Will birds and fish cease?
Radak #1: This is an exaggeration (Malbim #1 - metaphor), like Yirmeyahu said "me'Of ha'Shamayim v'Ad Behemah Nadedu Halachu" (9:9) and Hoshe'a said "b'Chayas ha'Sadeh uv'Of ha'Shamayim v'Gam Degei ha'Yam Ye'asefu" (4:3).
Radak #2, Malbim #2: Yes. [Malbim - domestic] birds are found only in settled places, where there are seeded crops, fruits and budding trees. When a settled place become desolate, they go to another settled place. Also fish multiply primarily in seas close to settled places. Malbim - they distance from desolate shores, for there are no people who cast food to the sea.
What do we learn from "ha'Machshelos Es ha'Resha'im"?
Rashi: This is idolatry. Malbim #2 - the verse discusses matters that make Resha'im stumble.
Radak: Stumbling blocks will find Resha'im to stumble in them. I.e. afflictions will come to greet them, to stumble in them and die.
Radak citing Targum Yonasan: Stumbling of Resha'im is great.
Malbim #1: They will be eradicated with the Resha'im.
Why does it say "v'Hichrati Es ha'Adam"?
Radak: The verse began "Asef Adam." It specified Resha'im to compare them to birds; the Resha'im will not escape ha'Machshelos - the sword, hunger and plague. Others who are not total Resha'im, and Tzadikim, will be exiled. The land will be desolate, without people or animals.
Malbim: This is the purpose [why all these matters will be eradicated]. Nebuchadnetzar destroyed most nations.