Climate cycles and insect pests drive migration timing of reindeer's North American cousin

A new study led by a University of Maryland biologist discovered two unexpected drivers for migration timing that dispute long-held assumptions and provide insight into potential future effects of climate change on caribou. First, the start of migration is synchronized across North America and tied to large-scale, ocean-driven climate cycles. Second, warm, windless summers that favored insect pests lead to poorer maternal health and delayed arrivals at the calving grounds the following spring.