Birds are pretty sensitive when it comes to temperature. Some species struggle to keep warm during cold winters. Other birds have expanded their range northward as global climate has warmed. Scientists can use this close relationship between temperatures and bird behavior to predict bird diversity. This information is useful for guiding conservation efforts, such as how to manage a landscape. The map shows relative temperatures during the winter across the United States. It shows where temperatures are warmer (red) or cooler (blue) than the median temperature detected. 2013–18.