The Shrike Nest is Foehn's main anti-air defense structure, which uses a Shrike drone armed with the ubiquitous Golden Rocket launcher to engage enemy aircraft.
Dig a deep, reinforced hole in the ground, hide a small drone in it and you've got Foehn's basic anti-aircraft defense: the Shrike Nest. The Shrike hides within these holes, waiting for enemy aircraft to approach and once they get in the Nest's range, it launches and begins its pursuit.
This small drone will fire a bunch of the infamous "Golden Rockets" at the enemy, before returning to the Nest to reload. The big advantage in the use of the Shrike Nest over the more ordinary anti-air defenses is that once a Shrike locks on an aircraft, it will pursue it even if said unit leaves the Nest's range. The Shrike will keep firing until it runs out of ammo.
As Foehn's basic anti-aircraft defense, the Shrike Nest comes with two advantages. Firstly, it can be buffed by a SODAR Array, as with all units that use the Golden Rocket, and secondly, the Shrike will continue its pursuit until the target is dead or it runs out of ammo, beyond its intended range.
However, relying only on one or two defenses is not enough to stop major aerial threats, such as multiple Kirovs. It is best to deploy this structure in large numbers and deploy SODAR Arrays nearby. Furthermore, Shrikes can be shot down by AA and are not as effective against countering fast jets or projectiles. Supplement it with more Shrike Nests, Teratorns and Knightframes to properly deal with dangerous aerial threats.