Ruiseñores translates to "nightingales". It's a beautiful and somewhat rare word in everyday Spanish, evoking a sense of classic romance and natural beauty.
In the song, it's used to paint a vivid, nostalgic picture of
Monsieur Periné's "Viejos Amores" is a beautiful, nostalgic look back at past loves, the kind that sweep you off your feet with grand gestures. The singer remembers a time when lovers would "conquistaban con poemas" [conquered with poems], and she secretly dreamed of "robar por primera vez un beso y más que eso" [stealing a first kiss and more than that]. It's all about those classic, romantic connections.
She holds onto these memories, describing them as "arrugas que dejó el dolor sobre mi cuerpo" [wrinkles that pain left on my body], showing that these experiences, even the painful ones, have shaped her. She waits for these "viejos amores" [old loves] with a longing similar to how "el viento espera el abandono del otoño" [the wind awaits autumn's surrender], ready to escape with the yellow leaves. It's a sweet, almost melancholic reflection on the loves that stay with us, becoming a part of who we are.