Mersey Birders
Birding the North West
A Beginners Guide To Gull Identification
The Basics
Gull Topography
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The shade of grey across the back and upper wings of gulls can be one of the main identification features for that species, however, due to different lighting in field conditions, it may be one of the least useful. This grey colour, often with a bluish, flat grey, or brownish hue, depending on the species, may appear lighter or darker depending on the angle of the sun or the angle of the bird. The grey often appears darker on birds seen from the rear, lighter (and more blue) when seen from the front.
Direct sunlight can make birds appear either darker or very pale. The best viewing conditions occur when birds can be compared side by side, facing the same direction, preferably on an overcast day that eliminates sharp shadows. The following chart may give the misleading impression that birds farther down on the list will always appear darker than birds higher up. In fact, many of the shades are so close that those within 0.3 (on the Munsell scale used) of each other will appear extremely close in colour, often indistinguishable to the human eye. Thus, the mantle shade of grey is an excellent I.D. pointer when comparing species that are quite different from each other, but of limited use when comparing birds with similar shades of grey. It should also be noted that variability is most common among those species with subspecies that are most defined by mantle shade. For example, Lesser Black-backed Gulls, especially graellsii and intermedius, are probably the most variable.
Ads Yellow-legged Gull in bright sunlight and adw Lesser Black-backed Gull (intermedius) in flat light.
Ads Herring Gull in dull light and Adw Lesser Black-backed Gull (graellsii) in good light.
MUNSELL VALUE (10=white; 1=black)
(colours here are approximate; not exact)
| 7.5 7.0 |
|
Glaucous Iceland |
| 6.5 6.0 |
|
|
No2
| 5.5 5.0 |
|
Thayer's; Caspian (cachinanns) Common (canus) Yellow-legged (michahellis) Glaucous-winged Mew; Common (henei) Herring (argentatus); California; Kamchatka Vega (vegae) |
No3
| 4.5 4.0 |
|
Mongolian (mongolicus) Vega (vegae) Yellow-legged (atlantis) Steppe (barabensis) Armenian (armenicus) Heuglin's (heuglini) Western (occidentalis) Heuglin's (taimyrensis) |
No4
| 3.5 3.0 |
|
Black-tailed |
No5
| 2.5 2.0 |
|
Lesser Black-backed (intermedius) Great Black-backed; Kelp Baltic (fuscus) |
No6
The same problem arises when you are viewing photographs of gulls, the angle of the bird to the photographer, the light, the contrast settings on the camera, and other factors make identifying gulls quite tricky indeed, and caution should always be taken with certain birds, not everything can or should be identified to a species for the sake of it.
The above sequence of shots of an Adw Yellow-legged Gull, were taken with the same camera settings with the bird moving only 20yds in the 5mins of photographing, the light went from slightly cloudy, to bright sunshine and back to completely overcast, and can illustrate how the birds upperparts can look so different under variable lighting conditions.
Ageing and different moult timings of Gulls
Gulls vary in how long it takes them to reach full maturity, and show several plumage states before completing full adult, for instance the smaller gulls like Black-headed Gull take only 2 years, from hatching stage (juvenile) in June/July, they start off with a warm brown sometimes ginger colour on head, breast sides and upperparts, the wing pattern has brown on the carpal (shoulder) with a black trailing edge to the inner wing, white primary coverts with variable dark streaks, the tail is mostly white with a broad black band. They moult into first winter (1stw) from August-April, the bare parts are a dull orange and still show the juvenile pattern on wings and tail.
From April to August they moult into first summer (1sts), some gain a full but dull brown hood, and still show signs of immaturity, like a tail band which should show new white feathers from the centre beginning to appear.
Adult plumage is acquired from March-August, the upperparts are pale grey, the primaries show a white wedge to the outer wing with black tips making a trailing edge to the wing, the hood although regarded as black is actually a dark chocolate colour, with white eyelids, the bill is a marroon red with a dark mark near tip, the legs are similar in colour.
The moult to winter plumage happens from August-March, the head loses the hood and has a reduced black spot behind the eye, sometimes forming a small band over the head to join the other side, a grey wash on the hindneck appears, some birds can have a pink wash on the breast, the bill and leg colour go to a more orange-red colour.
There are birds that can be identified as second winter birds (2ndw), by showing dark markings on the tertials, and less obvious white tips to primaries, but most will be unidentifiable to adults.
Other small 2 year birds are as follows:
Black-headed Gull (larus ridibundus)
Brown-headed Gull (larus brunnicephalus)
Grey-headed Gull (larus cirrocephalus)
Slender-billed Gull (larus genei) Sometimes a 3 year Gull.
Bonaparte's Gull (larus Philadelphia)
Saunder's Gull (larus saundersi)
Franklin's Gull (larus pipixcan) Sometimes a 3 year Gull.
Sabine's Gull (larus sabini)
Ivory Gull (pagophila eburnea)
Ross's Gull (rhodostethia rosea)
The medium sized gulls take 3 years to reach maturity, birds like the Mediterranean Gull have a distinct second year plumage, although the third year plumage is not always apparent, in just showing narrow dark markings along the outer webs of the outer primaries.
Other three year Gulls include:
Mediterranean Gull (larus melanocephalus)
Relict Gull (larus relictus)
Laughing Gull (larus atricilla)
Little Gull (larus minutus)
Black-legged Kittiwake (rissa tridactyla)
Great Black-headed Gull (Pallas's Gull) (larus ichthyaetus) sometimes a 4year Gull.
Heuglin's Gull (larus heuglini)
Baltic Gull (larus fuscus fuscus)
Yellow-footed Gull (Larus livens)
Ring-billed Gull (larus delawarensis)
Common Gull (larus canus)(Mew Gull)(larus brachyrhynchus) Kamchatka Gull(larus kamtschatshensis) (larus canus henei)
Sooty Gull (larus hemprichii)
White-eyed Gull (larus leucophthalmus)
Heerman's Gull (larus heermanni)
The large Gulls have the longest time to reach full adult, these include birds like Herring Gulls, they have obvious third and fourth year plumages, they can show signs of immaturity in the wing coverts and on bill, lacking white tips to primaries, or mirrors, markings on tertials and on tail, all pointing to that age group.
Other large Gulls that take four years to reach adult are as follows:
Herring Gull (larus argenteus) Scandinavian Herring Gull (larus argentatus)
Yellow-legged Gull (larus michahellis) Azorean Yellow-legged Gull (larus michahellis atlantis)
Caspian Gull (larus cachinnans cachinnans) Mongolian Gull (larus cachinnans mongolicus) Steppe Gull (larus cachinnans barabensis)
Great Black-backed Gull (larus marinus)
Lesser Black-backed Gull (larus fuscus graellsii) (larus fuscus intermedius)
Vega Gull (larus vegae)
Black-tailed Gull (larus crassirostis)
Armenian Gull (larus armenicus)
Kelp Gull (larus dominicanus)
Slaty-backed Gull (larus schistisagus)
Western Gull (larus occidentalis)
Yellow-footed Gull (larus livens)
Glaucous Gull (larus hyberboreus)
Iceland Gull (larus glaucoides)
Kumlien's Gull (larus kumlieni)
Thayer's Gull (larus thayeri)
Californian Gull (larus californicus)
American Herring Gull (larus smithsonianus)
Age sequince Example of Herring Gull (larus argenteus)
Juvenile
Juv Herring Gull Aug07
Note the crisp scalloped upperparts, all black bill, and overall brown plumage, typical of most species. The notched tertials seperate this from the very similar Lesser Black-backed Gull at this age, which just have pale edges or tips.
FIRST WINTER/SUMMER
First winter/summer Herring Gull Feb08
Gulls typically moult from juvenile to first summer beginning in the winter of their first year, when they are less than half a year old. (Note there is no such thing as a first winter plumage that is different from juvenile or first summer plumage.) The only real change here from the juvenile above is the back and scapulars have been replaced by feathers that have bits of "adult grey" in them. Note that the wing coverts are still the juvenile feathers, but appear more worn and faded brown now. The bill has also acquired its typical first year look. On all first year gulls, the tail will have some variation of dark and white with dark barring.
Second Winter
second winter Herring Gull Feb08
Now the bird has mostly adult grey back and scapulars, with some bits of grey among the brown wing coverts as well. The wavy marbling on the greater coverts and tertials is typical in second year plumage of four-year gulls. The eyes and legs may or may not resemble the adult colour. The bill colour is highly variable. The tail will often have substantial black areas with variable marbling and white areas at the base.
Third Winter
3rdw Herring Gull 5th March 08
Now the bird is starting to look more or less like an adult, except it still has some substantial black in the bill, some flecks of brown on the wings, probably an incomplete primary pattern (not visible), and a mostly white tail with a variable and often broken tail band (not visible).
Fourth Winter/Adult Winter
4thw Herring Gull 5th March 08
Most adult species are streaky-headed in winter, all white in summer. Many species will show some black on the bill next to the red gonydeal spot in the winter only. The legs and bill often become brighter in the summer. The tail will be all white. This bird looks like an adult but has a small black mark behind the red gonys spot.
Size and Structure
When looking through groups of gulls, one thing that needs pointing out is there is a considerable size difference in male and female birds as well as in different species, so when faced with a large adult Herring Gull next to a smaller bird, you can assume you are looking at a male bird next to a female, or possibly if the bird looks darker on the upperparts but still looks like a Herring Gull, this may well be the Scandinavian Herring Gull (larus argentatus) which is the nominate race of Herring Gull, birds from further east are darker with more white in the primaries.
The other possibility to watch out for are, smaller than normal birds, sometimes birds dont develop properly at the juvenile stage due to either a lack of food or an abnormality in the birds genes, thus the bird can appear smaller than it should normally be.
When faced with a strange bird, try to look at nearby birds for a size comparison, and try and match the birds structure with that of another, and if your bird matches both the structure and mantle colouration, then the identification could be completed, remember gulls are incredibly varied in their plumages, with some birds acquiring full summer in the middle of winter, or seem to be stuck in a mix of immature plumage, possibly due to an illness, birds can delay their moult or advance it just to make things even more complicated.
Hybrids
The problem arises when a bird you are watching seems to have characteristics of two species, for instance, a bird that looks structually like a Herring Gull but has a much darker colouration on the upperparts, with yellow legs, and is clearly not a Yellow-legged Gull by the bluish tinge, showing more black in wing, a more rounded head and more heavy head streaking, will probably be a Herring X Lesser Black-backed Gull, and can always catch out the unwary.
There are a vast amount of hybrid pairings amongst Gulls and almost any combination is possible (according to size of gull species), birds that turn up in Britain regularly are Glaucous X Herring Gull, Herring X Lesser Black-backed Gull, Caspian X Herring Gull, Lesser Black-backed X Yellow-legged Gull, graellsii X intermedious Lesser Black-backed Gulls, Mediterranean X Black-headed Gull and possible Ring-billed X Common Gull.
This bird is probably a Hybrid Herring X Lesser Black-backed Gull, it had pink legs, and structure of Herring Gull with slightly darker upperparts with a bluish tinge, P10 was more like a mirror, and a smaller one on P9, with pale grey inner webs before the black tip. A small black bar on P5 similar to a Yellow-legged Gull was seen and long white tongues on P4-6.
This bird is a probable Glaucous X Herring Gull, the large structure of Glaucous Gull, along with long thick pink based bill with black tip, the mix of Herring was evident with the slightly darker primaries and a tail band, with a paler secondry bar, the underwing was very pale and very Glaucous Gull like.
Leucistic or Albinistic Gulls
From time to time, you may come across a bird that looks somewhat like an Iceland or Glaucous Gull, but doesn't seem quite right, this may be an Albino or Leucistic Herring or Lesser Black-backed Gull, which are the commonly observed species that have this plumage abnormality.
Leucistic birds are regularly recorded with pale washed out wings, or upperparts lacking the dark pigmentation, and can thus be misidentified as Glaucous or Iceland Gulls, but the true species usually shines through in the size and structure, wing and bill length, traces of dark in the wings and tail and usually the colour of the bill will be unchanged.
Albino birds are similar, these are usually totally all white and may have paler washed out bare parts i.e, legs and bill colouration.Most species of bird can have these abnormalities and there are a large selection of gull species that have been observed with this problem.
Partial Albino Black-headed Gull, showing all white plumage except the primaries and the bill and eye colour is normal.
Adult Leucistic Herring Gull with completly white upperparts, with a brown wash on primaries, the bare parts, like the bill and legs are normal.
Gull Wingtip Patterns
The following photos are of Gull wingtip patterns from museum specimens mainly from North America, which are helpful in identifying the more difficult large gulls, like American Herring Gull compared to Argenteus/Argentatus Herring Gulls from Europe,and the range of different wingtip patterns that are available.
Black-headed Gull (larus ridibundus)
Adult Black-headed Gull upperwing
Adult Black-headed Gull underwing
The white primaries on the outerwing from p10-p7, with the black tips continuing to p5 with a small mark on p4, but on the underwing, the white is only prominant on p10 and reduced on p9 + 8, and shows more black.
1stw Black-headed Gull upperwing
Compared to Adult Black-headed Gull, the 1stw has more black on the leading edge of the primaries and secondries, and brown/black in the mid wing on the median coverts and tertials, with brown streaking on the greater coverts and a more prominant black edge to p10 and 9-8.
Bonaparte's Gull (larus philadelphia)
Adult Bonaparte's Gull upperwing
Adult Bonaparte's Gull underwing
Compared to Adult Black-headed Gull the black in the wing is restricted to the primary tips only, and go from p10-p4 with a hint on p3, the underwing is mostly all white on the primaries with again just black tips to the leading edge of the wing.
Adult Black-headed Gull Adult Bonaparte's Gull
Adult Black-headed Gull Adult Bonaparte's Gull
1stw Bonaparte's Gull upperwing
Little Gull (larus minutus)
1sts Little Gull in heavy wear and moult upperwing
1sts Little Gull underwing
Sabine's Gull (larus sabini)
Juvenile Sabine's Gull upperwing
Juvenilw Sabine's Gull underwing
The distinctive white triangle formed by the white secondries, the inner primaries and the greater coverts make this a diagnostic feature for identifying this from imm Little Gull or Kittiwake which have a similar pattern to the wing.
Kittiwake (rissa tridactyla)
1sts Kittiwake upperwing
Adult Kittiwake moulting upperwing
Adult Kittiwake moulting underwing
Franklin's Gull (larus pipixcan)
Adult Franklin's Gull upperwing
Adult Franklin's Gull underwing
Laughing Gull (larus atricilla)
Adult Laughing Gull upperwing
Adult Laughing Gull underwing
2nds Laughing Gull upperwing
2nds Laughing Gull underwing
Adult Franklin's Gull Adult Laughing Gull
Franklin's Gull shows more white in the primaries with reduced black, compared to Laughing Gull which has all black primaries on p10-8 with white tips, a narrow white secondry bar and a much darker upperwing.
Mew Gull (larus brachyrhynchus) (North American)
Adult Mew Gull upperwing
Adult Mew Gull underwing
1sts Mew Gull upperwing
1st Mew Gull underwing
Ring-billed Gull (larus delawarensis)
2ndw Ring-billed Gull upperwing
2ndw Ring-billed Gull underwing
1sts Ring-billed Gull upperwing
1st Ring-billed Gull underwing
California Gull (larus californicus)
Adult California Gull upperwing
Adult California Gull underwing
Large white p10 with a mirror on p9 and black restricted to p10-p6 and band on p5.
2ndw California Gull upperwing
2ndw California underwing
American Herring Gull (larus smithsonianus)
Adult American Herring Gull upperwing
Adult American Herring Gull underwing
Adult American Herring Gull upperwing
Adult American Herring Gull underwing
In the first adult upperwing there is a large mirror on p10 with a smaller one on p9, a grey tongue on p9-p6 and a band on p5, but on adult no2 it has only one mirror on p10 and the grey tongues on p8-6 and band on p5.
1sts American Herring Gull upperwing
1sts American Herring Gull underwing
Adult American Herring Gull upperwing
Adult American Herring Gull underwing
Thayer's Gull (larus thayeri)
Adult Thayer's Gull upperwing
Adult Thayer's Gull underwing
Adult Thayer's Gull upperwing
Adult Thayer's Gull underwing
Adult Thayer's Gull upperwing
Adult Thayer's Gull upperwing
Adult Thayer's Gull underwing
Adult Thayer's Gull upperwing
Adult Thayer's Gull underwing
The variation in Thayer's Gull wingtip patterns, with the darkest winged at the bottom.
Juvenile Thayer's Gull upperwing
Juvenile Thayer's Gull underwing
1stw Thayer's Gull upperwing
1stw Thayer's Gull underwing
Glaucous Gull (larus hyperboreus)
Juvenile Glaucous Gull upperwing
Juvenile Glaucous Gull underwing
Possible American Herring Gull X Glaucous-winged Gull
American Herring X Glaucous-winged Gull Hybrid upperwing
American Herring X Glaucous-winged Gull Hybrid upperwing
American Herring X Glaucous-winged Gull Hybrid underwing
American Herring X Glaucous-winged Gull Hybrid upperwing
American Herring X Glaucous-winged Gull Hybrid underwing
Glaucous-winged Gull (larus glaucescens)
Adult Glaucous-winged Gull upperwing
Adult Glaucous-winged Gull underwing
Adult Glaucous-winged Gull upperwing
Adult Glaucous-winged Gull underwing
Juvenile Glaucous-winged Gull upperwing
Juvenile Glaucous-winged Gull underwing
2nds-3rdw Glaucous-winged Gull upperwing
2nds-3rdw Glaucous-winged Gull underwing
Glaucous-winged Gull X Western Gull Hybrids
Juvenile Glaucous-winged X Western Hybrid upperwing
Juvenile Glaucous-winged X Western Hybrid underwing
Juvenile Glaucous-winged X Western Hybrid upperwing
Juvenile Glaucous-winged X Western Hybrid underwing
Adult Glaucous-winged Gull X Western Hybrid upperwing
Adult Glaucous-winged Gull X Western Hybrid underwing
Adult Glaucous-winged Gull X Western Hybrid upperwing
Adult Glaucous-winged Gull X Western Hybrid underwing
Western Gull (larus occidentalis)
Adult Western Gull in moult upperwing
Adult Western Gull in moult underwing
Lesser Black-backed Gull (larus fuscus graellsii)
Adult Lesser Black-backed Gull upperwing
Adult Lesser Black-backed Gull underwing
Great Black-backed Gull (larus marinus)
3rds in heavy wear and moult Great Black-backed Gull upperwing
3rds in heavy wear and moult Great Black-backed Gull underwing
Juvenile Great Black-backed Gull upperwing
Juvenile Great Black-backed Gull underwing
Yellow-footed Gull (larus livens)
Adult in moult Yellow-footed Gull upperwing
Adult in moult Yellow-footed Gull underwing
Heerman's Gull (larus heermani)
Adult in moult Heerman's Gull upperwing
Adult in moult Heerman's Gull underwing
Juvenile Heerman's Gull upperwing
Juvenile Heerman's Gull underwing
Recommended Reading
- Gulls of
- Gulls, a guide to identification. P.J. Grant. 1982. ISBN 0-12-295640-0
- Identification of Yellow-legged Gulls in
- Identification of juvenile and first-winter Thayer's Gull. M.Garner and A.McGeehan Birding World Vol 11 No3 94-101.
- The Adult Thayer's Gull in Donegal. A.McGeehan and R.Millington Birding World Vol 11 No3 102-108.
- American Herring Gull: In another age. R.Millington and M.Garner Birding World Vol 11 No3 109-112.
- Yellow-legged Gulls and yellow-legged Herring Gulls in the Baltic. Lars Jonsson. Alula 3/1998: 74-100
- Caspian Gull Gallery. Theo Bakker, Rudy Offereins and Rik Winters. Birding World 13:2/2000 60-74.
- Winter Gulls Gallery.R.Millington and M.Garner Birding World Vol 12 No2 62-68.
- Is it possible to identify Baltic and Heuglin's Gulls?C.Gibbons Birding Scotland 2004 view here
- The primary moult of the Lesser black-backed Gull L.Fuscus P.Stewart The Severn Estuary Gull Group 2006 view here
- Identification update: Moult variability in 3rd cal YR Lesser Black-backed Gulls. M. Mousse, T.Mousse, B.J.Altenberg 2005 view here
- Variably plumage Icelandic herring Gulls: R.Snell Auk 110 (2) 410-413 1993 view here
- Intergradation between the herring Gull larus argentatus and the sothern Herring Gull larus cachinnans in European Russia: E.N.Panov, D.G.Monzikov, Russian Zoology Vol 3 no1 1999 129-141. view here
- Origins and identification of Kelp X Herring gull hybrids: D.Dittmann, S.Cardiff, Birding June 2005 view here
- Kelp Gull at Banc d'Arguin- a new Western Palearctic bird, O.Pineau,Y.Kayser,M.Sall, A.Gueye,H.Hafner, Birding World Vol 14 No3 March 2001, p110-111.
- Identification of Kelp Gull, F.Jiguet,A.Jaramillo,I.Sinclair, Birding World Vol 14 No3 March 2001, P112-125.
- Identification of Atlantic Yellow-legged Gulls, Philippe Dubois, Birding World Vol 14 No7 July 2001, P293-304.
- Identification and ageing of Audouin's Gulls, J.King, H.Shirihai, Birding World Vol 9 No2 February 1996, P52-61.
- Great Black-headed Gulls in Europe, Zoltan Ecsedi, Birding World Vol 9 No8 August 1996, p303-312.
- The Thayer's Gull in Belfast, A.McGeehan, M.Garner, Birding World Vol 10 No3 March 1997, P93-100.
- Dump Gulls, A.McGeehan, M.Garner, Birding World Vol 10 No3 March 1997,p101-102.
- Thayer's Gull, Letter in Birding World Vol10 No7, July 1997, P270-274.
- Putative Glaucous X Herring Gulls, Letter Birding World Vol10 No7, July 1997, P275-277.
- Baltic Lesser Black-backed Gull Larus Fuscus Fuscus- Moult, Ageing and Identification, Lars Jonsson Birding World Vol 11 No8 August 1998, P295-317.
- Another Thayer's Gull in Ireland Pat Lonergan, Birding World Vol 12 No1 January 1999, P38-39.
- Gulls in Japan, J.King, G.Carey, Birding World Vol 13 No4 April 2000, P160-163.
- Identification of 1stw Kumlien's Gull and the Whitby Gull, M.Garner, Y.Kolbeinsson, B.Mactavish, Birding World Vol 13 No3 March 2000, P116-119.
- The Thayer's Gull in Norway A.Tore Mjos, M.Garner, Birding World Vol 13 No1 january 2000, P10-11.
- Caspian Gull Identification Revisited, G.Neubauer, R.Millington, Birding World Vol 13 No11 November 2000, P462-465.
- The American Herring Gulls in County Cork, John Diggin, Birding World Vol 14 No2, February 2001, P62-65.
- The Juvenile Caspian Gull in Suffolk, Brian Small, Birding World Vol 14 No9 September 2001, P385-387.
- Winter Gulls in Ireland, Chris Batty, Birding World Vol 15 No2, February 2002, P72-73.
- Three American Herring Gulls on the Isles of Scilly, Bob Flood, Birding World, Vol 15 No3 March 2002, P106-110.
- A Cape Gull in Paris- A New European Bird, F.Jiguet, P.Defos Du Rau, Birding World Vol 17 No2 February 2004, P62-70.
- Winter Gull Gallery, C.Batty, T.Lowe, R.Millington, Birding World Vol 16 No3 March 2003, P114-125.