Mishneh Torah — Negative Mitzvot מצוות לא תעשה, Chapter 306
The full Hebrew text of Mishneh Torah, Negative Mitzvot, Chapter 306, with English translation by Maimonides (Rambam).
שלא ליקח אם על הבנים, שנאמר "לא תיקח האם, על הבנים" (דברים כב,ו).
Not to take a mother bird together with the young, as [Deuteronomy 22:6] states: "Do not take the mother bird together with the young."