Chulin, 115a: It teahes us that Shilu'ach ha'Ken is a La'av ha'Nitak la'Asesi (a La'av that can be rectified by performing an Asei), and is therefire not subject to Malkos (until the perpetrator nullifies the Asei). ¹

Chulin, 139b: It may be eaten, because, knowing that one is liable to not take the eggs, the Torah would not command us to send away the mother, thereby causing people to sin ? albeit inadvertently. ¹

Chulin 138b: It implies that Kodshim birds - which one is obligated not to send away, but to bring to the treasurer of Hekdesh - are not subject to the Mitzvah of Shilu'ach ha'Ken. ¹

Chulin, 141a: "Shal'each" implies even four or five times ? even a hundred times. ¹ "Teshalach" teaches us that the obligation to send the mother bird away applies even if one wants the babies for a Mitzvah - to be Metaher a Metzora. ²

Rambam, Hilchos Shechitah, 13:3: It precludes where Shimon came and snatched the mother bird from Reuven's hands and sent it away or where it flew away by itself - if Reuven then takes the babies, he is Chayav Malkos. ³

Chulin, 141b: As soon as the mother leaves his hands ¹ he is permitted to take the eggs.

Chulin, 140a: It implies 'take for yourself, and not for your dog'' ? the Mitzvah does not apply if the mother is sitting either on the eggs of a Tamei species ¹ of bird or on fledglings that are T'reifah ² that cannot be eaten ³ .

Rosh: The mother is Yerushalayim, which is called the mother of Yisrael. The children are Yisrael. They were sent away ?"u've'Fish'achem Shulchah Imchem" (Yirmiyah 50:1). "Kilah Hashem es Chamaso? va'Yatzeis Eish be'Tziyon" (Eichah 4:11). When Yisrael sinned, Hashem wanted to destroy His world ? "Im Lo Brisi [? Shamayim va'Aretz Lo Samti" (Yirmiyah 33:25). He said, I will destroy My house and finish My anger on the wood? Lema'an Yitav lach."

Chulin, 141a: One is not permitted to do so, since the Torah specifically writes "Shale'ach Teshalach es ha'Eim ve'es ha'Banim Tikach lach", and not vice-versa. ¹

Rashi #1: We learn from it that if this is the reward that the Torah gives for an easy Mitzvah that costs nothing ¹ , how much more so for Mitzvos that are difficult (and costly) to keep.

Rashi #2 (in the original manuscript): From here and from a similar statement "Lema'an Ya'arichun Yamecha" ? in Va'eschanan, 5:16, in connection with Kibud va'Eim ? the Chachamim learned that one should reckon one's losses when performing a Mitzvah against ones gains' - As the Mishnah states in Avos 2:1 'Be careful to perform a lesser Mitzvah just like a severe one, since the Torah mentions Arichus Yamim both by Shilu'ach ha'Kein and by Kibud Av va'Eim.

Seforno: We learn from it that even for the small measure of Chesed involved in not destroying the species, ² by sending away the mother bird, one reaps the benefits in this world, ³ whilst the principle is reserved for the world to come.

Targum Yonasan: "Lema'an Yitav lach" implies 'in this world', and "Veha'arachta Yamim", 'in the world to come'. ⁴

Hadar Zekenim: If you send the mother, it will be good for you, since it will give birth to more litters, and you will find them, and you will cause the mother to live a long life.