I’ve been back on Islay for a month now – and it’s flown by!
The most exciting thing about this autumn has been the chance to catch up with
our GPS tagged white-fronts from last year, hopefully combined with downloading
their valuable data gathered over their summer away.
Is it bad to have favourites? Tag 21
The initial joy at finding an old friend alive, well and
back on Islay with the tag still attached quickly changes to an extremely
nervous wait once the downloading kit is unpacked and pressed into action. Is
the tag still working? Will it send me the data? Will it painfully cut out halfway
through a download? When the numbers start whirring through on the computer
screen and the magic words "all data imported J" flash up (yes, it really does give you a J!)
there might have been a bit of a fist pump and a little jig; anyone who’s ever
seen me dance will know that’s not a pretty sight - hopefully no one was
watching..
Migration data! Spring-Autumn 2014
Different birds = different colours. Tag 21 is red, 22 is dark blue
The good news is that 6 birds willingly parted with their
data, giving us a remarkable insight into their migration routes, Icelandic
staging areas and remote West Greenland breeding areas – this location data
from the tags really is the next best thing to actually being there.
West Greenland happenings
It’s revealed some trials and tribulations associated with
migration – and strategies the birds use to overcome them. The return leg from
Iceland to Islay this year seems to have been particularly arduous – almost entirely
due to the weather. Tag “BLO 19” (before anyone says anything I know she needs
a proper name..!) left her journey really late, only leaving Iceland on the 10th
of November. She got her timings horribly wrong though, as she quickly met a
series of Gale Force South Easterlies once she was out over
the North Atlantic. Rather than pressing on into such a strong headwind and
wasting precious energy, she ditched and sat on the sea for at least 6-8 hours.
She did this twice more over the next 2 days before she made it to South Uist
on the evening of the 13th. Here she over-nighted before heading on
down to Islay in the morning. To put this 4-day marathon in perspective, Tag
BLO 27 completed the same journey (just less than 1500km), three weeks earlier,
in 16 hours. Clearly, though, this strategy worked for BLO 19 – maybe if she’d
ploughed into the headwind for 3 days she wouldn’t have made it at all –
definitely better late than never!
BLO 19 back to Islay. Circles indicate lengthy stopovers at sea
Wind map of the 12/11/2014 - middle of BLO 19's Iceland - Islay leg
Other birds tried a different tactic: just go with the flow!
Two of these windsurfers were tags BLO 21 and 22. They were both blown off
course on amazingly different paths back to Islay, 21 was up way north of the
Faroes at one stage (look at first picture - northernmost red line), whilst 22 was well to the North
West of the Irish coast (south-westernmost blue line). Other Greenland
white-fronts clearly experienced similarly tricky conditions; a bird from Loch
Ken in Dumfries and Galloway was seen in Norway, for instance.
In terms of ditching at sea these 3 Tundra bean geese in the
North sea have life sussed though: not just taking a rest from flying, but
catching a lift at the same time!
No comments:
Post a Comment