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? Chasidah" (Iyov 39:13).
Pane'ach Raza: Targum Onkelos of "Chasidah" 'Chorisa', since it is common for Chasidim to turn white (after blushing) when people mock them for their Chasidus, and even so they do not refrain.
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.