Moerdijk Field Research 2005-2006
(last update: 14 August 2010)
|Larus argenatus argenteus, Moerdijk, the Netherlands.
In what way do Dutch Herring Gull resemble American Herring Gull (L. smithsonianus)? Starting point is the article in Dutch Birding by Bruce Mactavish & Peter Adriaens.
Peter and Bruce mention these features for adult birds:
.1: P10 should have a broad rectangular tongue, combined with a complete sub-terminal band; as is shown in the picture above.
.2: P5 should show a complete black "W".
.3: And a few extra’s, which add to the ID: bayonets (black continues along the feather edge, white 'moons' (tongue tips are white between grey centre and black sub-terminal band), and also a black "W" on P6.
First, for the Moerdijk birds, we have checked if the smithsonianus-pattern for P10 & P5 did occur in this population:
ad 1: A complete sub-terminal band on P10 can be found in 27% of the Dutch Herring Gulls (85 birds out of 319). But only 9 birds (3%) combine this complete sub-terminal band with a rectangular corner in the medial band.
ad 2: The P5 "W" was recorded in 26 birds.
The combination for P10 & P5 was more or less pretty okay in HG mVZ & HG oHE.
Below: Herring Gull mVZ:
Below: Herring Gull oHE:
Continue at: SECOND SET OF FEATURES for smithsonianus.