

Just as fast as the weather conditions had worsened, the weather began to change and viewing conditions became ideal. The lake became calm and clear. We thought this would be our best opportunity to refind the gull. We scanned and scanned, and scanned but alas, no Ross's. Nothing but a few Bonaparte's off to the opposite shore which made for a great exercise for anyone who wanted to really reinforce the distinguishing ID marks of Bonaparte's and Ross's Gull. This was in fact the most educational part of the trip for me. 
Swim Beach looking north towards dam
More than 3 hours had passed and there was no trace of the bird. We had pretty much lost hope. Finally, after a nagging suggestion by one birder to go hit a few country roads in search of Ferruginous Hawks, I gave in. We ran into Ira Sanders (brother of long time Chicago birder, Jeff Sanders) who gave us spot-on directions for Ferruginous Hawks and Prairie Falcons. Bruce suggested that we should try the eastern shoreline one last time and we did. Nothing but Bonaparte's, Californias and the single Mew Gull. We packed up and made the 1+ hour trek to find "Ferruginous Hawks". We were successfull with 3-4 FEHAs in less than 15 minutes. We also spotted a Prairie Falcon and multiple Western Red-tailed Hawks. The sun was beginning to set and it would soon get dark. We then punished ourselves by checking the Colorado list where we read a report explaining how birders were currently enjoying good looks of the Ross’s Gull close to the dam. We were over an hour away and it was impossible to make it back to Cherry Creek S.P. before sundown. A few of us doubted the report was current but it was. The bird had been relocated and we weren't at the lake! We left the lake when we should have committed ourselves until sundown. You live and you learn. Where was the Ross's Gull hiding this entire time? One report explained that the gull took to the southeast side of the lake during the storm. This makes sense as it would have been protected from the winds that ripped through. Truth be told, this is the only section of the lake that went neglected by us due to inaccessibility.

The bird was seen by all of us and admittedly I probably enjoyed the best looks, but I've concluded that Ross's Gull is "unfinished business" for me. You might ask, what is the price that was paid for this bird: 2,058 miles and 36 hours! For some, seeing a Ross's means checking it on a lifelist and moving on. This is far from true in my case. In due time, I will have to exert more time and energy on this species. An adult in alternate plumage would be wonderful but I long to see a juvenile Ross's which is very unlikely to occur in the United States. I do feel that I will never treat a flock of Bonaparte's Gulls as just "Bonaparte's". Both Howell and Olsen mention that Ross's, just like Little Gull, are more times than not found with Bonaparte's Gulls when out of range. 
 Left to right: Aaron Gyllenhaal, Greg Neise, Bruce Heimer, Chris West, Ethan Gyllenhaal, Amar Ayyash
  As of 25 November, 2010, the Ross's Gull is still being seen at Cherry Creek S.P. The lake has risen slightly and the sandbar isn't visible anymore. Coincidentally, the Ross's has been reported on the south side of the lake near a few large stumps. This should be great for photographers as the sun is now at their backs for most hours of the day. Oh, would that I were a Coloradan today!
The best photo I've seen of the Cherry Creek Ross's Gull. By Robb Hinds; 25 Nov 2010

07 November 2010

Preformative Molt and Bonaparte's Gull

It is said that molt is the most understudied and underappreciated aspect of birds. Maybe. I remember reading a paper by Peter Pyle a few months ago where he mentions how it took him something like "ten years" just to wrap his mind around molt terminology. Wow! Over the last two years I've come to appreciate this bewildering subject and a basic understanding of the "modified" Humphrey-Parkes system has helped me understand birds just a little more. A deeper understanding of molt becomes integral when considering gulls and being familiar with the various molt strategies is a requisite for anyone with a veritable interest in this family.

Birds molt at different rates and frequencies but all generally follow one of four strategies. Determining which molt strategy (Simple Basic, Complex Basic, Simple Alternate or Complex Alternate) a bird obeys depends almost entirely on the events that take place in the first cycle.

Of the four molt strategies, the Complex Alternate Strategy (CAS) is, to me, the most unique. I have a particular interest in this strategy because it applies to all of the hooded gulls that occur in North America. Here, a formative plumage and an alternate plumage are found in the first cycle. These plumages are a result of a partial preformative molt and a partial prealternate molt.

Most birders generally know what is meant by a prealternate molt but I've found that many don't know the implications of the "preformative molt". In the past, ornithologists (including Humphrey and Parkes) overlooked the preformative molt and called it the first prebasic molt well. The juvenile plumage was not point zero in the study of molt. The former approach was easily justified because formative plumage can resemble that of a basic adult (Howell and Dunn, 2007). However, the preformative molt and prebasic molt are two different events. The modified H-P system suggests that a bird has arrived at 1st basic when in juvenile plumage. That is, the "1st" prebasic molt produces the juvenile plumage. This is nothing more than a nestling growing juvenile feathers.

The preformative molt is an additional molt that follows but is still contained in the first cycle; Unlike prebasic molts which reoccur, there are no preformative molts in any cycle thereafter.  Howell describes the preformative molt as a one-time event that acts as a "bridge" from juvenile plumage to 2nd cycle.

A good example of a common species that acquires formative plumage is Bonaparte's Gull. There are generally two waves of first cycle Bonaparte's that are observed in North America after the breeding season. The first wave begins in late July to early August and it consists of juveniles that appear to be in mostly fresh plumage like this individual:

Juvenile Bonaparte's Gull before acquisition of formative plumage; Chicago IL, 15 AUG 2010

By the end of August, these individuals become harder to detect because the preformative molt soon changes their appearance. The second and more significant wave of Bonaparte's typically peaks in late October (depending on migration routes and wintering latitudes). The first cycle individuals in this wave have concluded, or have come close to concluding, the preformative molt: 

 First cycle Bonaparte's Gull in formative plumage; Chicago IL,  2 NOV 2010

Some obvious changes have occurred but note that the juvenile flight feathers are not replaced as this is a partial molt. The juvenile tertials are still present as well. The upperwing coverts have mostly worn away their cinnamon/brown subterminal tips, but haven't been replaced. The head, neck and sides of the breast lose the brownish wash of the juvenile and this is a result of the body feathers molting. The brownish mantle and scapular feathers have also been replaced by the partial preformative molt. The bird now has an overall adult appearance. This is the stage that Humphrey and Parkes would have called 1st basic. 

If you're familiar with Jon Dunn's Advanced Video Series, then you'll note that the video on "small gulls" doesn't refer to juvenile plumage as 1st basic. It also fails to make mention of formative plumage as these videos predate the latest modifications to the H-P system. Again, a juvenile is equated with 1st basic in the modified H-P system. Although the replacement of some feathers occurs, the preformative molt should not be considered "the" gateway to 1st basic. This is a distinction that needs to be made when considering Complex Basic and Complex Alternate - the crux of the modified H-P system.

Same juvenile as first photo. Note the cinnamon-brown subterminal edging to the median/greater coverts. These upperwing coverts are not molted in the partial preformative molt. The November individual above with almost entirely gray median/greater coverts has the same upperwing coverts it had in juvenile plumage. Only now, the brown coloring on most of the coverts has faded on all but the lesser coverts; This is why a carpal bar is still evident in flight on individuals in formative plumage.  

First cycle Bonaparte's Gull in formative plumage; Carlyle IL; 14 NOV 2010

A slightly darker than average individual in formative plumage.  Note the juvenile wing and tail feathers produced by the 1st prebasic molt. The gray adult-like mantle and the white body feathers are a result of the preformative molt. In late winter, this species begins its 1st partial prealternate molt - a reoccuring molt in subsequent cycles.

I hope to follow up on this post with an explanation of the rest of the first cycle molts and plumages in first cycle Bonaparte's. Meanwhile, I'd like to recommend a few resources for anyone wishing to pursue this subject in more detail:
  • All You Ever Wanted to Know About Molt But Were Afraid to Ask, Part 1 (Birding, October 2003,pp. 490-496).
  • All You Ever Wanted to Know About Molt But Were Afraid to Ask, Part 2 (Birding, December 2003, pp. 640-650).
  • Gulls of the Americas; Howell & Dunn, 2007.
  • Identification Guide to the Birds of North America, Part 1 & 2; Pyle, 1997, 2008  
  • Molt in North American Birds; Howell, 2010.
I'd also like to leave you with one final thought that Steven N.G. Howell mentions in his latest work on molt: "We must accept, however, that even the most elegant human systems are imperfect attempts to put dynamic natural processes into boxes. There will always be exceptions. It is human nature to focus on exceptions, but to understand patterns it may be more helpful to focus on features shared by the majority of birds" (Howell, 2010). What if one day the modified H-P system is itself modified?

31 October 2010

Franklin's Front

Franklin's Gull has turned up in almost every state and province in North America. Its migration corridor in the United States is directly through the Great Plains where hundreds of thousands can be found annually. In the Midwest, Franklin's is uncommon to rare but more common in the fall. In Illinois, for instance, Franklin's Gull is left unchecked on most birders' lists in the spring due to this species' hurried nature to get to the breeding grounds. Midwestern states east of the Mississippi River have a much better chance of observing Franklin's in the fall, particularly in late October after a cold front has passed. I've learned that tracking weather systems for this species, as magical as it may seem, is for the most part reliable and predictable. The ideal parameters involve areas of low barometric pressure with a strong west to northwest wind with the passage of a cold front.

Basic Adult, 64th St Beach, Chicago IL; 27 Oct 2010
I recently spent some time researching Franklin's Gull records in the lower 48 states and I remember reading in "Birds and Birding at Cape May" by Clay and Pat Sutton, that Franklin's Gull was recorded in record numbers in 1998 at the Avalon Seawatch. This event took place after a strong low pressure system ripped through most of the Midwest and north through Canada. At the time, I remember distinctly asking myself how this record number, which to my recollection was under 50 individuals, could be associated with a low pressure system in the Midwest.

On 26-27 October 2010, the Midwest and surrounding central states experienced the lowest barometric readings ever recorded away from the sea coasts. The damaging winds and thunderstorms were likened to a Category 3 hurricane. I was on standby and waiting to see if indeed Franklin’s would pass through with the cold front. The night before, birders Bob Hughes and Michael Retter explained how the conditions were ideal for Franklin’s via the Illinois Birders’ Forum. Sure enough, as the cold front passed through the Midwest, reports of Franklin’s Gulls began to pour in.

Illinois, Indiana, Michigan, Ohio and Wisconsin all reported Franklin’s Gulls on 27, 28 October, 2010. My home state, Illinois, reported at least six distinct sightings with the 64th St Beach along Chicago’s lakefront tallying a site-record of 47 individuals (Paul Clyne). Wes Serafin reported a group of 20+ at Saganashkee Slough, an inland lake in southwest Cook County, IL. Ohio reported a flock of 29 at Caesar Creek Beach. Caesar Creek is in the southwest part of the state where only 1-2 individuals are recorded in the fall (Larry Gara). And if one needs more evidence that this was no fluke, New York also recorded two individuals as far east as Suffolk County (far eastern NY). Keep in mind that Franklin’s is casual to very rare along the Atlantic coast (Howell and Dunn, 2007). Did the birds intentionally avert the storm by shifting their migration route eastward or did the storm blow them east as they were migrating? Regardless, the conditions inherent in these storms are what I’ve come to call “Franklin’s Fronts” - experienced birders await them and expect to see Franklin’s Gulls trailing behind.

I found some time to make it out to the 64th St Beach in Chicago on 27 October, 2010. The winds that day were like none I've experienced on the lakefront outside of winter. The Saganashkee Slough flock was seen leaving in earnest at sunrise the next morning; This is typical of moving flocks of Franklin's, rarely dwelling for more than a day or two away from established staging areas.

All photos were taken on 27 Oct 2010 at 64th St Beach

12 October 2010

Franklin's Passage Through Iowa

Every fall, thousands of Franklin's Gulls descend on the Des Moines River Valley corridor in central
Iowa. Numbers increase in earnest as soon as the fall season begins, peaking in late September and through the first couple of weeks of October. The most notable massings are found at Saylorville Lake (the famed Midwestern lake that hosted the 2007 Black-tailed Gull) and Lake Red Rock (Iowa's largest lake).

Both resevoirs were built by the Army Corps of Engineers to control water levels along the Des Moines River Valley
Olsen and Larsson note a maximum record of 37,480 Franklin's Gulls at Saylorville Lake in October of 1998.  Average counts range from 9,000-12,000 at Saylorville and 12,000-15,000 at Red Rock (Dinsmore per comm.). Both resevoirs are situated about 50 miles apart and they're used by the gulls primarily as an evening roost.

As a denizen of the Chicago area, I had never observed more than 3 Franklin's at once and so I planned a trip out to these lakes in order to better familiarize myself with the "Prairie Dove". An obvious observation that I soon made was that the Franklin's are not very interested in the fish that the lake holds, but rather, this species hawks the area skies for insects. Also, hundreds of individuals can be found working the recently plowed agriculture fields. The birds begin to disperse soon after sunrsie only to return as the sun begins to set. Any description I offer to describe this spectacle would be deficient at best. Here's a photo that depicts this magic!
Saylorville Lake, by Amar Ayyash, 10 October 2010
I arrived at Saylorville before sunrise and watched the sun gradually peek over the treeline. I gave the lake a once-over from the dam and spotted a sizable group of Franklin's on the beach at Cherry Glen. I drove around the lake and found my way to this flock in under 30 minutes. The gulls were engaging in what seemed like their morning ritual of preening and stretching their wings. Needless to say, there was no shortage of calling Franklin's as I approached the beach. I categorized their sounds as noticably higher pitched than Laughing Gull with a yelping quality that reminded me of Short-eared Owl.

With the sun to my back, I began counting the number of individuals with a pink suffusion on the underparts. I was a little disappointed with what seemed like a low ratio of 14:378. Franklin's consistenlty show this pink coloration much more than other gulls (Ross's Gull is a close 2nd). What I soon discovered after returning home is that this pink blemish is most common in breeding-condition adults; This is coupled with reddish legs and the reddish bill found on breeding birds.
Compared with the two Ring-billeds in the bottom right, Franklin's is a small, short-legged gull with a relatively darker mantle

As they began to take wing I noted what seemed like proportionaly befitting wing lengths for this diminutive gull.

The wings are broad with relatively rounded wingtips that could be somewhat likened to those of Little Gull, especially when they're held down.

The body is plump and barrel-like. The tail is short and the head is sunken with a short-neck appearance.

The thick eye-crescents, straighter bill and extensive white to the wingtip pattern should readily separate this species from Laughing Gull. The two are superficially alike and after close observation, one should not have any difficulty telling them apart; Franklin's should always have a fuller hood appearance in all basic plumages.

In my opinion, the most difficult ID issue with Franklin's and Laughing would be a fleeing juvenile in flight:

Top photo: Juvenile Laughing Gull, Salton Sea, CA; 9 AUG 2010
Bottom photo: Juvenile Franklin's Gull, Saylorville Lake, IA; 10 OCT 2010

Note how the Laughing Gull's underwing linings are duskier with marked flanks and a brownish collar around the neck. Franklin's shows white on the outer undertail feathers unlike any juvenile Laughing Gull. I do think these plumage features are less important than size and structurePlumages vary - proportions, more often do not. Take for example this juvenile trailing immediately behind the Ring-billed on the left:

This heavily marked juvenal is a result of a delayed partial preformative molt. The dusky underwing, flanks and collar are not commonly encountered this late in migration. The size of this individual easily eliminates Laughing.

I estimate that over 3/4 of the Franklin's Gulls at Saylorville and Red Rock are adults that have completed (or very close to completing) their prebasic molt. I ended my day by observing hundreds and hundreds of gulls pour in over the dam to roost on Red Rock. My count totals, based on select sample blocks, were 6,800 at Saylorville and 9,500 at Red Rock. 

As I headed home and drove east on Interestate 80, I came to the realization that Franklin's Gull will probably never be found in numbers east of the sites I had just explored. The smattering of sightings that are reported east and west of the Great Plains is really insignificant when one considers the hundreds of thousands that funnel down through parts of Kansas, Oklahoma and Texas. A recent correspondence with Kansas birder Chuck Otte revealed this, "Amar, here at Milford Lake (near Junction City, Kansas) I see all of the things you mentioned. They spend the night on the lake and I honestly feel that the overnight numbers at this time of year have to be approaching 200,000 to a quarter million". Tom Shane who lives in Garden City, Kansas wrote this, "We live in western Kansas and are excited to get just one Franklin's Gull".  This truly speaks to how narrow the migration corridor is for this species!

01 October 2010

Sabine's Gull - Carlyle Lake, IL

Every fall in late September, the Illinois Ornithological Society (IOS) offers an "inland pelagic" field trip to Carlyle Lake, with Sabine's Gull being the primary target bird. Carlyle Lake is the biggest inland reservoir found in Illinois and has indisputedly provided more state records for this species than any other site. More so, Carlyle now produces more Sabine's Gulls than Miller Beach in Gary, IN. Ken Brock predicted this over a decade ago in his Sabine's Gull paper that assessed this species' footprint in the Midwest:  "Although Gary, Indiana at Lake Michigan's southern tip currently boasts the largest total, based on current observation rates Carlyle Lake will claim the title in the near future (Meadowlark, V7 N1)". I'm unsure of current data, but if I had to make a prediction as to which state will claim the title next, I would put my money on Iowa, particularly from the large reservoirs in the Des Moines River Valley area (Saylorville and Red Rock Lakes).

Anywho, the IOS trip to Carlyle finds birders traversing the lake for several hours using a flotilla of 2-3 pontoon boats. Bread and popcorn is used to chum the gulls and eventually a Sabine's is discovered by one party which then alerts the other boats.

This year, I had the pleasure of attending this field trip for a 2nd time and I was not dissapointed in the results. In fact, I've attended this trip the last 2 out of 3 years with Sabine's gone unrecorded on the trip I missed. Are you thinking what I'm thinking? Yes, I should attend this trip every year so that other birders get a chance to see this species :) Tim Kussel for instance, has had a 4 out of 8 success rate and so it's not gravy every time you get on those boats.
Our search for Sabine's Gull took less than 30 minutes when one of our crew members, Anthony Friend, spotted a Sabine's flying right towards us. As expected, the bird was a juvenile that was probably no more than 3 months old. I should mention that in Brock's data from 1998, out of 111 aged birds, only 13 were adults. These numbers should have significant meaning to the vigilant birder (not I).

Juvenile Sabine's Gull by Amar Ayyash, Carlyle Lake IL, 25 SEP 2010
Same individual as above.
The day ends with an evening lakewatch from the Hazlet Olympic Pavillion on the west side of the lake. Here, we were again treated to extensive but somewhat distant views of two Sabine's feeding out at mid-lake with hundreds of gulls, tens of Black Terns and a Parasitic Jaeger. An interesting observation that I won't soon forget is the feeding style of this agile gull. While flying low, it would bank and come to a sudden stop where it would  then dip to snatch its food from the water. I commented to the folks around me that the behavior was very tern-like, although the wing-beat pattern was much more stiff compared to a Bonaparte's Gull or Black Tern.

Last month, I was reflecting on the uniuqeness of Sabine's Gull's molt strategy but I failed to put two and two together when watching this species from the Olympic Pavillion. For a brief moment, I thought I may have had an adult Sabine's out on the lake. I kept this thought to myself and studied the bird a bit more. Lighting conditions were less than ideal and from afar the brownish/gray mantle seemed solid gray as expected in an adult. There is no parallel as in the adult/juvenile Black-legged Kittiwake or adult/juvenile Bonaparte's when it comes to the upperpart pattern of Sabine's; Both ages are virtually identical from above.

The smoky wash to the nape and breast was undetectable to my inexperienced eyes. Since the bird I was watching did not have a black hood I thought, "Oh, why can't that be a basic adult"? Although knowing what to expect from earlier in the day during the boat trip, I squinted and squinted until I made out the thin tailband. The tailband was very hard to make out and I think that if lighting conditions were any worse, and had I not had a biased expectation from a few hours prior, I may have missed it completely.

Fortunately, a most humble birder from St. Louis rightfully reminded birders of Sabine's molt strategy in a recent thread on the Illinois Birders' Forum (IBF). Unlike other gulls that breed in the northern hemisphere, Sabine's is a high-Arctic breeder with a taxing migration. It does not have the time and energy to manage a complete prebasic molt on the breeding grounds or en route while migrating. Rather, this molt is delayed, or "suspended", until it arrives at its wintering grounds. Although limited head and body feathers may be molted during migration, an adult Sabine's seen in the interior states in fall will almost always have a full hood effect. In fact, Olsen estimates that over 90% of Sabine's Gulls seen in the northern hemisphere will have full summer hoods from August through early October. This implies that one should expect to see one of two plumages in Illinois: First Basic or Definitive Alternate, with the latter being much less common.

Note the black subterminal tailband, dusky ring around the neck, scaling on the 
contrasting mantle and secondary covert feathers.

Full hood with black border, solid gray mantle, white tail and tips to primaries.

My two photos above are somewhat of an oversimplification that may give the impression that identifying these two ages is a nonissue. Maybe, but not when viewing conditions are less than ideal and more than 1/2 a mile sits between you and this agile -sometimes erratic - flying beauty. I know this from firsthand experience (i.e., my mistake).

From the Olympic Pavillion out to mid-lake, using a 60 power scope, one
could expect to make out less detail than what is seen in the photo above.

It should also be mentioned that any sighting of 1st summer birds is considered extraordinary and quite rare. These sightings should be well documented since it's believed that this age group remains primarily on or around the wintering grounds without migrating through the interior. I'm currently discussing a bird with Indiana birder Mike Clarke who observed a Sabine's in the Bloomington area on 30 SEP 2010. He describes a bird with no juvenile-like dusky wash on the neck and sides of the breast, a medium-gray manlte and an all black bill. The bird had no adult hood but had an extensive white area on and around the neck as a 1st summer bird. Could this be another distant juvenile? It was observed at less than 1/4 of a mile in excellent light with a 80 power scope.

  A more serious ID issue is confusing young kittiwakes with Sabine's in flight. Keep in mind that Black-legged Kittiwakes form M-patterns through their ulnar bars and Sabine's does not.

Photo by Amar Ayyash
Photo by Ross Ahmed

This photo is a great picture, but I don't expect on seeing these specieis side-by-side. In the Great Lakes region, Sabine's is an earlier transient than Black-legged Kittiwake, with little overlap. However, one never knows what to expect. Last year, there was an early Black-legged Kittiwake sighted in September at the confluence of the Illinois, Kankakee and Des Plaines Rivers. While searching for the kittiwake the next day, birders happened upon a Sabine's Gull.  

Thanks to St. Louis birder Charlene Malone for forcing me to review the particulars that make Sabine's such a special gull. I hope to be watching Sabine's Gull tomorrow with thousands of Franklin's from the dam on Saylorville Lake in Iowa. I'll have to quiz those Iowa birders on "expected plumages in the Midwest". That's all for now.
A plumage not familiar to the interior states: http://www.youtube.com/watch?v=T9s-qVJly-M&feature=related

A juvenile in flight:  http://www.youtube.com/watch?v=aj_jK9LNQ1Y&feature=related

29 August 2010

The Yellow-footed Gull at The Salton Sea

In the United States, the only reliable location for Yellow-footed Gull (L. livens) is the Salton Sea in southeastern California. Here, there is a sizable post-breeding dispersal from the Gulf of California, usually beginning in late May to early June, and peaking in late July to early August. Peak numbers can be anywhere from 100-300 individuals of varying ages, with adults slightly predominating. Numbers start to gradually decrease through the fall with only a handful lingering through the winter (particularly, at the southeast unit of the sea). By the time the CBC rolls around, birders must really put in an effort to find 1 or 2 individuals hanging around Obsidian Butte. Wintering individuals are usually first-year birds.

The Yellow-footed Gull was once considered conspecific with the Western Gull (L. occidentalis). When looking at the aggregation of differences among YFGU and WEGU one begins to wonder how these two taxa were ever treated as the same species. James Audubon is responsible for originally making this classification and both Ridgway and Dwight perpetuated the idea, agreeing that Western Gull has a northern form and a southern form -- the southern form being L. o. livens. This classification was made solely on the fact that these two are the only large gulls with dark mantles on the west coast. It is however important to add that Yellow-footed Gull has never been known to occur regularly on the Pacific Coast of California. There are only a handful of records along California’s coast. With regards to the Pacific, Yellow-footed Gull only occurs at the very southern end of Baja California’s coast. In other words, the two are geographically isolated and there is no record of interbreeding; Audubon, Ridgeway and even Dwight were unaware of this isolation in ranges.

Alan Brooks was among the first to question this grouping with his paper, “What Color are the Feet of the Western Gull?". In 1982, 60 years after Brooks' paper, the AOU split the two after Pierre Devillers demonstrated that Yellow-footed acquires definitive plumage in 3 cycles and Western in 4 cycles. In addition, the differences in leg color, voice and nest site preferences clearly warranted a split. The Yellow-footed Gull has a much more lower pitched voice when compared to the almost yelling high pitched tones of Western Gull. Also, Yellow-footed prefers to nest parallel to the tide line on beaches whereas Western prefers higher elevations. I tried to play devil's advocate and found examples from modern day classifications where accepted subspecies are known to show some of these variations.

According to Olsen and Larsson, the nominate race of Lesser Black-backed Gull, Larus fuscus fuscus, is a "three-year gull" whereas L.f intermedius and L.f graellsii are "four-year gulls".  With regard to leg color, a sizable percentage of the East Baltic race of European Herring Gull (L argentatus) has yellow legs as opposed to the the pinkish legs of  the western race. Also, various races of the Herring Gull complex exhibit noticeably different voices. Although unlike WEGU and YFGU, the two races of Herring Gull commonly interbreed when they come in contact. Judith Hand argued that the two, Western and Yellow-footed, have environments that "differ radically" and that although there is no reason to believe the two would not interbreed if they came in contact, how successful such interbreeding might be is another question (Hand, 1981). Hand's statement makes sense considering WEGU and YFGU nest at differing elevations with colonies that are clustered versus linear, respectively. She also argued that interbreeding is certainly not enough to warrant a lumping of any sort, giving the example of L.glaucescens and L.occidentalis.

Having found examples of current gull classifications of where molt cycles, leg color and voice vary among subspecies, I've come to my own conclusion that Devillers' research was not "the" determining factor that brought about the split, but rather, it was the aggregation of differences that many ornithologists had been pointing out since almost immediately after the classification was made by Audubon. Although I'm sure Devillers' work was the straw that broke the camel's back.

I spent a couple days birding the Salton Sea earlier this month (August, 2010). Most of the birds I observed were in heavy molt but I did have the opportunity to observe the various ages of YFGU. I made it a point to spend time observing plenty of Western Gulls along the coast before and after my Salton Sea visit. As I was getting out of my car and changing into my mud boots, I heard an interesting vocalization from the beach that I had never heard before. The only gulls on the beach, as it appeared, were Yellow-footed, California, Ring-billed and Laughing. Having heard the latter three before today, I suspected that the voice I was hearing was that of Yellow-footed. The voice was very distinct: deep, low pitched and somewhat eerie. Indeed, it was an adult Yellow-footed Gull -- ruler of the beach!

Presumably a female on left and male on right.

My lifer Yellow-footed. This is the first individual my eyes met as I drove along the levee road.
Adults are easily separated from Western Gull by leg color. Although, on two occasions during my visit, I watched adult Yellow-footeds fly away with their legs dangling under their tails. The shadow from their tails obscured the yellow color on the feet and legs, resulting in what both Guy McCaskie and I swore was pink. We realized this was a lighting effect playing tricks on our eyes. 

What if the birds are sitting or in the water? There have been more and more isolated sightings of Western Gulls at the Salton Sea. This could make for a great ID challenge. Consider the two birds below:

The top bird is a Western photographed in San Diego and the bottom bird is aYellow-footed photographed at the Salton Sea on the same day.

What is more of a challenge is telling apart the younger-aged individuals. When looking at first cycle birds, notice that Yellow-footed has paler underparts and an obvious white patch on parts of the belly:

 This is very different than a 1st cycle Western that has an overall much darker, chocolate-brown aspect:

A nice mark on 2nd cycle Yellow-footeds is the almost complete lack of barring on the upper-tail coverts. Usually a solid black tailband is distinctive:

Younger Westerns are typically found with heavy markings and barring on the undertail coverts -- at least much heavier than a typical juvenile or first cycle Yellow-footed:

1st cycle Western Gull

1st cycle Yellow-footed

Some will say that Yellow-footed is generally a bigger bird with a heavier bill when compared to Western. This is true, but when considering age/sex differences, I feel these are not helpful ID points. Something else to keep in mind is that subadults do sound similar. It is mainly in adults that a voice difference becomes noticeable.

The Salton Sea can be an incredibly grueling place to bird and is not meant for the faint of heart. I had the pleasure of birding the Sea with the godfather of California birding, Guy McCaskie, who is unquestionably the authority on avian life here. Much of the information in this writing came from Guy per. comm. He was very clear about making sure to have lots of water and a full tank of gas when I came back to bird the sea on my own. He also pointed out some areas where he explicitly said, "You see that muck? Don't go near it or you'll end up neck-deep in it before you know it". I spent hours here on my own and I have to say there is a somewhat eerie feeling to birding here. I'm not sure if it was all of the dead snags, the 110+ degree temps I had been hearing about for months or the Horse-flys that bombard you as soon as you get out of your car:

Perhaps it was the scare I got when I spent about 2 minutes in quicksand, having to surrender my New Balance gym shoes. I thought for sure I was toast!!! Those were maybe the longest 2 minutes of my life. I wiggled my way out and tried not to panic while sweat dripped from every pore of my body. Guy's words of being "neck-deep" somehow reemerged in my memory only after I started sinking. The terrian looks completely traversable and then suddenly you begin to go down in what feels like muddy sand. It's said that if you don't see footprints or tire tracks before you, then don't go any further.

Photo by Mary Beth Stowe

During one of my visits at the Sea, I spent about 5 hours at Obsidian Butte and never once saw or heard another human being. It was a tranquil session of just me and the birds!

Obsidian Butte

The long call of the Yellow-footed Gull still resonates with me when I look at these photos. My mission was accomplished. I got the Yellow-footed and got out of dodge!

All of the gull photos in this post were taken by myself between 6-11 Aug 2010. The Western Gulls were shot at J St Marina and Camp Surf; The Yellow-footed Gulls were photographed between Red Hill and Obsidian Butte.