Breezy and overcast at Rysjön in the morning with a slow ringing session just saved by a few more Siskins (easily the highest ringing total for this species in over 40 years) and most interestingly, a re-trap adult female Savi’s Warbler – originally ringed on 25th August accompanying that very late, young fledgling and coming to the end of a very mixed, interesting summer-partial moult.
A good array of other bits were seen through the morning including 2 Pink-footed Geese which came onto the lake with some Taiga Beans (a Swedish tick!), a big female Goshawk over the other side playing with a range of other raptors and Ravens such as the 6 Marsh Harriers and a Rough-legged Buzzard, 3 Goosanders, a Little Grebe, 3 White-tailed Eagles sat together at first light and a lingering Tree Pipit.
Savi’s Warbler – this bird was originally ringed on 25th August as a breeding female and was accompanying an extremely young fledgling which had almost certainly left the nest that morning from close by to give a fairly accurate timeline for it moult (not that I know how soon after their chicks fledging that they begin their post-breeding moult).
The moult is very interesting and as far as I know typical for Savi’s Warbler although most probably leave and start on migration before starting primary moult – perhaps the lateness of this birds breeding exacerbated the need for it to moult before migrating; primary moult started at P7 and worked outwards leaving three old inner primaries with the secondary moult following a similar pattern, starting at S3 and working outwards. There was one retained, old primary covert corresponding to the new moulted primary and the tail looked like it was replaced.
No comments:
Post a Comment