The Exploding Chest Display
Male sage-grouse gather at traditional 'leks' before dawn, inflating yellow chest sacs and making bizarre popping sounds to compete for females.
Each spring, male greater sage-grouse gather at traditional display grounds called leks to perform one of North America's most spectacular courtship rituals.
The display involves: 1. Males puff up their chests to reveal two yellow air sacs 2. They fan their spiky tail feathers into a starburst 3. They strut forward while inflating and deflating the chest sacs 4. The sacs produce a distinctive "swooshing pop" sound 5. The whole display is synchronized and repeated for hours
Leks can have 20-100+ males, all displaying simultaneously. The visual effect is extraordinary — dozens of birds inflating bright yellow balloons against the gray sagebrush landscape.
Females watch from the edges, evaluating displays. Competition is fierce because mating is extremely skewed: - About 10% of males do 75% of all mating - Many males display for years without ever mating - Females choose based on display quality and lek position
Central lek positions are most desirable, and males fight fiercely to hold them. A male's position indicates his dominance status.
Leks are used for generations — the same sites have been documented for over 100 years. This cultural transmission means losing a lek can be devastating for local populations.
Sage-grouse depend entirely on sagebrush habitat, which is threatened by development. Their dramatic courtship displays have made them a symbol of western conservation efforts.