Some Thoughts on the Separation of "white-winged" Kumlien's Iceland Gull from Nominate g.glaucoides Iceland Gull

This is an article I've been threatening to write for some time. So now finally, at 12:01 tonight I decided to sit down get to work. Before I get into any discussion I should advise that I've never been to Greenland or Iceland and have no real life experience with g.glaucoides in their true range.So, feel free to take what I say with a grain of salt, should you decide to keep reading at all.Having said that I've seen a hell of a lot of Kumlien's Iceland Gulls, and have a good feeling for the limits of variation within that subspecies, if you want to call it that. Over the years, I have looked at every photo of g.glaucoides I could get my hands on, and and photographed a number of individuals in Newfoundland, some of which I will share in this article.

Throughout the course of this article I will discuss the variation in Kumlien's Iceland Gull and compare that to (what I think of) g.Glaucoides. I will discuss criteria for separating these two subspecies (based on a Newfoundland, or perhaps just my, perspective). I will limit my discussion to adult birds only,since I have not seen any reliable way of separating juveniles and fist winter birds. As birds get into their second, and especially third winter, they become easier to separate but as I said, I will concentrate on adult birds. I will give particular attention to those Kumlien's Gulls that could present a possible caveat for those wishing to identify g.glaucoides. Alternately, this may be of use to European birders, who endeavor to identify out of range Kumlien's Gulls.

Newfoundland seems to host the lion share of the winter population of Kumlien's Gulls.While they are very well represented throughout the Canadian Maritimes,with some into the mid west and Great Lakes and down the eastern seaboard into New England, I doubt there is anywhere else on earth one could witness the numbers and diversity of Kumlien's Gulls that we see in St.John's, Newfoundland in winter. This combined with the fact that I just don't have much else to do in winter has afforded me the opportunity to gain an intimate knowledge of Kumlien's Gulls over the last 10-12 years.

Over that time I've witnessed a number of characters that seem to separate Kumlien's from g.glaucoides. Among the more important of these are,

1) mantle shade- Kumliens slightly paler than smithsonianus HERG while g.glaucoides is as pale a Glaucous Gull or paler.

2) eye color- Kumliens can vary from very pale to very dark but ALWAYS has at least some dark peppering in the iris while g.glaucoides ALWAYS has a fully pale eye without dark peppering ranging pale to creamy yellow reminiscent of Glaucous Gull.( I'm open to revising this statement, if someone can provide me with conflicting evidence)

3) Primary coloration- Kumliens varies from having dark marking on as many as 6 outer primaries (though usually 4) to pure white wing tips with dark pigment restricted to the outer web of p10 (sometimes very faint) g.glaucoides never has dark markings or any kind in the wings as adult-- always pure white tips and lacking any dark marbling in the outer web of p 10.

4) structure- On average Kumlien's seem to appear larger billed,with less rounded head. Appear more menacing and bulky overall. The smallest g.glaucoides can appear very dainty with quite small, Dove-like heads.

While there may be other differences,I believe any Iceland combining all of the above characters, one way or the other, can be safely assigned to subspecies. Any Iceland Gull that appears extremely dainty, with a clear yellow eye, pure white wing tips and mantle color matching GLGU is probably, if not certainly a g.glaucoides. At times there are birds that have 3 of 4 of the above characters and are suggestive of g.glaucoides but I choose to leave these birds unidentified.




Example of g.glaucoides- like Kumlien's Gull. Structurally very reminiscent of g.glaucoides with smallish bill, rounded head, creating a dainty impression. Wings apparently pure white,lacking any dark markings. However, note mantle coloration same as surrounding Kumliens Gulls and dark eye. What does this mean??

MANTLE SHADE

Kumliens Gulls have a mantle shade just lighter than smithsonianus Herring Gull, but noticeably darker than any Glaucous Gull. In direct comparison with glaucoides Kumlien's appears at least a shade darker. See photos below.

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Presumed g.glaucoides,St.John's, Newfoundland,December. Compare to Herring Gull on left and Kumliens Gulls on right and behind. Also note similarity in Kumlien's and Herring Gull mantle shade. Note this individual shows all four key features mentioned above, pale mantle, pure, pale eye,lacking dark peppering, pure white wings. Structurally this bird was a little bulky, so probably a male.


Presumed g.glaucoides, late January, St.John's, Newfoundland. Compare with Kumlieni to the left. There is less contrast between the primaries and mantle in glaucoides then even the whitest winged kumlieni.

EYE COLOR

Eye color is among the most variable of all Kumlien's traits. However, in my experience there are limits. There seem to be a couple of potential rules among the variability.

1) While KUM iris' can appear completely dark to completely pale,there is ALWAYS at least some dark peppering in the iris.

2) In adult g.glaucoides there is NEVER a large amount of dark peppering in the iris. The adult eye color is usually a clear creamy yellow and mostly lacking the more amber and golden tones shown by pale eyed Kumlien's. From what I can see most of the time it lacks any dark spots in the iris whatsoever,but perhaps some can show a few dark specs.

Below are a series of photos displaying the range of eye color possible in Kumlien's Gull with a few g.glaucoides thrown in.














3rd winter g.glaucoides,Newfoundland,January. Note the creamy-yellow color lacking dark peppering.





Adult Glaucous Gull, Newfoundland, January. Note similarity to the g.glaucoides above.

PRIMARY COLORATION

This is actually quite straightforward. While Kumlien's Gull can pretty much range from primary patters closely matching those of Thayer's Gull to almost pure white winged as in g.glaucoides. The whitest winged Kumliens have only a very small amount of dark coloration (sometimes limited to light gray marbling) on P10.

In contrast to Kumlien's, adult g.glaucoides NEVER has any dark coloration in the primaries.

Three dark-winged Kumlien's Gull's.




White-winged Kumlien's Gulls

While the above birds would never be mistaken for g.glaucoides there are some more confusing individuals. While some Kum's have dark marking on the outer 5-6 primaries ( usually grayish) there are others that can appear completely pure, white-winged. When you find an Iceland Gull that seems to lack any dark markings in the primaries, its important to remember the other criteria that distinguish Kumlien's and g.glaucoides, such as mantle shade and eye color. Then, if possible scrutinize the wings as closely as possible looking especially for any signs of darker markings on p10,mainly on the lower 2/3rd's of the feather in the outer web. Some examples of pale winged Kumlien's below.








STRUCTURE

Structurally Kumlien's can be quite variable. In general it has a smallish billed and more round headed (less sloping forehead)appearance when compared to Herring Gull. This creates a much more gentle expression and a more overall dainty feel to the bird. Among Iceland Gulls g.glaucoides tend to have an even more dainty appearance than Kumliens, often being shorter bill and having a steeper forehead. I don't have a complete understanding of the structural variability in g.glaucoides, but the individuals I've seen in Newfoundland have all been very short-billed round headed individuals. I'm sure there is much overlap with Kumlien's so this is just an accessory feature to be used along with mantle shade, eye color and primary coloration.


g.glaucoides Iceland Gull February, Newfoundland

g.glaucoides, Iceland Gull, January Newfoundland.
g.glaucoides Iceland Gull, January, Newfoundland. Note the steep forehead and very rounded crown, along with short bill creating gentle expression.


This article is not meant to be a definitive work on the separation of these two subspecies, but rather a discussion of some of my observations here in Newfoundland. As I continue to get a better grasp on the potential variation that exists in g.glaucoides I hope to update this article.We're still learning more about these birds every day!For now I'll leave you with one last photo that serves to accentuate the extreme variation found within this species.



Two Kumlien's Gulls, February, Newfoundland. These two individuals nicely display the extreme variation in primary coloration that exists within this species. I am thrilled to be able to provide educational and entertaining content. However, these articles are very time consuming to write. If possible please considering subscribing to the blog with a very small monthly fee via the subscribe button. This will help to cover costs of website maintenance and all the other expenses that go into producing the content. Whether you subscribe or not you will still have access to all the content, the small subscription fee is just a means of showing your support. Thank you!

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2nd Winter Thayer's Gull??

Given the extreme variability we witness in Kumliens Gulls in Newfoundland, "real" Thayer's Gulls are extremely hard to pin down. I found this bird three days ago feeding at a sewage outflow with a few hundred Kumlien's Gulls. There are Herring Gulls and Greater Black-backed Gulls in the harbour but they rarely visit the sewage outflow. This bird was feeding among Iceland Gulls and feeding in a similar fashion, nervously pecking at the surface of the water. It was often in the middle of the action and aggressive. While generally the challenge here is to determine whether there is Kumlien's influence, the challenge with this bird seems to be differtiation from Herring Gull. Below I have a series of not great photos but hopefully it will be enough for those with extensive experience with Thayer's Gull. There were a few 2nd winter Kumlien's Gulls that looked very similar this bird but the wings were always paler with more extensive pale tips. As well, they tended to have a more short-billed, round headed impression in comparison to this bird, which looks to have a rather sloped forehead.

I appreciate any thoughts on the identification of this bird.

Update and FORK-TAILED FLYCATCHER!

Ok so I'm a bit late in updating here but I've been kept busy birding and working and chasing Fork-tailed Flycatchers! I'll have more to say about that later.

So the last low pressure system did bring birds with it. We weren't inundated with hordes of southern warblers and vireos but there was a noticeable arrival of warblers on the Cape Race road at the extreme south eastern tip of the Avalon Peninsula. ( see map in previous post).

There is not much vegetation in this area and nothing much to hold deciduous tree loving migrants. In fact I don't think there is a single deciduous tree or shrub on the entire 21 km road. There might be a single small Mountain Ash but it could have died. What is there is tuckamoor. I'm planning on dedicating a post soon to "birding the tuck" as we call it. This refers to birders attempting to coax passerines from scattered,dense, tangly patches of stunted conifers. It's not an easy endevour but can produce some amazing results, but again that's for another time.

So, three of us hit the Cape Race road on Oct 9 and 10th. Our efforts resulted in 8 species of warblers and two Vireo species. Highlights included, Orange-crowned Warbler (3), Prairie Warbler (5),Palm Warblers (6-8),Nashville Warbler,Pine Warbler,Yellow-breasted Chat (2) and Warbling Vireo. There were also 6+ Yellow-billed Cuckoos, a bag of Baltimore Orioles and 6-7 Dickcissels.

So overall not bad for the area. On a standard day you could bird all of the Cape Race road in October and not see any passerines other than Savannah Sparrow. There was definitely an arrival.

So that was then and this is now. News broke yesterday of a Fork-tailed Flycatcher in Renews. In fact, I broke the news after opening an email from a contact down there. As soon as I opened my email and saw an email titled "stange bird" i got excited. I opened the email and was instantly floored! I never even opened the thumbnail images, it was already obvious that the bird pictured was an adult FORK-TAILED FLYCATCHER!!

I bolted from the couch with Jen asking what, what's going on. I muttered something while getting my coat on. Fo... led ly..catcher. "what? she said. FORK-TAILED FLYCATCHER!!, where are my keys!? Then, Jen says "We have to call people". Right..and when was the bird seen. In my excitement I had forgotten everything else. All I was thinking was, I have to get to Renews, now! I looked at the message again and it was apparent that it was seen very recently. I was now bordering on frantic. Before I could go I had to do a couple of things, I had to take the dog out and make some calls. I figured I'd combine these while Jen got ready. I was outside walking up the road with the dog trying to break the news on this bird.One by one, I either left messages or gave people the news. I returned home to find Jen ready and we hit the road. I had Jen make some other calls as I was driving.

Things were going well, I was swerving in and out of traffic, passing cars under questionable circumstances until we saw something up ahead- a police car, but was it? It was the right color the right model, it had an odd antenna thingy on top and some kind of white and blue reflective tape or something across the bumper, not to mention an RNC sticker on it!! There were two people in the car and one had obviously large aviator sunglasses on. That pretty much sealed it, we were behind a police car- great!

We were thinking what a great story it would be if we got pulled over by the cops, then somehow convinced them to give us a high speed escort right to the birds location. Since this was not likely to happen, we settled in and resigned to a slower than intended drive. Well, as it turns out these cops must have had somewhere to be because they were driving well over the speed limit and I was staying right behind them.I figured, they can't give me a speeding ticket to someone who is behind then right? Well, we tailed the cops almost all the way to Renews at about 25 km\hr over the speed limit and got there in almost record time. Now all we had to do was find the bird!

We made a pass through the area where it had been seen and nothing. We spoke to the discoverer and we were informed that it was on the wires directly above where we were standing only 15 minutes before we got there! Ok, we knew it was still around, it was only a matter of time. Soon, more birders arrived and we provided them with the info and split up. I took off in the car to broaden the search. Only about 5 minutes later my phone was ringing. I answered it and heard " we've got it, right where it was last seen!". I wasted no time getting there and finally on the wires, there it was, a perfect, adult Fork-tailed Flycatcher. This is a species I had chased in Newfoundland before but had not been successful and now here it was, it felt good, a big relief. It was a Newfoundland life bird and #264 on my current year list, putting me 17 species ahead of the previous record.



5th Fork-tailed Flycatcher for Newfoundland but the first that stuck around long enough to be viewed by numbers of birders. (as of Oct 18 the bird is still around)

Will There be Birds or Won't There be Birds That is the Question!

Over the last few years I've been spending an inordinate amount of time studying weather maps and radars and then comparing those maps and radars to significant birding events in Newfoundland in an effort to better predict the types of weather patterns that lead to some of our fall outs of southern passerines. Predicting migration is no easy task in Newfoundland. Most places just wait for a cold front to pass through and they know that there will be bird movement on the back end of the low on NW winds. Actually I'm leaving a lot of stuff out there. Its not actually that easy at all but I'm not going to get into a detailed analysis of the conditions that favor bird migration just yet. I'll save that for later.

For now, I basically want to share some speculation with you all. After all, that's what birders do best- speculate. Speculate about their next year bird, the next life bird, county bird, province bird, ABA bird. You get the idea right? I'm speculating about bird migration, more appropriately reverse migration.

Now there is a term that is familiar to many birders but still completely foreign to others. Therefore, let me explain how I understand reverse migration. Lets start first by breaking down the term into its individual bits. First, lets take reverse. That should be easy enough. A common every day term. If you drive a vehicle you know it well as going backwards. This is true, for our purposes reverse will mean backwards or the opposite of what is commonly believed. Now migration. For our purposes we're only applying this to birds so lets say that migration is simply a movement of birds towards an INTENDED destination. What's important to note here is the terms movement and intended. Birds are moving and they are headed towards an intended destination.

So, now lets combine these two terms reverse and migration, as we have defined them. When we do that we can define reverse migration as "the movement of birds in a direction which is OPPOSITE to their intended or commonly believed destination." If you haven't guessed I'm feeling especially philosophical this evening. So more simply, if passerines are generally thought to undertake a North-South migration each fall,a group of passerines that have made a sudden movement south to north would be said to have undertaken a reverse migration.

Some people get all touchy over use of then term reverse migration, but most of these people are failing to apply the term comprehensively enough. Reverse migration takes in all reasons that birds might have to migrate away from their generally intended destination. Two of several reasons for reverse migration in birds, are weather and 180 degree misoriention. For example, a large flock of birds gets caught in a strong low pressure system and is swept north on SW winds. For an excellent example of this ,read this article about one of the most dramatic weather related reverse migrations ever!

Reverse Migrants in Nova Scotia

However,not all occurrences of off track birds, or reverse migrants can be explained by weather patterns. It is thought that some reverse migration in birds is due to a genetic defect that causes birds to migrate in the wrong direction by 180 degrees. Therefore, they go north when they should go south, west when they should go east etc. To my knowledge this is still somewhat theoretical but could explained some odd movement of birds. For example why are their Yellow-throated Warblers in St.John's every winter??

Anyway, lost in all of this rambling there was a point. I wanted to take a look at the weather maps over the past couple of days, compare them to the radar images of the same area and then actually get out in field to do some birding to see if any of this time spent analyzing this stuff actually pays off!

So lets start by looking at yesterday's weather map and the associated radar images for the eastern seaboard (for those who didn't know, we can see flocks of migrating birds on radar!!)



Weather Map for Oct 5- Notice the isobars running all along the NE Seaboard all the way south to North Carolina then turning NE and crossing Newfoundland

Radar Images for Eastern Seaboard for Oct 5

In watching the radar images note the large circular blobs that are growing and moving. Those are birds! Note that there are a large number of birds launching themselves out over the sea off of New York. Isn't it conceivable that some of those birds could get caught up in the south westerly flow and ride those isobars straight to Newfoundland?



Weather Map for Oct 6- Again the isobars are stacked around the eastern seaboard. This time they have moved a little father north and run basically from New York-Maine and wrap around straight to Newfoundland.

Radar Images for Eastern Seaboard for October 6

Once again we can see heavy migration all along the eastern seaboard. We also know that there is a pretty strong south westerly flow lying just off shore that is directing winds straight from New York to Newfoundland's Avalon Peninsula. Now look at those blobs on the radar. Notice how they bulge out over the coast in several places. These are birds moving out over the ocean in an effort to move south along the eastern seaboard. Once again its' possible that some could get out there and get caught up in the strong south westerly flow and engage in a reverse migration by following those south westerly winds all the way to Newfoundland

Tomorrow I'll be up well before dawn enroute to check out the migrant hot spots on the southern Avalon. There are four locations high on my list of places to check, Powles Head,Cape Pine,St.Shotts and Cape Race. See the maps below to get an idea of where these places are located.




Map showing the locations of 4 excellent migrant traps on the southern Avalon Peninsula. From left to right St.Shotts, Cape Pine, Powles Head, Cape Race



A more local view of the migrant traps. The long 16 km road that leads to Cape Race can be particularly good for holding vagrant passerines

So there you have it. This is an example of how I might prepare for a day birding. Look at the weather maps, look at the radar,choose my route, then get out there and find some birds. Like I have said before,this is not a perfect science. It is easy to see that some birds definitely got swept out over the ocean over the last two nights but will they head towards Newfoundland. If they do, will they fall out at one of my intended birding sites. Even if all of the above works out I still have to locate and identify them in vast areas! When you consider all of this is seems like a miracle that we ever find any rarities at all!

More likely it means that the number of rarities present is actually far greater than we presume, we are just lucky enough to find a very small percentage of them!


I'll try to update tomorrow or the day after to let you all know how things worked out.