Scientists from the Abisko Research Station above the Arctic Circle in northern Sweden catch, weigh, and measure migratory birds on the shores of Lake Tornetrask to monitor the impact of climate change and shifting weather patterns on their movements. Head of the research station Keith Larson and a research assistant set nets in the forests on the shores of the lake to catch the birds before taking them to measure their weight, wingspan, note their age and sex, and placing a ring on their legs to track them once they have been rereleased into the wild. IMAGES AND SOUNDBITES ARRANGED IN SEQUENCES