It’s been along time since anything appeared on the ‘over the treeline’ blog, but with the 2015 field season approaching it is a good moment to look back on the past winter and to look forward to the plans for the coming months.
I have been mainly analysing data obtained from geolocators of Long-tailed Skuas and Red-necked Phalaropes, which should result in two papers. Meanwhile, Paula and Juan have written a very nice paper in the Journal of Avain Biology regarding the migration and winter movements of Golden Plovers. Maybe they’ll blog about this soon…
Next week, I’ll leave for Ammarnäs with Piet Admiraal and Michiel Elderenbosch. Both bird ringers, they will have a major role in the fieldwork, as I’ll be leaving very early this year (7 June) to get back to my pregnant girlfriend in the Netherlands…! The famous Johannes will join this year (bringing his family up to Ammarnäs. Johannes, Piet and Michiel will later be joined by Tim, who will bring his phalarope catching skills back for his second season in Ammarnäs. Guido and Fons will also visit for their second year, and will round up by (colour)ringing skua chicks and catching some more phalaropes.
The main aim for this season is to retrap skuas and phalaropes carrying geolocators and deploy new loggers. There is a number of questions that we hope to answer using the data obtained from these loggers. In a large collaborative study combining geolocator data from Greenland, Iceland, Scotland, Sweden, Norway, Finland and Russia, we’ll aim to describe (contrasting) migration strategies and routes across the North Atlantic. The migration routes and wintering areas of Red-necked Phalaropes breeding in the Western Palearctic have long been debated, in particular those breeding on Iceland and other North Atlantic islands. These populations may winter in the Pacific Ocean, while the Scandinavian birds should all winter in the Arabian Sea.
It seems like the pattern in lemming densities of the early ’80s is repeating. Following a huge peak (2011), two low years (2012-2013) and a mediocre year (2014), there are some rumours about good lemming numbers this spring. This is expected to result in a good number of breeding skuas. Hopefully they will be willing to hand in their geolocators, but with new techniques and a very eager field crew, I trust this will be a succesful year!
Meanwhile, a team (Jasper Koster, Thomas Lameris and Stefan Sand) has already left to Tobseda, Russia, to retrap Arctic Skuas and Red-necked Phalaropes. In the first week of June the first field crew will leave for Slettnes, focussing on the same species set. Hans Schekkerman and Daniel van Denderen will leave first, followed after two weeks by Ingrid and Daan Liefhebber. Let’s hope for a good number of retraps!