1cy american herring gull, Portugal

Please start a 'new post' for each other individual bird, to keep discussions separated.
Joined:Tue Feb 07, 2012 6:28 am
1cy american herring gull, Portugal

Post by Stefan » Thu Dec 26, 2019 12:15 pm

This american herring gull was found and photographed by Tiago Carvalho in the area of Leiria, Portugal on the 23rd of December 2019, but was also present on the 24rth. Most of the scapular feathers are juvenile, but there are some 1st generation feathers in the upper-left scapulars (the smallest scapular feathers). Such pale based bill would be unusual for european herring gull. However, few specimens of herring gulls that have glaucous genes may have similar bill like this one that require further study. The very smooth underparts are also different from the herring gull, and also to those smith look-alikes that may have velvety underparts. Other supporting features include 1) at least half of the anterior greater coverts have a darker band dorsally and 2) the tertials have a narrow white lining. Comparison of these features is needed to the Icelandic smith look-alikes. The outermost (distal) secondaries are bit paler than the inner ones. The inner primary window is perhaps more paler/conspicuous compared to many american herring gulls. Both these features may suggest more a european herring gull or a european herring gull with glaucous influence, but it is impossible to be sure. The head is quite greyish, but american herring gulls at this age have often paler head (but clearly there is a lot of variation). Nevertheless, considering the timing of the observation, then feathers on the head and breast should be of 1st generation. The tail feathers appear quite blackish, and it seems that the outer border of the outermost tail feather is black (while difficult to see) while the distal part of the feather is not. The barring of the upper tail coverts/rump and under tail coverts appear to be quite dense.
24-12-2019 c.jpg
24-12-2019 c.jpg (268.36KiB)Viewed 16185 times
24-12-2019 b.jpg
24-12-2019 b.jpg (268.95KiB)Viewed 16185 times
24-12-2019 a.jpg
24-12-2019 a.jpg (324.05KiB)Viewed 16185 times
23-12-2019 f.jpg
23-12-2019 f.jpg (274.53KiB)Viewed 16185 times
23-12-2019 e.jpg
23-12-2019 e.jpg (162.29KiB)Viewed 16185 times
23-12-2019 d.jpg
23-12-2019 d.jpg (235.38KiB)Viewed 16185 times
23-12-2019 c.jpg
23-12-2019 c.jpg (227.47KiB)Viewed 16185 times
23-12-2019 b.jpg
23-12-2019 b.jpg (260.33KiB)Viewed 16185 times
23-12-2019 a.jpg
23-12-2019 a.jpg (434.74KiB)Viewed 16185 times
Last edited by Stefan on Sat Dec 28, 2019 9:55 am, edited 1 time in total.

Post Reply