Jilguero translates to "goldfinch". It's a charming and somewhat uncommon word in song lyrics, making it stand out.
In the song, the goldfinch is used to symbolize the beginning of a relationship, as the singer mentions "en mi jardín un jilguero hicimos los primeros sus cielos" (in my garden, a goldfinch and I made our first heavens). This imagery evokes a sense of innocence and new beginnings, adding a poetic touch to the narrative of love and loss.
Los Cadetes De Linares bring us "Mi Unico Camino," a classic that really digs into the pain of a past love. The singer feels a deep wound, like a "vena clavada como puñalada" [a vein stuck like a stab wound] in his mind, and he laments how people might have laughed at him in a past life. He regrets how he was, calling it his "pecado" [sin], and he's been through so much sorrow, pain, and disillusionment from this love over the years.
He sings about how even a beautiful honeysuckle garden, where a goldfinch once sang its first notes, withered away, just like a love that was once like a mulberry tree also left him without a thought. It's a powerful image of how something once full of life can just dry up. He knows that if his former love ever wanted to return, forgetting the old resentment, she would find him with a glass of wine, which is the "único camino que me dio tu amor" [only path your love gave me]. It's a sad but honest look at how love can leave you with just memories and a drink to ease the pain.