Getting To Grips With Meds
Mediterranean Gulls versus Black-headed Gulls
In the past ten years, Ireland has seen a major influx of several species, among them being Little Egrets and Mediterranean Gulls. Of course, egrets are simple to identify. They are attractive small white herons with long plumes in summer. Mediterranean Gulls are different beasts altogether. For many, the thought of actually sitting down to try and identify gulls is too much like hard and challenging work. They look like Black-headed Gulls and there are too many ages to learn. However, I’ll let you into a secret…it isn’t that difficult. Of all gulls, Med Gulls (to give them their cool name) are among the easiest and the most beautiful! The other great thing about Med Gulls is that they are usually found with Black-headed Gulls so direct comparisons are easily made. The final thing about all gulls is that, unlike warblers, gulls will sit or stand around for hours and allow you to watch them and learn their plumages with ease. Gull watching is in fact one of the easiest forms of birding.
Med Gull V Black-headed Gull
So, how do you tell these two species apart? Both are very similar in size and colouration. In summer both have ‘hoods’ which, in winter, is replaced by a black spot behind the eye. However, in all plumages, Med Gulls appear slightly larger than Black-headed Gulls, have bulkier and heavier looking bodies, thicker necks and more square-shaped heads. Their bills are also thicker and heavier than Black-headed Gulls. In fact, to my eye, their bills seem too heavy and Med Gulls always to seem to hold their heads slightly downwards as if they are carrying a really heavy weight. This is of course the birds’ ‘jizz’ (their personality - sometimes referred to as the ‘general impression of size and shape’). Often the first thing you might notice is simply the bulkier shape of a Med Gull among a flock of Black-headed Gulls.
Understanding the ageing process
The next thing is to try and age the bird. However, before even trying to do this, it is important to understand the ‘ageing process’ of gulls. This all seems very complicated at first but it is relatively straightforward. All gulls take several years to reach adulthood. The large gulls such as Herring Gull, take up to five years while birds like Black-headed Gulls take three. In this article we are concentrating on Black-headed and Mediterranean Gulls so we are only looking at a three-year cycle before the birds become adults. Each year, gulls go through a feather moult and, with each moult, they change their appearance slightly. As each year passes, each moult brings them closer to adult plumage. Their bill and leg colour also changes each year. Once they reach adult plumage, there is no way to age them…a 20-year-old gull looks exactly the same as a 10-year-old! Birds are aged according to the stages of moult they are at. The different stages are as follows:
Juvenile: this is just after the bird has left the nest. It has a full set of feathers for flying but many of the upperpart and head feathers are designed for camouflage.
1st winter: this is the birds first ever winter plumage. This plumage is reached when a juvenile moults some of its body and head feathers (a partial moult) in late summer.
1st summer: It’s the birds’ first birthday…it is now one year old. This plumage is reached when the bird moults some of its body and head feathers in spring (after the birds 1st winter).
2nd winter: this is the birds’ second winter on the planet…it is now a year and a half old. This plumage is reached by a complete moult of wing, body and head feathers just after the summer (the birds 1st summer).
2nd summer: Guess what…it’s the birds 2nd birthday…its now two years old and looking more adult like. Many birds even show an adult like hood. This plumage is reached by a partial moult of head and body feathers in spring (after the birds 2nd winter).
3rd winter/adult winter: At this stage the bird is exactly the same as an adult…this is the birds third winter and is now almost fully mature (in mid-winter it will be two and half years old). Sometimes the only giveaway may be the fact that the bird’s bill isn’t as bright as a full adult. This plumage is reached by a complete moult after the summer (the birds 2nd summer).
Adult summer: reached by a partial moult of some head and body feathers in spring. The bird is now a full adult and in full breeding plumage.
Adult winter: a full winter plumaged adult bird reached by a complete moult after summer.
Of course, during the entire course of this process, birds are often in the middle of moulting so sometimes birds are referred to as being in two plumages (i.e. a bird moulting from it’s first summer plumage to its 2nd winter plumage… would be a 1st summer/2nd winter bird).
So having grasped what all the ageing terms mean, let’s look at Black-headed and Med Gulls side by side and go through the identification process.
Even at this young age, the structure of the two species is very different. Med Gull is heavier in build with a thick, heavy dark bill ( Fig1). Compare this with the juvenile Black-headed Gull ( Fig2). The Black-headed Gull appears smaller headed, with a longer neck and a slender long bill which is pale red at the base. Even the leg colour is different with the Med Gull having much darker legs than the Black-headed. This juvenile Med already has the deep- chested stand so typical of the species. Plumage-wise, juvenile Black-headed Gulls are warmer brown above, with a brown collar on the back of the neck.
Med Gulls are colder in colour tone and show a more ‘scalloped’ pattern on the upperparts with each feather having a neat pale edge. In flight, juvenile Black-headed Gulls ( Fig 3). show the classic Black-headed wing pattern with a white wedge on the forewing (the primary feathers). Even in flight, they appear slender and always show that slim bill. By comparison, juvenile Med Gulls in flight ( Fig 3a) show a blackish forewing and always appear deep-chested and heavy billed.
However, by comparison to a 1st winter Black-headed Gull ( Fig 5a ) , the black behind the eye is thicker on Med Gull, often giving them the appearance of wearing headphones. Once again, note the difference between the shape and colour of the bill as well as the leg colour.
At this stage both species begin to look totally different. They will have completely moulted all their wing feathers and body feathers. In this plumage only a few Black-headed Gulls can be aged with accuracy with some showing small amounts of brown on the wings. Med Gulls are easily aged in their 2nd winter plumage as their upperparts become very pale grey and their wing tips show a striking black and white striped (or spotted) pattern. Compare the wing pattern on the Med Gull in the foreground with the winter Black-headed Gull in the back ( Fig 9 ). Note once again the square-shaped head, the deep chest and the heavier bill on the Med Gull as well as the more reduced black spot behind the eye on the Black-headed.
By this stage, birds are now two years old. Both will show a full adult-like hood during the summer but will still show the same wing pattern as in 2nd winter plumage. At this stage, the shape and colour of the hood on both species are very obviously different. With Med Gull ( Fig 10 ), the hood is jet black and extends well down on the neck (like an executioners hood!). On Black-headed however, the hood is more reduced, stopping at the back of the crown and is browner in colour ( Fig 11). Also note that at this stage the bill of Med Gull is brighter while that of Black-headed tends to be duller.
In full summer plumage, Med Gulls are very handsome. With jet black hoods extending down the neck, bright red bills and legs, and pure white wingtips, they are unmistakeable ( Fig 20 ).
Note that the hood shape can change according to the posture of the bird.
) is more hunched so the
hood appears much reduced. However, Black-headed Gull in summer shows a
browner, smaller hood
) and, as
always, has a more slender bill, black and white wings, and always lacks
that deep-chested appearance.
winter, Mediterranean Gulls are regularly found at Gormanstown, Rogerstown,
Swords, the North Bull Island, Sandymount and at Sandycove.
Images: Eric Dempsey (www.birdsireland.com) & Paul Kelly (www.irishbirdimages.com )
Thanks also to Derek Charles.