Solution to Puzzle 3

We are presented with a series of clues, each with a sequence of blanks that presumably fit the answers. However, none of the clued words have the right letter counts to fit in the blanks. We notice that every answer has a substring which is a bird name, and these birds fit the blanks:

1. Device for heating food: miCROWave
2. City near Lake Michigan famous for breweries: milwAUKee
3. Two 19th century explorers who crossed the Continental Divide: lewis and cLARK
4. Relating to dental pulp: enDODOntology
5. The US _ or the USS _ : consTITution
6. Mac DeMarco album and DJ Khaled catchphrase: anotHER ONe
7. Explosive part of a missile, or a brand of candy: aiRHEA
8. Vehicle for transporting babies or precocious pets: stROLLER
9. Exeter rival: anDOVEr
10. Object of the third Indiana Jones movie: holy gRAI L
11. Inventor of the cyclotron: ernest laWRENce
12. Thigh bone: fEMUr
13. Study of the "End Times": esCHATology
14. The B-2 and F-117A are notable for this: sTEALth
15. The "most trusted man in America": walter cronKITE
16. NFL championship game: superbOWL
17. Reagan said "missed me" when one of these popped: balLOON
18. Main ingredient in the national drink of Senegal: hIBIScus

The highlighted letters spell the puzzle solutoon, CARDINAL DIRECTIONS