Wing moult in Barnacle Geese shifts following climate change (RiS ID 11429)

In a 30-year time series, barnacle geese advanced their breeding season in two clear warm seasons (2006, 2016) following the general advancement in spring snow melt of 0.4 days/year. Thirty years ago, 17 days after hatch of the juveniles, the adult geese start their primary moult and are flightless for 28 days. Both parents moult highly synchronized with each other and their young and were able to fly almost at the same day. With the advancement of the start of breeding also the timing of moult has advanced. A preliminary analysis suggest a longer time interval between hatch and moult, a lower speed of feather growth and more asynchrony between the two sexes with males being slower than females. Data on the timing of moult are collected by visual observations (when are the primaries disappearing and when are they returning in individually marked geese) and by measuring the length of the longest primary during catches, when groups of moulting geese are driven in a catch pen. We want to combine timing of breeding based on the hatch date of the goslings and start of moult based on visual observations and/or backdating primary length during catch. By collecting intensive observations in 2020 but also by analyzing the data series from 1990 onwards. The preliminary analysis presented above needs statistical scrutiny to be tested. The duration of the flightless period is highly relevant for survival as this is usually a dangerous period with a lot of predation by arctic foxes.