Thursday, 15 August 2013

Autumn migration is a GO melo GO

Blog courtesy of Gryllos blog
http://gryllosblog.wordpress.com/

Shaun and I met at 0600 at Durlston and as there were only two of us we only erected three nets. As on Saturday we were very busy from 0630 to 0730, then it tailed off quickly. Apart from the 76 Willow Warblers that we ringed, the most notable feature early on were the number of Garden Warblers (22 were in total, a new record for the site) and two Common Redstarts. By midday when I packed in we had ringed 117 birds
At 1030 I extracted a Melodious Warbler, this is a scarce but annual migrant in Dorset mainly in August, breeding as close as northern France. However nearly all Dorset records come from Portland and although I have seen several in the field I have never seen one in the hand. Unfortunately Shaun had to depart for work at 0930, so I was alone when it was trapped, but Hamish Murray was still in his office nearby and was able to get to see the bird.
Melodious Warblers belong to the genus Hippolais, members of which have typically wide based bills, square ended tails and short undertail coverts. Melodious is best told from its closest relative, Icterine Warbler, by the short primary projection, i.e the degree to which the primaries extend beyond the exposed tertials. Compared to the Willow Warbler that was trapped at the same time, it had a similar wing length of 66mm but was a larger, stockier bird with a much heavier bill.
This was certainly the highlight of my ringing this year, I just wish there had been another ringer present to enjoy it.

The plain face caused by the weak supercillium and pale lores, along with the stout, broad-based bill indicates a Hippolais warbler. The visible primary projection is only about half the length of the exposed tertials (equal in Icterine), with 7 primary tips showing. The tail projection beyond the tip of the primaries is at least twice the length of the exposed primaries (equal or less in Icterine) and the 1st primary extends well beyond the primary coverts (equal in length in Icterine).




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