The lyric "A bird in your teeth" from Phoebe Bridgers' song "I Know The End" can be interpreted in several ways, as it is often the case with song lyrics that convey complex emotions and imagery. Generally, the phrase evokes a surreal and unsettling image, suggesting feelings of anxiety, chaos, or the unexpected burdens we carry in life.
In the context of the song, which deals with themes of mortality, despair, and the inevitability of endings, this line may represent a juxtaposition of the beauty and harshness of existence. The "bird" might symbolize something beautiful or fleeting, like a dream or aspiration, while being "in your teeth" could imply that it's caught in a difficult situation or causing discomfort.
Ultimately, interpretation is subjective, and listeners may relate to the line in personal ways based on their own experiences and emotions. The imagery in "I Know The End" as a whole helps to convey the complexity of feeling both hope and despair simultaneously.