American Herring Gull (smithsonianus)
(last update: October 30, 2015)
American Herring Gull (smithsonianus) adult.
P7 (figure 8, table 6-7)
Basically, the characters to be looked for in P7 are the same as those in P8 but the pale tongue is (nearly) always very long in all forms, and is therefore not helpful. The presence of a ’bayonet' is significant, either on P7 or P8, or on both); see table 5. The amount of white on the tongue-tip should also be noted, although the difference is less obvious than in P8. In some birds, the black colour of the outer web not only projects in a ’bayonet’ or pointed wedge along the outer edge but also slightly along the shaft, thus creating a rather forked or ’V’-shaped pattern (eg, plate 228).
The shape of the black pattern on the outer web is another important character. On the outer web of P7, many NF smithsonianus have a rather peculiar shape, which we would like to call the ’bayonet pattern' (see figure 7a and 8a). Basically, the pattern consists of a straight or slightly oblique upper border, which then projects towards the primary coverts in a thin, very pointed black wedge (almost ’needle-shaped’) along the outer edge. The shape recalls a French ’bayonet', hence the name. It is important to note the difference with the pattern in figure 7c and 8c: these also show a pointed black wedge towards the primary coverts but it is broader at the base, starting from the shaft and lacking a distinct step. The combination of the three characters mentioned above (’bayonet’, tongue-tip, length of tongue) is significant, as can be seen in figure 7a and the percentages below it.