Ammarnäs: returning phalaropes!

Finally some news from Ammarnäs. Up until today, we had quite a ‘slow’ season. Lemming abundance has plummeted in late-winter, and thus virtually all Long-tailed Skuas are skipping this breeding season (except some weirdos far south at Kraipe and Aigert). We observed some small or medium-sized flocks of skuas that will probably make it back to sea in the coming two weeks.

Hence, our main target has been to (re)capture Red-necked Phalaropes in phalarope-city, Gelmetje. However, this didn’t went smoothly in the last week; we did find some nests, but couldn’t find any birds carrying geolocators. Nor did we find the usual ‘female-flock’ at lake Gelmetje. Deploying all available loggers therefore seemed difficult. This all changed today. While some males have been incubating for about 10 days, we now encountered a decent number of females and found a new nest of a male with logger, containing very freshly laid eggs! We didn’t manage to catch this male (yet!), but we did recapture a female with a logger it got last year by Tim, Michiel and Piet. Great!

The big surprise came only when we returned to the research station: it is one of the two females of which we already had a track! Thereby, the two years of data from this individual sheds some first light on one of the questions brought up by the paper in Journal of Avian Biology on phalarope migration. In this paper, we show that Red-necked Phalaropes usually use several areas within and adjacent to the Arabian Sea, instead of staying at a single site during the entire winter. For example, an individual may arrive in the Gulf of Oman, stay there for some time, then fly south to the spend some time along the southern Omani coast, and subsequently travel to the Gulf of Aden. These movements are presumably in response to monsoon-driven changes in where and when food is available, and the question is to what extent these movements are similar between years. Are they direct responses to local circumstances, changing from year to year, or routes learned during early life, and repeated in subsequent years? This female stayed at three distinct sites during the 2014-15 winter, but spent the entire winter in the Gulf of Aden during 2015-16, thereby showing that individuals can change itineraries between winters.

The female that returned to Gelmetje for a second year with a geolocator full of data.

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