Why should Black-tailed Godwits still winter in West-Africa if Southern Iberia is just as good?:Expedition report Guinea Bissau, December 2015, University of Groningen & Global Flyway Network

From 7-19 December we visited Guinea Bissau on a Black-tailed Godwit ring-readingexpedition. We had planned our visit in December because we had hoped to get betterviews of the (legs of the) birds when the rice had been harvested. Last year we werehere in November and it was sometimes problematic to see them well. Later inDecember godwits are supposed to leave towards their staging areas in Iberia beforemoving on to their breeding locations in NW-Europe.Our itinerary mainly focussed on the huge rice fields along the Mansoa River. Asexpected, the fields near Unche and Pache Iala turned out to be the primary locationfor godwits (max. 1250 godwits) but we were surprised to see that nearly all othersites we visited were almost without any birds. We could not find a clear clue for thatbecause fields were very comparable with harvest in full swing, dry fields close to thevillages and wet fields towards the mangroves and plenty of rice to forage on, eitheron the plants, on the fields or on the dams. The birds we saw were all in excellentcondition and seemed ready for migration and had an average fat score (abdominalprofile) of 3,7 on a 1-5 scale (n=30).As visiting random ricefields that looked good based on aerial pictures did not turnout to be a very fruitful strategy, we switched to visiting also the more remote siteswhere birds with satellite transmitters had very recently been seen like Ilha de Pecixeand the area north of the Rio Cacheu. We found some small flocks of around 200individuals at each of these sites but we never encountered large flocks like in Uncheor near Mansoa in 2014. This meant that getting resightings was troublesome andafter 10 days we finished our mission with 85 sightings of 48 individuals. In theweeks before our departure the satellite tagged birds already showed quite somemovements in a northerly direction and we think we were simply too late to see bignumbers. As far as we can see, the reason for this departure can’t be adverseconditions in Guinea Bissau where conditions were good and food was plenty.