We were pretty keen to get out ringing this week but a steady wind of 15-20 mph made it impossible for days on end. The usual check on late Wednesday afternoon suggested those pesky isobars might just pull apart for Thursday morning, so I arranged to meet Andy up at Okenclough for a ringing session.
"Maybe" weather
Back home there was a hint of (unforecasted) drizzle at the off. As I drove up to Oakenclough, 600ft above sea level, the drizzle intensified with a wind from the North West at about 8-10mph. At first “light” there was 100% low cloud with light but spasmodic drizzle.
But we stuck to the task in hand, the drizzle eased as the light improved slowly and we packed in about 11 am. During the whole time there was very little visible migration but in the circumstances we managed a reasonable catch, mainly Redwings.
The birds caught tell the story of the morning: 17 Redwing, 4 Coal Tit, 2 Goldfinch, 2 Goldcrest, 2 Blue Tit, 1 Great Tit.
In the heavy cloud conditions with very low visibility the visible migration of thrushes was virtually zero. We had maximum counts of 180 Redwing and 40 Fieldfare, mostly arriving from unseen directions as they dropped through the cloud cover. Otherwise, the count of small birds was negligible.
The field sheet shows how at least three of this morning’s Redwings were of the Icelandic sub-species, Turdus iliacus coburni, rather than the nominate European race Turdus iliacus.
Spot the Iceland Jobs
Birds of the Icelandic subspecies are marginally larger and darker than nominate birds from Europe but only around 10-15% of Icelandic birds have longer wing lengths, so relatively few are separable on size.
But this morning it was noticeable how at least 50% of Redwing wing lengths were in the 120’s rather than the mid to late teens of recent ringing sessions.
The three biggest came in at wing lengths of 129 mm, 127 mm and 124 mm with corresponding respective weights of 76.5 gms, 68.5 gms and 68.9 gms. Compare these three monsters with three of the smallest – 113 mm with 56.7 gms, 117 mm with 58.9 gms, and 117 mm with 61 gms.
Icelandic Redwing
European Redwing
We’ll be trying again soon so let’s hope for a few windless days and more light for more photos.
Linking today to Eileen's Blogspot and Anni's Birding.
