May in Yellowstone marks one of the most dynamic periods of the year, bison calving season. Across Lamar and Hayden Valley, newborn calves, often called “red dogs,” begin to appear alongside protective mothers and tightly structured herds. These early days of life unfold quickly, with calves standing within minutes and staying close as they navigate a landscape still transitioning from winter to spring. For photographers, this is a rare opportunity to capture powerful moments of connection, vulnerability, and resilience. In this post, we explore bison behavior during calving season, where to find them across Yellowstone, and how to photograph these iconic animals while respecting their space during one of the most sensitive times of year.