Is this a question?
Rashi: Yes, it is said in astonishment. Therefore, there is Chataf Patach 1 under the Hei.
Radak says that it is a simple Patach, like our texts, and even so it is a question. (PF)
What is the comparison to a colored Ayit?
Rashi #1: Is Yisrael a vulture dirty with blood, that other birds gather against it?
Rashi #2: It is a colored bird. All other birds hate it, and gather against it to eat it.
Radak citing his father: A vulture colored with blood of corpses is around My inheritance that I chose. After the vulture is satiated, all wild animals come to eat - "Lechu Isfu..."
Malbim: Is My inheritance like a domesticated Ayit, which has two attributes?! (a) It is colored - its feathers are beautiful. (b) "Saviv Aleha" - it is used to being with people. All enjoy it, and it does not damage. No! My inheritance is like a lion, which people do not enjoy it, and it damages!
Why does it say "ha'Ayit Saviv Aleha"?
Rashi: Are all the fast troops around it birds of Shamayim 1 ?!
Why does it say "Lechu Isfu..."?
Radak: He tells the birds, after you are satiated, gather all the animals. The custom is, birds come first to a Neveilah, for they see it while flying - "uva'Asher Chalalim Sham Hu" (Iyov 39:30). The animals see the vultures colored with blood of corpses, and they leave their places. They are a metaphor for the nations that came with Nebuchadnetzar to destroy Yerushalayim. It is as if they made a sign and raised a flag; this is described as if the Ayit calls to the animals. This was a Nevu'ah.
Malbim: All animals should gather to fight this killer lion (all nations should gather to fight Yisrael).
What is the meaning of "Hesayu Le'achlah"?
Rashi: They came [to eat it]. Radak - Hei and Aleph are interchangeable. This is like Esayu - "Esayu Ekchah Yayin", "Shuvu Esayu" (Yeshayah 56:12, 21:12).
Malbim: Do not think that [the lion] is strong. Come to eat it - it is weak like a Seh, to be eaten.