Mishneh Torah — Positive Mitzvot מצוות עשה, Chapter 148
The full Hebrew text of Mishneh Torah, Positive Mitzvot, Chapter 148, with English translation by Maimonides (Rambam).
לשלח הקן, שנאמר: "שלח תשלח את האם ואת הבנים תיקח לך" (דברים כב,ז).
To send away [the mother bird] from the nest [when taking the young], as [Deuteronomy 22:7] states: "You shall surely send away the mother."