frostbird

例句：

1. 1. The frostbirds were singing their mournful songs in the early morning.
   霜鸟在清晨唱着它们的悲伤之歌。
2. 2. The frostbird's delicate plumage makes it a popular subject for birdwatchers.
   霜鸟那精致的羽毛使它成为观鸟者热衷的研究对象。
3. 3.The frostbird's song is a melodic reminder of the cold winter days.
   霜鸟的歌声是寒冷冬日的美妙提醒。