American Herring Gull – in the Netherlands?

Peter Adriaens

A subadult Herring Gull photographed in the Netherlands seemed very unassuming at first, but actually shows a key feature for American Herring Gull. This feature may not be what you regularly check in gulls, and is very easy to overlook…

When Leon Edelaar sent me the following pictures of a “herring gull sp.” that he had photographed at Ijmuiden, the Netherlands, on 2 February 2013, I was very hesitant to put a name to it. The pictures had been gathering dust on Leon’s hard drive, but they recently sparked his attention because he noticed a “grey mirror” on the underside of the ninth primary (see American Herring Gull: new ID feature), which made him wonder…

Herring Gull sp., subadult, Ijmuiden, The Netherlands, 2 Feb 2013 (Leon Edelaar). Note oval-shaped, blackish patch on upper tertial.

Herring Gull sp., subadult, Ijmuiden, The Netherlands, 2 Feb 2013 (Leon Edelaar). Note oval-shaped, blackish patch on upper tertial.

Herring Gull sp., subadult, Ijmuiden, The Netherlands, 2 Feb 2013 (Leon Edelaar). Another view of the blackish ‘ink spots’ on tertials, from a different angle.

Herring Gull sp., subadult, Ijmuiden, The Netherlands, 2 Feb 2013 (Leon Edelaar). Another view of the blackish ‘ink spots’ on tertials, from a different angle.

At first sight, the bird in the pictures did not strike me as very unusual. Surely, in shape and overall plumage aspect, it looked rather like any run-off-the-mill (subadult) European Herring Gull!? However, a closer look reveals a few interesting features. At rest, the bird shows quite impressive blackish and oval shaped ‘ink spots’ on the tertials, while the rest of the plumage looks basically adult. Many European Herring Gulls show dark marks on tertials, of course, but it is quite rare to see one that looks adult except for such large, oval shaped and well-defined, black(ish) spots. That is something much more commonly seen in American Herring Gulls. Then, in flight, the bird reveals an isolated grey spot in the black pattern on underside of primaries (at least in right wing). Again, this is more common in American Herring Gull. So far so good. An interesting bird, yes, but nothing impossible for a European Herring Gull. However, then we look closely at the secondaries, and they show the most alarming feature: two small but well-defined black ‘ink spots’. Such isolated black spots on adult secondaries are not seen in European birds, and have been considered a key feature of 3rd and 4th cycle American Herring Gull ever since the identification paper by Mullarney and Lonergan (2004).

Herring Gull sp., subadult, Ijmuiden, The Netherlands, 2 Feb 2013 (Leon Edelaar). Black ‘ink spots’ on adult-like secondaries (here indicated by black arrows), and “grey mirror” on underside of P9 (white arrow).

Herring Gull sp., subadult, Ijmuiden, The Netherlands, 2 Feb 2013 (Leon Edelaar). Black ‘ink spots’ on adult-like secondaries (here indicated by black arrows), and “grey mirror” on underside of P9 (white arrow).

Other characters are less helpful. The primary pattern includes a complete, black ‘W’ on P5, and black “bayonets” on P6-7 (see Adriaens & Mactavish 2004) – good for American Herring, but equally possible for European birds. The tail shows a few small, solid black spots – better perhaps for American birds, as blackish markings in the tail usually do not look very solid in subadult European Herring Gulls. The bill shape and length look ok to me for either species, as does the colour of the upperparts. I would have expected heavier brown blotching on the neck and breast for an immature American Herring Gull, but there is a lot of variation.

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Herring Gull sp., subadult, Ijmuiden, The Netherlands, 2 Feb 2013 (Leon Edelaar). The above four pictures show the primary pattern and pattern on tail.

Herring Gull sp., subadult, Ijmuiden, The Netherlands, 2 Feb 2013 (Leon Edelaar). The above four pictures show the primary pattern and pattern on tail.

So what does it all mean? It seems that, on current knowledge and for the time being, this bird should be considered an American Herring Gull, even though it is certainly not an obvious example! Here is one from North America that is similar:

http://gull-research.org/smithsonianus/smith4cy/4cyfebr012.html

The identification of such birds relies heavily on the pattern of the secondaries. There are many people closely studying and ringing gulls in the Low Countries, and it seems that such a pattern has never been documented in the local Herring Gulls.

If anyone has ever photographed such a secondary pattern in argenteus or argentatus, both Leon and me would be very interested to hear from you…

2 thoughts on “American Herring Gull – in the Netherlands?

  1. Kevin McLaughlin

    Hi Peter. Looks promising for an AHG of the northern type. Of interest are the mirrors on P9 and on P10 on a third cycle bird. This is good for a northern AHG which certainly can possess them. A third cycle southern AHG (Great Lakes) will never show a small mirror on P9 or at least not to my knowledge. A small mirror may even be lacking on P10 or at least be very hard to see on some individuals. I should add that adults,such as those that breed on Hamilton (Ontario) Harbour, can show a small P9 mirror on a minority of individuals. I was not sure if there may be too much black running up P8 for a Northern AHG but this is a third cycle gull, not an adult so that may explain it. The bill on the Dutch gull seems large and bulbous which suggests a Northern AHG as well. The few we get at the western end of Lake Ontario in winter always give the impression of having a heavy bill.

    I liked the paper you did with Bruce on AHG in Dutch Birding about ten years ago. However, I seem to have lost it from my saved website. Could you possibly give me the link for it? Thanks.

    Kevin McLaughlin.

    Reply
  2. Pingback: Adult American Herring Gulls, seen from a Dutch perspective | Gulls to the Horizon

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