OPLOSSING / SOLUTION MYSTERY BIRD 24



De juiste oplossing van ronde 24 is Pontische Meeuw. Alle 22 inzendingen waren onjuist. Wel werden de volgende soorten genoemd: Geelpootmeeuw (7), Amerikaanse Zilvermeeuw (7), Zilvermeeuw (6), Ringsnavelmeeuw (1) en Zwartkopmeeuw (1).

Deze 3e-winter (4e kj) Pontische Meeuw werd op 19 februari 2017 gefotografeerd door Jan Bisschop bij de Bodensee in Zwitserland.

The correct answer for round 24 is Caspian Gull. None of the 22 submitted answers were correct.

The following incorrect answers were given: Yellow-legged Gull (7), American Herring Gull (7), European Herring Gull (6), Ring-billed Gull (1), and Mediterranean Gull (1).

This picture of a third-winter (4cy) Caspian Gull was taken on February 19th, 2017 by Jan Bisschop at Lake of Constance, Switzerland.|

Notes on the identification:
After consulting with a number of gull experts it appeared that the mystery bird does not show any diagnostic features that would allow identifying it. There are at least 4 large gull species (recorded in Europe) that can show the combination of features shown by the mystery bird in their third winter. These are American Herring Gull, European Herring Gull, Yellow-legged Gull, and Caspian Gull. Armenian Gull (occurs marginally in geographical Europe), and Vega Gull (recently recorded in Ireland) are two other species that perhaps may show the combination of features of the mystery bird. Thus, this round appears to be a gamble round with 4 (or perhaps 6) possible solutions.

For birders with lots of experience with the candidate species, the gamble can perhaps be reduced to a choice of less than 4 species. Certain combinations of features shown by the mystery bird may statistically occur more commonly in one species than another. For example, the mystery gull shows very white clean underparts without any dark streaking or patching. If the assumption is made that the mystery bird was photographed in the winter, then this may point to a Yellow-legged or Caspian Gull, rather than an American or European Herring Gull. The lightness of the grey (adult) back/wing feathers could have pointed to a Herring or Caspian Gull, rather than to a Yellow-legged Gull. We would welcome any further comments on this mystery bird from gull experts.

A 4cy Caspian Gull almost identical to the mystery bird with regard to the extent of immature markings is pictured here: http://gull-research.org/cachinnans/4cy/4cymarch01.html

PS: If no single winner will come out of round 25, then an additional ‘shootout’ round consisting of 4 mystery birds will be held between the leaders of the competition. If this additional round will still not result in a single winner, then the price winner will be drawn from the contestants with the highest score.

(JB)

Ranking after 24 rounds
name, score
Andrew Holden 20
Chris Batty 20
Nils van Duivendijk 20
Diederik Kok 19
Lazar Brinkhuizen 19
Davy Bosman 18
Dusan Brinkhuizen 18
Stuart Piner 18
Hein Prinsen 16
Raf Drijvers 16
Sietse Bernardus 16
Bas van den Boogaard 15
Bas van Gennip 15
Fedde Welbedacht 15
Jos Welbedacht 15
Julien Mazenauer 15
Willem Wind 15
Bram Vogels 13
Geir Mobakken 13