- While they nest extensively across the northern two-thirds of Arizona and the broader American West, they pass through the southern desert valleys in beautiful flocks during their standard spring and fall migrations ... Notably, southern Arizona serves as a critical evolutionary molting hotspot
- Large numbers of these birds pause their late-summer migration in southern Arizona to take advantage of monsoon-fed bounty, remaining for one to two months to fully replace their feathers before moving further south into wintering grounds in western Mexico