Late breeding phalaropes in Ammarnäs

Normally, the Red-necked Phalaropes in Gelmetje start egg laying between 10-15 June, with some nest appearing a little later. This year, it took a long time before we found the first nest: an incomplete clutch on 21 June. Many pairs were still hanging around in pairs, apparently still in the process of finding a suitable nest location or still laying eggs. This give us the opportunity to capture several pairs, thus with females that yet have to start laying. These females were all surprisingly heavy: mostly between 40 and 45g. Until now, we only recorded such weights at the end of their stay, around 10 July.

We have managed to recapture two phalaropes with geolocators: both females! Surprisingly, one of these carried a logger that Tim and I gave her back in 2014. Amazing! The battery was empty, so we will have to return the logger to the manufacturer to get the data. Can’t wait to see her tracks! I am all the more curious as we have only a small number of tracks of females. Because phalaropes have reversed sex roles (except laying eggs, females do not contribute to incubation or chick care), females leave earlier than males, but also arrive earlier. With the growing number of tracks of females, we can investigate how females accomplish this early arrival (we already discussed this briefly in our JAB paper). Do they winter closer by? Do they migrate faster, or do they depart from the winter sites earlier than males?

Another bird with a geolocator, a remarkably pale male, and the partner of the female with the 2014 geolocator, remains to be recaptured. We will try again tomorrow!

IMG_2548_frapo
A satisfied Morrison looking at a male Red-necked Phalarope we captured last week.

Dunlins

Although we resighted three Dunlins with geolocators early in the season, we have failed to capture any of them. The valley where they were breeding last year is now virtually devoid of Dunlins (and Golden Plover). The last sighting of one of the geolocator-birds was in a flock of failed/non-breeders. Possibly, its nest was predated shortly after laying, when there was still a lot of snow. In Gelmetje, we did not see a single Dunlin this entire season, while the numbers in Björkfjället also appear low.

Sadly, Christian, Peter and Jesper, who have been of great help during the past two weeks, have left Ammarnäs. Only about a week to go for Morrison and me.

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2 thoughts on “Late breeding phalaropes in Ammarnäs

  1. Paula June 26, 2017 / 10:56 am

    No Dunlins? crazy! Is there a high predation this year? Very good luck with the phalaropes!

  2. robvanbemmelen June 26, 2017 / 11:26 am

    The artificial nest experiment indeed suggests there has been high predation pressure in Bjorkfjallet. Around the time of the experiment, 21+ Long-tailed Skuas, a Hooded Crow and some Raven were present in the area. Also some covered nests were predated, indicating predation by foxes (or other mammals). However, from the Dunlin nests we found, not a single has been predated… The absence of Dunlins in Gelmetje is really puzzling. No idea what could be the cause of this.

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