Geolocators!

Here’s a little update from Ammarnäs. Skua-wise, it’s been going very well, despite that ploughing through the thick layer of soft snow is tough. Virtually all skua nests contain two reasonably-sized eggs and the birds appear well-motivated to incubate. This probably attributed to the success rate of (re)captures. In only a few days, we (well, mainly Piet and Michiel) have done a tremendous job in recapturing no less than four birds with geolocators. Three of them were geolocators mounted last year, but one special individual, with colour ring code AA, was a true prize-bird! Its geolocator contained almost four years of data! The tracks of the tracked birds showed they all wintered off South Africa, in the Benguela Current. That’s pretty far; they migrate around 40.000 km each year

Individual AA starred in a recently published paper in the Dutch Birding magazine (please drop me a line if you would like to have a PDF). It is a short cautionary note about ageing Long-tailed Skuas, showing that AA retained barred underwing coverts for at least five years (and this year for its sixth year). In the literature, such barred feathers are related to immaturity, but this individual shows that this needs not to be the case. Obviously, this article is really for true bird nerds.

AA back in 2011, when he first got his geolocator.
AA back in 2011, when he first got his geolocator.

The situation looks much less favourable for the phalaropes: all lakes in Gelmetje are still frozen. Just the day before yesterday a tiny bit of phalarope-habitat thawed. They are all in the delta waiting to get up. We regularly see birds taking off, apparently for inspection flights. Hopefully, they will be able to start breeding soon, because if they don’t, we won’t be able to retrap the individuals with geolocators and we won’t be able to deploy any new loggers!

Meanwhile, I got home and Hans & Daniel just arrived at Slettnes. Hence, more news is expected soon!

A fat little lemming; Piet in the background.
A fat little lemming; Piet in the background.
KR or KJ breeding his/her two eggs, surrounded by fresh snow.
KR or KJ breeding his/her two eggs, surrounded by fresh snow.
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2 thoughts on “Geolocators!

  1. Åke Lindström June 10, 2015 / 4:43 pm

    Hi there guys, congratulations on a great job! I am really curious to here more about the AA bird – how it behaved near Ammrnäs in those two non-breeding years 2012 and 2013.

    Remember there is no bad weather, just bad clothing! (-: /Åke

  2. robvanbemmelen June 10, 2015 / 4:54 pm

    Hi Åke! There is not much info in the light data for June 2012 and 2013, but I expect (but didn’t check yet) much interesting stuff in the wet/dry data (for those readers who don’t know: the loggers also record whether or not they are submerged in seawater). The data from the loggers retrieved last year appear to show what we already expected in the field: in both non-breeding years the birds went back and forth between the mountains and the sea. Jannie Fries Linnebjerg is now looking at this data and comparing it with data from Svalbard and Greenland, so if you walk into her office (if she is there?) I’m sure she can show you some nice graphs! (Otherwise drop me a line!)

    You’re absolutely right! Once we borrowed snow shoes we were able to conquer the snow! 😉

    All the best, Rob

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