Why does Juliet want to believe the birdsong she can hear is a nightingale and not a lark?

The
morning afterconsummate their marriage,prepares to leave 's room before the sun rises and the
day begins. Romeo must flee to Mantua because he has been exiled from Verona for killing . If
Romeo remains in Juliet's room any longer, he risks being captured by the authorities.

At the beginning of act...