There's no such thing as a Seagull! A Gull Identification Guide

This week I thought I would take a look at some birds I'm sure we are all familiar with, Gulls. Whilst Loch Ryan is on the coast, and therefore gets a lot of gulls, they have become so widespread that even living out in the country or in a city poses no barrier to seeing them (as a resident of Glasgow for several years, I can attest that they get plenty of Gull species). For a lot of us though we may often just dismiss them, "oh its just a seagull", or for others it can be a genuine struggle to separate the many species. Hopefully I'll be able to pass on some tips to get you confident in your Gulls and encourage you to give them more than a passing glance, after all you never know what you might see. 

On Loch Ryan we have recorded 17 different species of Gulls, however I'd like to focus on 6 of our more common species and then perhaps discuss some rarities for each section. For the most part I will be discussing these species in their adult plumage's, since this is the most distinctive and easiest to identify them by (and I profess, even I struggle when it comes to different age juveniles), I will however mention moults and aging birds at the end. 

Sketch of various Gulls and Seabirds

Starting with the smaller Gulls, we will consider Black-Head Gulls, Common Gulls and Kittiwakes. The first of these is a little bit of a misnomer, since its head is in fact dark brown and this is only during its summer plumage's. During winter I identify them by their smaller size and distinctive red bill. Common Gulls by contrast have yellow bills and whilst slightly larger, are still noticeably smaller than Herring Gulls and so can be separated based on their smaller, more rounded heads and dark eyes. Unlike the rest of these gulls Kittiwakes are more adapted to seagoing and so are rarely seen far from coastal areas. Initially they do appear to be very similar to Common Gulls, however they have distinctive pure black wing tips, whereas a Common Gull has patches of white dispersed among the black. And on the subject of wing tips, its worth mentioning a semi-rarity in Mediterranean Gulls. These look very much like, and are often found among groups of Black-Headed Gulls. Whereas the Black-Headed Gulls have black markings on the wing tips and tail, Mediterranean Gull's are pure white and so a quick glance at the rear will help identify them. 

Moving into the larger gulls, I want to look at Herring Gulls and Lesser and Great Black-Backed Gulls. Herring Gulls are our most prolific gull, indeed they're widespread across the country and are probably the one species we all know, they are the stereotypical "gull" to the public. If you see a large gull with a yellow bill and grey back, then the safe bet is its a Herring Gull. Lesser Black-Backed Gulls also fit this description, however have noticeably much darker grey backs. If like me, you see a solitary bird, then you could well ask "is that grey actually dark enough?" however a comparison with a Herring Gull should show the distinctive difference in shade. Great Black-Backed Gulls are perhaps the easiest to identify, for they are truly massive amongst these other gulls and rather than grey their back is unmistakably black. They also have pink legs compared to the yellow of Lesser Black-Backed Gulls.

Lesser Black-Backed Gull (left) with a Herring Gull (right)

It is when looking at some rarer species that the difficulty arises, as many species are extremely similar to the Herring Gull (and so can easily go unnoticed). For us, these are the rare Yellow-Legged Gulls. Yellow-Legged Gulls are (to my eyes at least) identical to Herring Gulls, other than their named characteristic. But wait, if looking like Herring Gulls wasn't enough, Herring Gulls can also have yellow legs (a Baltic variation that have been recorded locally). And to top it all off, another species, the Caspian Gull, also fits under this exact description. Really there is no one distinctive feature that separates all of these species, it comes down a good understanding of the many subtle differences and a practiced eye (so neither of mine!). Its not all bad news though, if you do spot a gull with yellow legs, try to get a picture, if possible with another gull in for comparison. A lot of the differences become more obvious with a static image and whilst its easy convince yourself of something in the field, a picture provides hard evidence off which to base your identification.

And finally, I have to mention moults. All of these aforementioned gulls have been in their adult plumage, but many species need 2, 3 or even 5 years to reach adulthood. This can lead to a huge variety of juvenile plumage's which between similar sized species can lead to even more confusion. Much like the rarities, this really is where you need an experienced eye to decipher the mix of streaks, patches and many shades of grey. Fortunately, Loch Ryan is a great place to practice and in the winter we get all stages of immature's for the common species I've mentioned. 

The moult of gulls - taken from Collins Bird Guide

And that about wraps it up for Gulls. Despite their national commonality, there is a complexity to gulls that can stump even the most experienced birder. As for Seagulls, the Latin name for the Great Black-Backed Gull is Larus marinus, which translated and taken together means sea gull. So maybe seagulls do exist after all...

 (All pictures belong to Stephen Grover, please ask for permission if you wish to use them)