Yan and Ying are an organic whole, which can be seen from the text. Jiang Kui's Walking on the Sand, "Yan Yan is light, Ying Ying is fine".
Hehe, just kidding. ...
Also, parrots (Xue Tao's Poems of Ten Departures)
There are many eagles, such as "grass withered and eagle eye disease, light snow."
Magpie, there are many songs in Dunhuang, but they are rare in later generations. It doesn't mean anything to report good news but not bad news.
The bluebird is the most common, although it is a fictional bird ... the messenger of the western queen mother, and later poems are often used as a symbol to convey love letters.