Higher body weight is a frequent indicator of dominance. The blue jay is large, heavy, loud, typically aggressive, and capable of mimicking hawk calls—all factors that can displace the downy.

You’d think its pecking might help, but the downy is displaced by the jay and its higher body weight—a frequent indicator of dominance. The blue jay is also loud and typically aggressive.

The chickadee avoids confrontation and cannot outcompete the downy and most other species because of its small size and light weight.

The chickadee doesn’t fare well at feeders. It avoids confrontation and cannot outcompete the downy and most other species because of its small size and light weight.

The cardinal and the downy generally avoid each other. But when they fight, the heavier cardinal is defeated thanks to the woodpecker’s tree-hammering skills.

This is a close one. The cardinal and the downy generally avoid each other. But the heavier cardinal is defeated thanks to the woodpecker’s tree-hammering skills.

These two woodpeckers have a similar diet and habitat, which fuels frequent conflicts. The red-bellied is bigger than the downy and often displaces it.

These two woodpeckers often go beak-to-beak. Both have a similar diet and habitat, which fuels frequent conflicts, but the red-bellied is bigger than the downy.

They have similar weights and don’t interact much, but the woodpecker tends to win. Why? We’re not sure. The house sparrow is invasive to North America, and scientists think its status in the social hierarchy may still be shifting.

This is a tricky one. The downy and house sparrow have similar weights, but the woodpecker tends to win. The house sparrow is invasive to North America, and scientists think its status in the social hierarchy may still be shifting.