Why is a stork called "Chasidah"?
Rashi: Because it performs acts of kindness with its friends.
Moshav Zekenim, citing R. Eliezer of Garmaiza: It gives Ma'aser 1 from its children. This is why the angels (Chayos) are called byits name - "Kenaf Renanim
Seifer ha'Itur (Shechitah 45b): Some call it 'Gita', since it casts them off (like Get). Pane'ach Raza: That explains why in Devarim, it is placed just four Pesukim before "Aser Ta'aser" (Pasuk 14:18).
Why is the heron called "Anafah"?
Chulin, 63a: Because it becomes angry with its friends.
What is a "Duchifas"?
Rashi: it is a wild hen, whose comb is doubled ('Hodo Kafus'), which Onkelos translates as 'Nagar Tura' because it is capable of boring holes in rocks. 1
As the Gemara relates in Gitin, 68b. Others, citing Rashi, translate it as a hoopoe.
Why is "ha'Anafah" written without a 'Vav' in front of it?
Moshav Zekenim: Because when a stork (which is written before it) is Mezanah with its friends, it immediately Tovels in water lest its 'husband' smell [the semen]. If it does not do so, if the male smells it, he will act like an Anafah, which is irritable and Mezanah, and it flies and breaks [the female's] neck with a feather in its wings.
QUESTIONS ON RASHI
Rashi writes that Chasidah does Chesed with its friends. If so, why is it among the Tamei birds?
Mishneh Halachos (6:124, citing the Ba'al Shem Tov), Daf Al ha'Daf (Chulin 63a citing the Beis Yisrael): Midas ha'Chesed entails doing Chesed with everybody and not only with one's friends.