Complex sentence: Before developing the full display finery with coloured ruff and tufts, the males replace part of their winter plumage with striped feathers; females also develop a mix of winter and striped feathers before reaching their summer appearance.
Split into simpler sentences: Before developing the full display finery with coloured ruff and tufts, the males replace part of their winter plumage with striped feathers. Females also develop a mix of winter and striped feathers before reaching their summer appearance.