Friday 17 May 2013

17th May 2013 Arlington

Common Sandpiper 1
Swift c.5
Swallow c.75
House Martin c.75
Pied Wagtail c.15
White Wagtail 1 male



 
 
 
Male White Wagtail at Arlington
Being a late date for a migrant White Wagtail in the County this individual was worthy of close scrutiny but appeared convincing enough with an extensive white forehead, jet-black crown and nape sharply demarcated from its smooth grey mantle and all-black throat extending into an isolated black bib by virtue of its whitish-grey breast-sides. While it has broad white tips to its greater coverts the white edges are rather narrow. Its flanks washed with grey but retaining a rather 'clean' appearance.
 
Male White Wagtail at Arlington
When they come into contact yarellii and alba regularly interbreed but the resultant offspring are believed to show the blackish-grey rump of yarellii. Unfortunately typically hidden by folded wings and being such active birds I never find the rump colour easy to assess. So how do you read the above when 'shuffling' - black nape, grey mantle, grey back, darker grey rump and blackish uppertail coverts? Alstrom & Mild (2003) describe the rump for alba as 'only slightly darker grey than rest of upperparts'.
 
Male White Wagtail at Arlington
In this image its rump now appears far more convincingly only slightly darker grey than rest of upperparts.