I spotted a redstart in the woods, its orange-red tail feathers standing out brightly.

redstart 是由 red（红色）和 start（古英语中"尾巴"的意思）组成的复合词，指"红尾鸲"这种鸟类。这种鸟的特征是尾部羽毛呈鲜艳的橙红色。