During an internship for my Master studies at Wageningen University, the Netherlands, I got the chance to be part of an ongoing research project on White-fronted geese (Anser albifrons) at the Netherlands Institute of Ecology (NIOO-KNAW). We found that on their migration from the Netherlands towards their breeding grounds in northern Russia, birds followed a so called “green wave”, ie they tracked the very onset of grass growth during spring, but they arrived slightly before this peak at the breeding grounds so the peak would match with the date of hatching. Below is a figure showing the peaks of acceleration of vegetation greenness (“GDD jerk”) with indicated with arrows the arrival of individuals at these sites; the full paper can be found here.