The lower bird is smaller and dumpier with smaller, rounded head, greyer central crown stripe, two very broad white wing bars and, yes, lacks yellow on the undertail coverts.

• 下面那只鸟体型较小和粗短，并有较小而浑圆的头，较灰色的头央线，两条很宽的白色翼带，以及不带黄色的尾下覆羽。（冠纹柳莺特徵）