26 November 2011

Ohio Black-tailed Gull: Take Two.

Every birder has experienced it - you score a life bird but know in your heart of hearts that the looks you got were "crappy", bordering on unidentifiable were it not for expectations. On Sunday, November 20th, I drove out to Ashtabula Ohio for their first state record of Black-tailed Gull (Larus crassirostris). It was found by Ohio birder Craig Holt a few days prior on 16 November. I got to Ashtabula and found the bird around 8:00 a.m. YES! LIFE BIRD! The looks I had were very brief as I watched it preen in the water for about one minute, standing from an elevated bridge, looking into a channel some 400 yards away.

I was really excited when it got up as the black tail sealed the ID for me, but it continued in the opposite direction. It flew off to the northwest. I knew I was in trouble as this bird had the habit of disappearing early in the morning with no particular pattern. This sort of birding is agonizing. If one misses that short window in the morning, they may be "tethered" to that site for the rest of the day. I waited for it to return for almost 3 hours before I gave up and moved on. I bummed around various harbors and river mouths in the area and then drove home, a drive a little less than 6 hours. The entire experience was bittersweet: "I'm not happy with those looks", I thought.

I decided to go back 4 days later, but this time, I took the advice of Ohio birder Jen Brumfield, who advised we get there before first light. We did. Andy Sigler, Chris West and myself got there about an hour before sunrise and waited. We started scanning the channel, literally, at the crack of dawn. It was still dark out but we were able to make out the silhouettes of perhaps 2,000 gulls in the channel to the north. A Carolina Wren gave a morning murmur from the overgrowth below the bridge. Within a few minutes, the gulls started to move over the bridge and into the marina area along the river. I walked down the bridge and situated myself at the marina where I began chumming. The Ring-billeds responded well. I thought that if the Ring-billeds caused enough commotion, the Black-tailed would fly in to investigate.

Sure enough, less than 10 minutes later, Chris West skillfully spotted the bird in flight. It flew over the bridge and landed at the river mouth with the hordes of Ring-billeds. Chris shouted maniacally, waving and pointing to where I presumed he had the bird. I couldn't make out what he was saying nor could I see the bird, although it wasn't too difficult to tell that he had good news! He ran down to where I was and quickly relocated the bird a second time for me. Once I got on it, I kicked myself for not being able to see it. It sat in the water about 200 ft away and never showed any interest in my bread offerings. My mind was expecting a larger and darker bird but this was not so:

Adult Black-tailed Gull with Ring-billed. Ashtabula, Ohio; 24 NOV 2011.
I'd like to share a few identification notes here. Notice how the body size matches Ring-billed, almost exactly. Lesser Black-backeds are notably larger, but admittedly, this point could be useless if there isn't another gull nearby for comparison. The upperparts are typically a shade paler than Lesser Black-backed but could easily show some overlap. Black-tailed Gull is unarguably darker than the darkest California Gull. Keep in mind the ramifications of lighting when it comes to upperpart coloration. The wing extension is long and sleek like Lesser Black-backed but the bill is closer to that of California Gull. Note the long, parallel-edged look to the bill with a black subterminal tip. Better photos would reveal a significant amount of red on the very tip of the bill. I think the bill on this species is just as important an ID point as the tail. The clean white head pattern on this individual is a bit unusual. Most Black-taileds observed in North America have moderate streaking towards the back of the head. Here's a diagnostic shot of the tail:

Black-tailed Gull. Note the significant width of the white terminal edge to the tail.
 Photo by Chris West.

We spent the rest of the day birding various lakefront sites with Lorain Harbor being the highlight. Lorain is credited with Ohio's only Heermann's Gull and Tufted Duck records. We had hoped for a Little Gull or Black-headed but shamefully couldn't find one in the oodles of Bonaparte's. We estimated the massing at about 10,000 - that's 3,000 less than what was reported the day before:



The waters of Lake Erie are a major staging area for Bonaparte's in the fall. Numbers peak in late November where aerial surveys have estimated 100,000+ of these tern-like gulls over the lake (McCormac, 2011). This is much different than the western Great Lakes: Superior and Michigan. The reason for this huge gathering of Bonaparte's is no other than an abundant supply of shiners and shad which are commonly found at the mouths of rivers as they feed into the lake.

1st cycle Bonaparte's. Lorain Harbor, Ohio. 24 NOV 2011.

Most entertaining was watching an adult with a full hood. It's not unheard of to see an adult with a mixed up molt schedule, although this was my first time personally observing a full hood in the fall:

Adult Bonaparte's with full hood in November.
It didn't take too long for it to swallow this entire shad.
Other birds of note here included a first cycle Franklin's, an adult Thayer's, an adult Lesser and up to 10 Great Black-backeds.

We then drove to Huron Harbor which is a fun little site with enough birds to hold its own. Huron Harbor has attracted a nice list of rarities in the past, including Spotted Redshank and Northern Gannet. There were "only" about 1000 Bonaparte's here with a few Lessers mixed in (two 2nd cycles and a 1st cycle).

2nd cycle LBBG. Huron Harbor, Ohio; 24 NOV 2011.

Of great interest to me was this adult Ring-billed with orange patagial tags:

Huron Harbor, Ohio; 24 NOV 2011.
This bird was tagged at Dime Pier in Chicago in 2007. To read more about these patagial tags, click here. Whether this bird spent the summer in Chicago or on Lake Erie is a mystery, but I recently found out that some of these Chicago Ring-billeds have been seen on Lake Erie before.

Same bird as above.

All and all, it was a fruitful day with better looks at my "lifer" Black-tailed and hordes of gulls everywhere we went. Something tells me I'll be going back to Lorain soon!

16 November 2011

Color-tagged Ring-billeds in Chicago

In the spring of 2007, the City of Chicago and the USDA Wildlife Services conducted a study on two Ring-billed Gull colonies in Chicago, IL. The study was an egg-oiling project initiated by the City. The goal was to determine whether oiling eggs during the nesting season would reduce the number of gulls on local beaches. Ordinary corn oil is one way to prevent oxygen from penetrating the eggshell, thus preventing the young from ever hatching. Adult parents continue to incubate and invest energy in nesting, but to no avail. This is, as one of my friends put it "murder in a non-lethal way".  

What would be the rationale in decreasing the number of Ring-billeds on the lakefront?

The primary reason given by the City of Chicago is that fecal deposits of gulls have long been one of the causes for increased E.coli levels in near-shore waters along the lakefront. The aim was to track the movements of birds that had their eggs oiled (or not) and to determine if they would abandon their respective colonies.

During the nesting season of 2007, some gulls were part of a control group (eggs not oiled) and some were given treatments (eggs oiled). Colored wing tags (patagial tags) were attached to both wings of 724 gulls from the Dime Pier colony (approximately 3,100 nests) and the Lake Calumet colony (approximately 31,400 nests). From the Dime Pier colony, 94% of the nests were oiled (7,396 eggs) and from the Lake Calumet colony, 48% of the nests were oiled (41,753 eggs). The tags attached to the local Ring-billeds consisted of four different colors: blue, green, yellow or orange.

Adult Ring-billed. Montrose Beach. Chicago, IL; 2 November 2010.
This individual had its eggs oiled at the Dime Pier colony (directly south of Navy Pier). Photo by Amar Ayyash.

I've summarized the project's methods in the tables below:

Lake Calumet Colony


Tag Color
Male
Female
Adult
Hatch-year
Blue (eggs not oiled)
71
81
152
70
Yellow (eggs oiled)
70
80
150
Dime Pier Colony

Tag Color
Male
Female
Adult
Hatch-year
Green (eggs not oiled)
75
53
128
75
Orange (eggs oiled)
78
72
150


Same adult as above.  The irony of this sighting is that this bird was found just miles from where it once attempted to nest. Even more interesting is that it was found along the lakefront more than 3 years later. So technically, it could be safely aged to "at least" 6 years old.

The findings of this study were not instantaneous since subsequent hatch-year numbers had to be reviewed. Data was collected by biologists with the USDA Wildlife Services from April of 2007 through April of 2009. During this time, the public was called on to report any tagged gulls. The USDA used press releases and online announcements to garner the input of many birding organizations. Resightings were reported from some twenty different states (and one Canadian province). Unsurprisingly, many of the winter resightings came from the Gulf Coast states; this agrees with earlier studies regarding the movements of Ring-billeds on the Great Lakes (Gabrey, 1996). Also of interest to me is that no tagged RBGUs were reported in Chicago during the winter seasons. This reinforces my suspicion that Chicago Ring-billeds are replaced by a different population during the winter months.   

Resightings of tagged birds:
Tag Color
2007
% of total tagged birds
2008
% of total tagged birds
2009
% of total tagged birds
Yellow
Orange
21
29
16.5
60
96
52.0
18
35
13.5
Blue
Green
12
6
4.0
15
31
17.1
7
8
5.0
Interestingly, there was approximately a 3 to 1 ratio of yellow and orange-tagged resightings over blue and green-tagged birds. Why this color bias existed is still unknown.The biologists and volunteers who conducted regular spot counts at the breeding colonies (at least twice per week) also recorded a similar color bias.  

Having reported two of these tagged gulls myself, I felt obligated to get details about this program and so I contacted the Supervisory Wildlife Biologist from the USDA, Thomas W. Seamans. It seemed odd to me that a relatively small percentage of the control group was reported, while a much, much, greater amount of resightings came from the treatment group. This struck me as backwards! Seamans admitted that "there is a problem with this marking technique [patagial tags] that could really cause a misinterpretation of data collected by biologists". He also added that "if we had been looking at long term movements then it [the tagging program] would have been a problem".

It's important to keep in mind that no hatch-year birds with wing-tags were reported during the breeding season of 2007 (nor were any reported the following year when they could still be distinguished from adults by plumage). In fact, not one tagged subadult was ever reported by the public or recorded by the Wildlife Services team throughout the entire project.

Incidentally, Steve Ambrose and I found an adult with a blue tag last weekend at Monroe Harbor in Chicago. Blue-tagged birds were part of the control group with no oiled eggs. I proudly reported this bird to Seamans and he was, as usual, very helpful in entertaining my questions. My resighting was only the eighth report this year and the fact that I found a blue tagged bird "makes for a rather rare sighting"! Naturally, as time progresses, less and less of these birds are being reported - some are losing their tags and some are perishing. 

Monroe Harbor. Chicago, IL. 12 November 2011. The tag on the right wing was missing. This individual could have been a hatch-year bird when it was tagged or an adult. The swollen left tibia and notably short legs make for a somewhat abnormal looking Ring-billed.
Over 97% of the nests with oiled eggs from the 2007 breeding season effectively failed. Nests that were not oiled did not suffer any "complete" clutch loss (Rader, 2008). One might argue that the City of Chicago was not trying to eliminate the entire population of both colonies but I would beg to differ. The only reason why a good percentage of nests were left unoiled in the Lake Calumet colony is because the City would have exceeded the Federal and State permits for the project (the City underestimated the number of nests on its permit application).  

I personally think the City acted disingenuously. Were they really interested in "understanding" the movements and/or reactions of the gull colonies during the breeding season of 2007? My feeling is that they wanted a quick fix to eradicate the RBGU numbers along the lakefront and they partially succeeded in doing that, but only temporarily. Their decision was rash, insensitive and ultimately a waste of taxpayer dollars. No gulls were tagged during the 2008 and 2009 breeding season and it seems like no follow-up was given to the "study". 

I'll leave my readers with one last thought from the Wildlife Services' report: "Negative effects on tagged individuals or response to tag color by conspecifics will contribute to biased results and, possibly, poor management decisions" (Seamans et al., 2010). 

I'd like to thank Thomas W. Seamans for all of his helpful information and feedback. Tom was very forthcoming and open about these findings.

12 November 2011

A Tail of Two Streamers

A couple of years ago, I noticed a 1st cycle Bonaparte's Gull with what appeared to be longer central tail feathers - longer than the rest of the rectrices. I figured this was just a unique case but kept note of it. With time, I began noticing more and more of these individuals that show this excess length. This slight protrusion sort of resembles the short streamers found on some juvenile jaegers. Here's an example:

1st cycle Bonaparte's Gull. Carlyle, IL. 14 Nov 2010.

I found it odd that the width of this excess feathering was unlike the rest of the thin, white, terminal edge to the tail. I thought that perhaps this was a trait found on some, but not all, 1st cycle Bonaparte's. I speculated that the central tail feathers grew out longer so as to "maybe" act as coverts for the closed tail from above. Afterall, these tail feathers have to last for almost an entire year.

Then, last week, I found an adult with this tail pattern at Calumet Park along the Chicago lakefront:

 Calumet Park. Chicago, IL. 5 Nov 2011.
For a fraction of a second, one has no choice but to associate this tail pattern with that of Ross's Gull. I tried finding a description or illustration of this phenomenon in the literature, but nothing. How could Dwight, Grant, Howell & Dunn, and Olsen & Larsson all have missed this? It was then brought to my attention that the Crossley ID Guide shows an alternate adult Bonaparte's with this pattern. Whether Crossley intentionally inserted this image in his guide is unknown, but the individual shown shows a pattern much similar to Ross's; had I been doing a "tail quiz", I seriously would identify it as the tail of a Ross's. Also, one can see that on that bird the outer tail feathers are quite worn and this adds to the "wedge-shaped" pattern.

Killian Mullarney from Ireland suggested that what I'm seeing may actually be the longest undertail coverts as he has seen Black-headed Gulls like this before. Incidentally, while out photographing gulls yesterday, I came across this 1st cycle Bonaparte's:

1st cycle Bonaparte's. Hammond, IN. 11 Nov 2011
Note how the undertail coverts (white) line up with the edge of the tail, overlapping with the black tailband.
The contrasting black tailband and white undertail coverts are easily delineated. From this photo, it's not very difficult to believe that the, central, undertail coverts could grow out pass the tail. This delineation would not be as clear with an adult (or 2nd cycle) since the rectrices are all white by then:

2nd cycle BOGU. Note how the center of the tail shows a protrusion - this is a result of the longer undertail coverts.

  So, I went back and reviewed more photos of the adult from 5 November 2011:

All of the rectrices are easily seen here except for the two central feathers. The undertail coverts (utc) are doing exactly what coverts do: they're covering the bottom of the tail.
The undertail coverts clearly project pass the terminal edge of the tail. From above, the straightened tail looks like this:

Undertail coverts projecting pass the two central tail feathers. This gives the impression that the central tail feathers are longer than the rest of the rectrices, although this is not the case.
I'd like to thank those who emailed me with comments on this topic, especially Killian Mullarney. My next question is: "Do Ross's Gulls, to some degree, exhibit a similar pattern"? 

Please feel free to email me your comments and observations: amarayyash@yahoo.com

Hybrid Laughing x Ring-billed

While out gulling at Calumet Park on Friday, 11 November 2011, I noticed a Ring-billed sized gull with slightly darker upperparts. I stayed on the bird for a few seconds and quickly picked up on the reddish bill:

Putative Laughing x Ring-billed hybrid. Calumet Park & Stateline Power.
This is the same presumed hybrid that has frequented Chicago's far southeast side and Hammond Indiana for the last 8 years. We've come to call him (or her) "the colonel" because it was first found in the parking lot of KFC. Here's what it looked like exactly 8 months prior:

Calumet Park. Chicago, IL; 11 March 2011.
The reddish bill, single mirror and olive-yellow iris all suggest this is the same individual. This is the first time I've seen this bird without a hood. Interestingly, the same hybrid combination is reported in American Birds from Kentucky Dam on 26 FEB 2011. Could this be the same bird?

Other gulls I observed today include this continuing 1st cycle Thayer's:
First found at Calumet Park on 5 November 2011.
Also actively feeding on minnows behind Stateline Power were 6 Bonaparte's Gulls:
Last week's birds were aged as 5 adults and 1 2nd cycle. Interestingly, this week's are aged as 5 1st cycles and 1 near adult.
Herring Gull numbers continue to increase, but there also seems to be some turnover here with this species compared to last weekend. I observed many 2nd cycles this week as opposed to the adults last week. The discharge behind Stateline Power held about 10 Herrings that seemed to have figured out the minnows there are easy to catch.

05 November 2011

FOS Thayer's Gull at Calumet Park

I officially kicked off the start of my white-winged gull season today with a 1st cycle Thayer's. I got off to a late start after having slept in with consequence. I had an important appointment at 2:30 a.m. but overslept. This almost never happens to me. In fact, it has never happened to me! Oh well - life must go on.

I got to Chicago's southernmost lakefront park, Calumet Park, a little before noon and walked out to the fishing pier. Much to my delight, the gulls came in with haste today. When not on one of the two beaches, the larger gulls usually come in from the breakwall out on the lake in Indiana waters, or south of the park, from Hammond:

1st cycle Thayer's Gull (left) with adult Ring-billed Gull (right). Calumet Park, Chicago IL; 5 NOV 2011

The bills on these young Thayer's always seems big to me, suggesting American Herring Gull, but the silvery underprimaries and venetian-blind effect to the upperprimaries are unmistakable. Overall, Thayer's is a neater looking bird than Herring. The upperparts are more neatly patterned and the underparts have a velvety look to them.

The dark outer webs and paler inner webs to the primaries eliminate American Herring.
 Note the juvenile scapulars with pale edges. This species has a somewhat frosty look compared to Herring.  
Surprisingly, 6 Bonaparte's Gulls (5 adults, 1 2nd cycle) came into the bay and allowed great looks! This is somewhat unusual on the lakefront and exceptional for Calumet Park. When I do see Bonaparte's here, they're usually far out over the lake as flybys (Indiana waters). It's unfortunate that Lake Michigan doesn't get greater numbers of this species like Lake Erie and Lake Ontario.

The presence of this species is almost a requisite for finding some of the rare, small gulls. Bonaparte's do not winter on Lake Michigan.

Adult Bonaparte's Gull. Calumet Park, Chicago IL; 5 NOV 2011.


This contingent of BOGUs seemed perfectly comfortable around the larger gulls. In fact, they seemed to prefer the company of the American Herrings over Ring-billeds:

Who says BOGUs don't take bread?!