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It's All in the i-Details - 50 Shades of Gull

What is the difference between a gull and a seagull?

Gulls are members of a large, widespread family of seabirds. Often known as seagulls (though no species is actually called a seagull, and many are found far from the sea), they sometimes get a bad reputation for stealing fries. Ha ha! I found this paragraph when I googled the search word “gull”. For many birdwatchers, this just about sums up their thoughts on Larus species. For those of us who label themselves as Larophiles or “gull lovers”, we are often tagged by others with raised eyebrows and a quiet suspicion of mild insanity. It’s well deserved some days. Gull identification can be exasperating. Although I find watching gulls is quite fascinating, I am far from expert, so this blog will just touch on my methods of gulling. In other words, how do I search a flock to pick out some obvious species?

To get started in London, one should head to the dump. The landfill is full of delicious goodies for gulls as well as other scavenger birds. They congregate there in the hundreds. If an eagle makes a flyby, you can see a busy slurry of gulls on the wing, circling the fields adjacent to the landfill and above the active dump site. Cross your fingers that they will settle down in a nearby field. If possible, bring a spotting scope and/or a camera because it is most helpful to take your images home and study them on the screen with a field guide. I have even shot blindly as a stream of gulls flew overhead towards the field and ended up with surprise documentation of one species that I had missed with binoculars. It was an Iceland Gull! Take care to park well over to the side of the road on a gravel pull out because sanitation trucks come barrelling along at frequent intervals from Monday to Friday. The weekend is quiet for trucks but also quiet for gulls since refuse isn’t being added and pushed around by bulldozers.

I find the location of our local gull magnet site is challenging because on many days, the gulls are distant and on private property. I actually got hooked on gulls out in B.C.’s southern interior, where they lined up on Lake Okanagan beaches and were accessible and photographable and learnable. In Ontario, there are better locations than the London landfill, but even at a distance, you can zone in on colour variation within the flock.

For an experienced gull watcher, and on a good viewing day, it’s possible to check off six gull species here in the winter. (I only include the white-headed group since the black-hooded species like Bonaparte’s aren’t around now.) A variety of different ages will be present since it takes three to four years for birds to reach maturity, depending on size, so you will see all kinds of brownish toned immature birds. In winter, gulls also tend to have a more streaked, smudgy or “dirty” looking appearance compared to the clean-headed gulls in summer breeding plumage. To simplify the initial search, just look for adult birds with some uniform shade of gray mantle/ upper body and skip the brownish ones.

If you are a photographer, you might be familiar with the Kodak gray scale. It is a visual grading of twenty neutral tones with white at one end and blackish on the other. In between, are eighteen shades of gray in sequence of intensity. It is used as a monochromatic reference for image production. Keep it in mind as a gull reference too, hence the title of the blog (not the movie ; ).

I start my gull scans at the far end of the scale by looking for black backs. The adult Great Black-backed Gull stands out easily in a group just because it is so strikingly dark. It’s also a beast in size and can be almost twice as big as the common Ring-billed Gull. If you are close enough to see leg colour, it should be a grayish pink. It’s eye appears small in relation to the head, giving it a beady-eyed look. Another dark gray Larus may catch your eye, but its mantle is a hint lighter than the Great Black-backed. It’s called a Lesser Black-backed Gull. The gray is more of a dark, slate colour than black. This species is closer in size to the hordes of Herring Gulls present, in fact, even a tad smaller, and usually shows much more head streaking than its large, dark relative. Look for yellow legs as a diagnostic too. Up close, the red dot/splotch on the lower mandible can be pronounced and almost looks like a smear of red lipstick. It’s less common at the landfill than the Great Black-backed.

Now switch the search to the other end of the spectrum and look for ghostly pale gray mantles. Like gull snowflakes? When gulls are resting in a field, you’ll see that many, many of them have black wing tip extensions beyond their gray mantle. There are two species, however, that show white primaries (wing tips) and this field mark is visible when they are at rest or standing. Match the soft gray mantle with white wing tips and you may have either a Glaucous Gull or Iceland Gull. The white wing tips can also be seen on flying birds, but harsh lighting conditions can fool the eye making dark tips appear white at some angles. So, a gull at rest is a better model for study.

Of the pale species, Iceland Gulls are smaller than Glaucous and have a more petite, rounded head “like a tennis ball”, is how I used to remember it. As juveniles, Glaucous and Iceland Gulls are the lightest birds on the field. Light buffy scalloping covers a completely chalky-white body. Not even a hint of gray mantle. Glaucous juveniles are sometimes the easiest birds to ID because they are so big and contrasty in a shoulder to shoulder line-up with gray Herring Gulls. Also note that they have a two-toned pink bill capped with a sharp black tip and a beady eye. If present, you’ve got a species to add to your list. The bill on the frosty juvenile Iceland Gull is small and black. Be careful when looking at only one field mark, because first winter Ring-billed Gulls also have a pink bill with dark tip. The rest of its body is multi-patterned gray with black wingtips though.

After an hour of gulling, your eyes can feel “fried” from staring so intently through layers of glass. If you haven’t burned out yet, go back and revisit the abundant, common species. Adult Herring Gulls and Ring-bills are the mid-toned gray backs with black primaries. Typical Herring adults have pinkish legs and light eye colour, which can actually be seen at a distance. Ring-bills have that black line or ring crossing the middle of their yellow bill and yellow legs to match. They are runty compared to Herrings, so scan the group to inspect for obvious size differences.

Five years ago one of the species on the gull list was lumped under a different name. Thayer’s Gull became a subspecies under Iceland Gulls. Thayer’s birds didn’t disappear, they just added to the identification conundrum because they don’t have white primaries, characteristic of the group, only gray or black primaries etched with an abundance of white. With a cursory glance, you might even overlook a Thayer’s in the flock because it looks more like a Herring Gull at first. It can have blackish wing tips and pink legs. It differs from the other by having noticeably dark eyes, deeper pink legs and the small rounded head and body structure of an Iceland Gull. To verify, wait for a bird to raise its wings, and look at the underside to check for limited black on the primaries, compared to Herring.

There is a lexicon of terminology to learn if you decide to dive into the world of gull identification. Most of it relates to naming specific body parts, and feather patterns. My Sibley Field Guide has a page at the front called Bird Topography which points out locations of terms like scapulars, tertials, and gonydeal angle on the gull’s bill. It’s a good reference diagram to keep handy. In gull speak, these words are used often, along with assigning numbers 1-10 to the outer wing feathers. Since they are called primaries, they are labelled with capital letter P. P10 is the outer most feather in the wing sequence. Why so fussy about naming? Since gulls seem to be in a constant state of feather moult and changing bill colour as they age to adulthood, terminology is important. It helps fine tune species ID and a bird’s age, especially immature birds. The amount of white in black primary feathers is a routine point of discussion amongst gullers too. A quick field mark I look for on flyover gulls, is a P10 “mirror”. That’s a white circle embedded in the black tip of the outermost primary. It tells me that the bird is most likely an adult Herring Gull. I just discovered reading online yesterday that they also have “pseudo-mirrors” on the underwing. Good Grief! I don’t want to know.

Before signing off on this long rambling, I’d like to mention that gulls are famous for cross-breeding, begetting gull hybrids. So the bird you see loafing out on the snowy field may be the love child between a Great Black-back and a Herring, or Glaucous and Herring...I guess they aren’t always picky. As if there weren’t enough ID challenges to face! The phrase “typical gull” may be an oxymoron.

Gulling is an exercise in gathering evidence. Collect data on mantle colour, leg colour, eye colour, relative size to nearby gulls, head shape, and if possible get a photo. Especially one with an open wing to see the feather pattern on the tail and upper side. Put all the puzzle pieces together to make a tentative identification. Buy a field guide specific to gulls to help make sense of your data. There is a helpful Facebook Group called North American Gulls which I joined awhile back and have learned that compared to an "elite cohort", my gull skills are embarrassing and limited. It is highly educational however, to follow the posts and get familiar with gull terminology and what field marks to look for. Gulls are like the Sudoku of the bird world. I hope you like puzzles.

**Photos from top

- frosty Juvenile Iceland Gull in front of a Herring Gull,

- Scene from a field near London landfill - Note different mantle colour of Lesser Black- backed Gull (under arrow) compared to adult Great Black-backs

- Great Black-back

- Lesser Black-back

- adult Glaucous, note white primaries

- Herring Gull in flight, note pale eye

- adult Ring-billed Gull with yellow banded bill

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